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Savings Tips

Find cost-effective ways to use energy more efficiently

energy-saving-tips

Everyone likes to save money. We've compiled a list of simple tips to help you save on energy and keep your bill as low as possible, while also helping protect the environment.


Inspect and maintain boilers

The costs of properly maintaining boilers are fully recovered in fuel savings. To ensure peak efficiency, remove scale, replace leaky tubes and flanges, remove damaged insulation and control linkages, and recalibrate controls.

Install an economizer to increase the efficiency of a boiler

To increase the efficiency of a boiler by 2 to 3 percent, install an economizer. This device preheats the feedwater (returned condensate). In the case of a 250 horsepower boiler, an initial investment of $6,000 provides an annual savings of more than $3,000.

Keep boiler insulation in good condition

For peak efficiency, repair or replace damaged or missing boiler insulation.

Minimize excess air in boiler operations using 02 trimmers

To increase boiler efficiency, minimize excess air using O2 trimmers which adjust the amount of air supplied to the burner. Most boilers operate with more air than is required for the combustion process, wasting energy.

On any large boiler, use a blow-down heat exchanger

On any large boiler, use a blow-down heat exchanger to preheat the make-up water going to the deaerator. This measure conserves energy by reducing the energy required to preheat the make-up water and by partially cooling the blow-down water prior to discharge to the sanitary server.


The time to add roof insulation is when you are building or replacing the roof. Whether the project is a 19th century historic property with a lead-coated copper roof or a flat-roofed industrial building from the 1930s, roof replacement is an opportunity to add insulation, including a vapor barrier. This is one of the most cost-effective energy conservation measures available. The cost to increase insulation is a small portion of the overall roofing project and can result in a rapid payback.

To conserve energy, allow elevators to timer out and shut down slowly. They should idle long enough so that the power consumption is equal to or just less than power consumed in motor generator starting.

To improve the thermal-insulating characteristics of aluminum frame windows, specify that the window must include a thermal break-an insulating section placed between the inner and outer aluminum sections of the frames. With a thermal break, aluminum frame thermal conductivity characteristics approach that of wood.

Artificial lighting and air conditioning consume the largest amount of electrical energy in a typical commercial building. The two are tied together in that the more artificial lighting used, the greater the heat load imposed on the air conditioning system from lamps and ballasts. Carefully increasing the amount of natural light will decrease the need for artificial light, reducing energy in both lighting and air conditioning systems. However, West facing glass can bring in a significant amount of heat which can be costly to cool in the warmer months. Consider planting trees that lose their leaves in multi-story buildings to shade this glass.

Newer elevators are more energy efficient than older ones which use motor generators that run constantly. Despite this benefit, energy savings alone do not justify the cost of installing new elevators. New direct drive elevators may still be a good investment because they save on maintenance costs and are environmentally kind.

When designing new facilities or renovations, select strategies to control heat flow and light energy to minimize energy costs. Light energy can be controlled using overhangs to shade windows, shading glass surfaces, and using glazing material for exposed window surfaces. Other methods for controlling heat flow include selecting the correct materials for the walls and roof and using natural ventilation and landscaping. Our Energy Experts can help you select those strategies which provide enough savings to justify their expense.

Just enlarging window openings will not correct daylighting problems. Daylighting needs to be distributed relatively evenly, and that becomes more difficult as a building rises several stories. Near the ground level, some daylight bounces off the landscaping and streetscaping to balance the directional light from the sky. But in high-rise buildings, that balance must be accomplished artificially by using reflectors and diffusers often built into the glass.

Seventy-five percent of a building's total air loss is from small leaks. Seal electrical outlets and gaps between moldings, as well as plumbing and wiring penetrations. Attic checkpoints include hatches, plumbing vents, chimneys and other roof or wall penetrations. Many areas can be sealed with a caulk gun and tubes of silicone or urethane caulking. For larger areas, foam sealants may work best. Outlet plugs and foam pads that are installed behind outlet and switch covers are wise investments.

Incorporating low-E glazing will improve the energy efficiency of your facility year-round. During the cooling season, long-wave infrared radiation from outside the facility is blocked before it can pass through the glass, thus reducing the cooling load. During the heating season, long-wave infrared radiation from objects within the facility is reflected back into the conditioned space, thus lowering the heat loss through the glass.

Uninsulated brick walls are very common, especially in buildings constructed prior to 1960. These walls can be insulated using three methods-furring the interior surface, insulating the cavity or insulating the exterior. Furring the interior surfaces is relatively simple, inexpensive and provides a finished wall surface. Generally, the interior is framed with studs or runners, insulation is placed between the runners, and the surface of the wall is finished.

In addition to their aesthetic values, interior window treatments can reduce energy consumption. Insulating vertical or horizontal blinds and/or draperies can reduce heat loss and solar gain through window openings.

Keep an eye out for solar heat gain. Solar heat gain, particularly in buildings with large areas of south-facing glass, can cause serious problems in maintaining comfort levels. Window tints or reflective coatings are available that will reflect up to 90 percent of the solar heat gain striking the window. The windows can provide energy savings in all but the most northern climates, where solar heat gain can make a significant contribution to reduce the winter heat load in the building. As a rule of thumb, if the walls of a building are more than 25 percent glass, the building can benefit from solar control glass. The further south and the higher the percentage of glass, the higher the percentage of solar energy that should be blocked.

Proper landscaping not only increases the attractiveness of a facility, but also decreases energy consumption in smaller, low-rise buildings. Trees, planted near their mature size, provide shade for low, east- or west-facing windows. Both trees and shrubs control glare from neighboring buildings, shade parking lots, reduce the temperature of the pavement, and lower the temperature around a building. Plants control and funnel breezes into ventilated portions of buildings where the direction and speed of the prevailing winds are dependable.

In addition to increasing the attractiveness of a building site, landscaping can be put to use to decrease energy consumption in smaller, low-rise buildings. Deciduous trees can be planted to provide shade for low, east- or west-facing windows, although they have to be planted near their mature size in order to achieve a significant effect. Trees and shrubs can control glare from adjacent surfaces and materials such as neighboring buildings and reflecting glass surfaces. They can also shade parking lot surfaces, reducing the temperature of the paving materials and lowering ambient air temperatures around buildings. Finally, plant materials can be used to control and funnel breezes into ventilated portions of buildings where the direction and speed of the prevailing winds are dependable.

New facilities or renovations can be designed to control heat flow and light energy in a way to minimize energy costs. The key is to examine the various strategies for envelope energy conservation and to select those strategies which provide enough savings to justify their expense. These strategies include: incorporating overhangs to shade windows; shading glass surfaces from radiant heat while introducing natural daylight into a building, or selecting the appropriate glazing material for exposed window surfaces; selecting the correct materials for opaque surfaces (walls and roof); and using natural ventilation and landscape materials where appropriate.

To prevent 75 percent of a building's total air loss, seal subtle leaks. Seal electrical outlets and gaps between moldings, as well as plumbing and wiring penetrations. In the attic, pay particular attention to hatches, plumbing vents, chimneys, and other roof or wall penetrations. In smaller areas, use a caulk gun and several tubes of silicones or urethane caulking. In larger areas, use foam sealants. Outlet plugs and foam pads installed behind outlet and switch covers are wise investments, particularly in campus-like building complexes in colder climates.

Select replacement windows with a 0.46 U-value or better, with optical properties that are appropriate for building use. (U-0.46 is a low-E window in a thermally improved metal frame.)

To improve the energy efficiency of your facility year-round, use low-E glazing in your windows. During hot weather, this glazing blocks long-wave infrared radiation before it can pass through the glass, thus reducing the need for air conditioning. During cold weather, long-wave infrared radiation from objects within the facility is reflected into the conditioned space, lowering heat loss through the windows.

Internal walls influence window design and placement. Highly reflective-but not glossy-light-colored walls will spread daylight back from sidewalls. Jewel-toned walls will absorb more light and may require more supplemental lighting sources.

If you can't stand the heat, leave the heat out of the kitchen! A building had many offices with large windows facing south. Even with the shades drawn, the air conditioning could not keep up. The owners considered increasing chiller capacity by 50 percent. Instead, an energy engineer suggested window films. Now the offices are comfortable without the addition of chiller capacity. The electric bills have gone down. And the occupants can leave their shades open to enjoy the view. Window films not only reduce air conditioning loads but also help reduce heating energy use. In optimum situations, energy savings frequently pay back the cost of film installation in a year or less. In a surprisingly large number of cases, building owners have been able to pay back the cost of window film installation directly from energy savings.


Consult the experts

Take advantage of expert advice by asking your local utility for technical energy audits, payback calculations, cost comparisons, rate analyses, fuel cost projections, and estimates of future rate increases. It is staffed with representatives specializing in commercial energy applications who are eager to assist you.

Perform energy audits

Perform regular energy audits to establish the basic costs and uses of energy forms including electricity, gas, and steam, and to identify waste or inefficiency. By identifying on-peak and off-peak periods, you can take advantage of a utility's rate structure.


Provide all air handling units with an economizer with enthalpy control. Applications include all areas and buildings that can use outside air for "free cooling" during a significant portion of the year. This reduces the energy required to operate a chilled water plant.

To avoid losing efficiency, calibrate pneumatic thermostats every three to six months. The exact frequency depends on the condition of the air supply and how often occupants tamper with thermostats.

Maintaining cleaner heating and cooling coils by using and regularly changing filters can lead to greater efficiencies. Effective filter replacement schedules will reflect changes of use in the building. (See Electronic Air Cleaners.)

After reducing system head loss, you will probably find you have more water running through the system than the chiller and pump can handle within specified limits. The next step is to consider having the manufacturer trim the pump impeller (or change the pump) to deliver the specified GPM (about 2.4 GPM per ton) at the new, lower total head loss. If you measure flow and power at the pump motor, you could see a performance of about .026- .03 kw/ton.

Changing from a terminal reheat system, which provides good thermal comfort but is known for its poor energy efficiency, to a variable air volume system can have significant savings. For example, the conversion at a 10,000-square-foot dental clinic in Texas reduced chiller energy use by at least 50 percent and heating fuel by nearly 70 percent.

Although individual components of the HVAC system, such as the chiller, may be quite efficient, the overall system may contain inefficiencies that need to be remedied.

When specifying piping insulation, look at both the maximum temperature it will be exposed to and the minimum temperature. For example, the piping serving the fan coils in a building was insulated with a high R-value material, based on the maximum temperature it would be exposed to. The contractor, however, failed to take into consideration that the piping would also carry chilled water. Consequently, the insulating material had no vapor barrier. During the air conditioning season, moisture condensed within the insulation, destroying not only its insulating properties but also the pipe it was supposed to protect.

For greater HVAC system efficiency, clean and maintain its mechanical parts. Check for dirty coils and filters that restrict air flow, loose fan belts, outside air dampers that do not close correctly, and improperly functioning control valves.

Cooling towers are one of the most overlooked opportunities for saving energy in cooling plants. Cooling tower technology has improved over the last 10 years. The average tower today operates at about .12 kw/ton, while new, efficient, plastic-filled, counterflow towers can perform at .011 kw/ton (10 times better). These efficient towers use less fan horsepower per unit of cooling but, more importantly, they deliver cooler water to the chiller(s). For centrifugal chillers, each degree F the condenser water temperature is depressed, the chiller efficiency will increase about 1 percent.

For some areas of the country, evaporative rooftop cooling is reducing summer cooling loads by as much as 25 percent. Prior to installation of such a system, a 124,000-square-foot software development facility in Dallas calculated that it needed to add 41 tons of additional air conditioning to adequately cool the building. What building owners discovered was the water-spray rooftop cooling cut the cooling load, allowing the company to recover the costs of its installation in one year.

Consider a thermal storage system when designing your chiller plant. With a thermal storage system, the idea is to run chiller equipment off-peak and store cooled water or ice, then draw on this cooling during the peak times of the day. These systems take one of three forms: chilled water, ice or a salt-water hybrid of both-called a eutectic system. Specifying which system is based on the availability of space for storage media, cooling load profile, rate schedule and current equipment.

Pump and fan capacities can be reduced and energy saved by using variable speed drives to control their speed. However, don't forget to consider taking low-cost measures to reduce capacity, especially where the pump or fan is running at constant speed most of the time. For instance, if a fan is driven by V-belts, its capacity can be changed by altering the size of the drive pulleys. Similarly, a pump's capacity can be changed by trimming its impeller. These are low-cost alternatives to expensive electric drive modifications. Reductions in both peak and off-peak energy costs can be obtained by using variable speed drives on pumps, fans and compressors that operate at varying loads. The use of these drives will have little impact on demand because they will require the same kilowatts at peak-demand periods as fixed speed drives. They pay off better if the systems they are applied to operate at part load for relatively long hours.

Consider installing water-loop heat pumps. Applications for these systems include schools, medical centers, hotels, offices and even small airports. Why? There are opportunities for energy recovery from core areas and from simultaneous heating/cooling situations. The energy recovered can be redistributed to space conditioning and domestic water heating. Costs are typically low for installing, operating and maintaining these systems. And they are adaptable to future energy sources, such as solar heating. What's more, individual unit control means greater flexibility and comfort.

Control cooling tower fans by sensing ambient wet bulb (wb) temperature. Adjust the set point for an approach of about 2°F (controller will measure outside wb and adjust set point to 2°F warmer). A word of caution: Don't try this tip with old inefficient towers. The increase in fan kw will eat up chiller efficiency gains.

Consider controlling all the cooling tower fans with one variable frequency drive and modulate the fan speed together.

Realize significant savings by changing from a terminal reheat system to a variable air volume system. Such a conversion at a 10,000-square-foot dental clinic in Texas reduced chiller electricity by at least 50 percent and heating fuel by nearly 70 percent.

Save energy by using low-cost measures to reduce pump and fan capacities. For example, alter the size of the drive pulleys of fans driven by V-belts. To reduce a pump's capacity, trim its impeller. These changes are much less expensive than electric drive modifications.

Reuse waste heat. Many opportunities exist to reuse thermal energy within a building. For instance, rejected waste heat from air conditioning or refrigeration equipment can often be used to serve building needs. To capture waste heat, hot gas desuperheaters, double-bundle condensers and auxiliary condensers can be used on just about every type of air conditioning and refrigeration equipment. Whether the recovery and reuse of waste equipment is practical, however, depends on the availability of and simultaneous need for that energy. The potential energy savings and cost benefits depend on how many hours-per-year of excess energy are available and also on whether that heat can be used for purposes that would otherwise require purchased energy.

At present, many air conditioning systems are being replaced due to the phaseout of ozone-depleting refrigerants. This is an excellent opportunity to incorporate design features that reduce the cooling load on the system. Updating the system results in lower equipment and energy costs.

During renovation or expansion, consider increasing the size of distribution piping or, in the case of retrofit, adding parallel pipes to double the cross sectional area of the flow path. Amory's theorem states: "The energy required to move water (or air) through a pipe varies with the inverse fifth power of pipe diameter."

Before making any attempts at modifying the boiler or its controls, the boiler should be inspected and all controls recalibrated to ensure that the system is operating at its design efficiency. Scale build-up, leaky tubes, leaking flanges, damaged insulation and worn control linkages all contribute to losses in efficiency. Good maintenance practices always are a worthwhile investment, and the annual costs are recovered fully in fuel savings.

Use a boiler blowdown heat exchanger to preheat make-up water going to the deaerator. This can be used on any larger steam boiler that has continuous blowdown. This measure reduces the energy required to preheat make-up water and partially cools blowdown water prior to discharge to the sanitary server.

The installation of an economizer, a device that preheats the feedwater (returned condensate), typically will increase the efficiency of a boiler by 2 to 3 percent. In the case of a 250 hp boiler, this can result in an annual fuel savings of more than $3,000, for an initial cost of approximately $6,000.

Install instrumentation to monitor realtime, cooling plant efficiency in kw/ton.

Insulate exposed hot-water, steam and chilled-water distribution piping and valves where feasible.

To reduce costs, investigate using the economizer cycle to cool a building at night.

Think system efficiency when making decisions about conservation strategies. For instance, you may have the most efficient chiller available, but if parasitic loads from chilled water and cooling tower pumps are high, then the system efficiencies could be quite low.

To improve cooling tower efficiency, lower the cooling tower fan horsepower by adding surface area and free area within tower fill. These additions result in a 5 to 10 times lower load on the cooling tower fans. The motors can therefore be resized. The tower performance goal should be .012 kw/ton or better.

To conserve energy, make inexpensive repairs and improvements to the HVAC mechanical system as required. For heating efficiency, repair or replace burners and add radiator reflectors. Install flue dampers or balance the ventilation system to reduce the exhaust rate. Relocate thermostats, install fans to keep hot air off the ceiling, and install thermostats in hot water tanks.

The effectiveness of an energy management system largely depends on the physical condition of the equipment it is intended to control. No system can achieve the best efficiency if a mechanical system is plagued with dirty coils or filters that restrict air flow, loose fan belts, outside air dampers that do not close correctly, or improperly functioning control valves.

Minimize "excess air" in boiler operations. In order to ensure complete combustion, most boilers are designed to operate with excess air (more air than is theoretically required for the combustion process). However, this excess air reduces the boiler's efficiency. If excess air can be minimized, efficiency gains of 1 to 2 percent can be realized. Excess air controllers (sometimes called "O2 trimmers") are available. They control excess air by sampling combustion products and adjusting the amount of air supplied to the burner accordingly. For a 250 hp boiler running 2,000 hours per year, the installation of an O2 trim system would result in an increase in efficiency of 1 to 2 percent, which is equivalent to an energy cost savings of about $1,700. Initial cost of a unit for a package boiler of this size is approximately $9,000. If the boiler ran for more than 2,000 hours per year, the savings would be correspondingly higher.

While leakage in the condensate return system is inevitable, such leaks should be kept to a minimum. It takes approximately .150 Btu/lb. to heat make-up water from 50°F to 200°F. One leak at one drop per second represents almost 3 million Btu wasted annually, or $16.50 in wasted fuel, assuming the fuel is gas costing 44 cents a therm.

To avoid costly waste, keep leaks in the condensate return system to a minimum. Leaking one drop per second wastes $16.50 annually, assuming the use of gas at 44 cents per therm.

To improve chiller performance, monitor outside air temperature and humidity to control chilled water supply temperature. Even in hot, humid climates, you can increase the chilled water supply temperature and still maintain building comfort year round.

Consider installing instrumentation to monitor real-time, cooling plant efficiency in kw/ton. The saying goes, what gets measured, gets done. If efficiency is your goal, then you need an indicator of how well you are doing.

In multiple tower/chiller installations, run all the water over all the fill when possible.

Simultaneous heating and cooling is a senseless waste of energy and is easily preventable. You can recognize this problem by investigating unusually high utility bills and by performing energy audits. The management of a department store, when confronted with an abnormally high electric bill, solved its simultaneous heating and cooling problem by widening the thermostat deadband. During a routine energy audit of a manufacturing plant, a faulty air conditioning valve was discovered. Replacing the valve saved the plant $1,000 per month in energy costs!

The coefficient of performance (energy used per ton of cooling) can be improved by raising the chilled water supply temperature and lowering the condenser water temperature. Maintain condenser water as cool as possible (with clean and efficient cooling towers), but not less than 20 degrees above chilled water supply temperature.

Raise the cold air temperature set point at the thermostat. Most air conditioning systems are designed to maintain temperatures at 72°F to 75°F dry bulb (db) and 50 percent RH (relative humidity). Higher temperatures and slightly higher humidity levels can be maintained without noticeable discomfort to the room occupants. Increasing room conditions from 74°F db and 50 percent RH to 78°F db and 55 percent RH will save approximately 13 percent of the energy required for cooling.

To improve chiller performance, raise the temperature of the chilled water supply, and lower the temperature of the condenser water. Keep the condenser water as cool as possible, but not less than 20 degrees above the temperature of the chilled water supply.

Raising the cold air temperature set point on your thermostat can result in significant energy savings without causing noticeable discomfort to room occupants. Most air conditioning systems are designed to maintain a temperature of 72°F to 75°F and 50 percent relative humidity. By raising room conditions to 78°F and 55 percent relative humidity, you can save approximately 13 percent of the energy required for cooling.

Structures such as hospitals, universities, and industrial facilities use high- and medium-pressure steam containing valuable energy that can be recovered. Avoid venting this steam into the atmosphere where its heat is wasted. Instead, use the recovered heat to preheat domestic hot water or returned hot water from the building's heating system.

Whenever medium- or high-pressure steam boilers are used, there will be flash steam in the condensate system. This flash steam contains valuable energy that can be recovered. High- and medium-pressure steam is used in many types of structures, including hospitals, universities and industrial facilities. Good uses for the recovered heat are preheating domestic hot water or preheating returned hot water from the building's heating system. From 5 to 15 percent of returned condensate will flash to steam at approximately 5 psi. If this steam is vented to atmosphere, the heat is wasted. In addition, the vent will produce a visible plume of steam, which may be undesirable.

Of all the things you can do in a cooling plant to save energy, reducing pump power offers the greatest savings for the least cost. The trick to the following tip is to exploit the cube law of pumps (and fans). This law says that the energy required to move water varies directly with the cube of the total head loss across the system (pump). Head loss can be decreased by systematically reducing pressure losses in the distribution system. This can be accomplished by eliminating bypass valves and three-way valves; removing auto flow valves, pressure regulating valves and other flow restrictors; and opening balancing valves at the pump.

For peak efficiency, radiation loss from a boiler should be minimized by keeping insulation in good repair. It may not be worthwhile to add to existing insulation, but old, damaged or missing insulation should be repaired or replaced.

Monitor outside air temperature and humidity to control chilled water supply temperature (chilled water reset strategy). For centrifugal chillers, each degree F you raise chilled water supply (CHWS) temperature above 42°F increases chiller efficiency by 1 percent. Even in hot, humid climates, you can increase CHWS temperature and still maintain comfort in the building much of the year.

In plants with multiple cooling towers and chillers, run all the water over the tower fills when possible.

Often, critical items of equipment are provided with 100 percent redundancy. (One standby operates when the normal unit is out-of-service.) By providing three units each with a capacity equaling 50 percent of total load rather than two units able to serve 100 percent of total load, you save first cost and create the opportunity for additional energy savings. The units can be sequenced so that additional units can come on-line only when the running units are operating at full load. Applications include air compressors, vacuum pumps, heating water pumps, boilers and chilled water pumps. Benefits: One unit sized at 50 percent can handle the load 65 percent of the time, thereby saving energy associated with operating one larger unit at a less efficient part-load condition.

Shutting down unnecessary auxiliary HVAC equipment improves system efficiency without impacting performance. To save energy in central HVAC plants, turn off auxiliary equipment such as cooling tower fans and circulating pumps for chilled water and condenser water when not required.

Shut down unnecessary auxiliary equipment. Large central HVAC plants require auxiliary equipment like cooling tower fans and circulating pumps for chilled water and condenser water. This equipment should be shut down when not required. This does not result in lower chiller coefficient of performance but does improve the efficiency of the overall system.

Investigate using the economizer cycle to subcool a building at night, much like a whole house fan in your home. The economizer cycle should be enthalpy controlled to reduce operation when outdoor air is too humid.

A survey of mechanical systems can reveal a host of opportunities for conserving energy, often at a relatively small initial cost. Heating efficiency may be improved by: repairing or replacing burners; adding radiator reflectors to direct heat; installing flue dampers or balancing the ventilation system to reduce exhaust rates; relocating thermostats; installing destratification fans to keep hot air off the ceiling; or installing thermostats in hot water tanks.

Using a thermal storage system in the chiller plant conserves energy, particularly when there is a significant difference in energy demand between on-peak and off-peak hours. Three types of thermal storage systems are available: chilled water, ice, and hybrid. With a thermal storage system in place, you run the chiller equipment during off-peak hours and store cooled water or ice. You then draw on this cooling during the day.

To reduce the energy required to operate a chilled water plant, use an economizer in the air handling units of areas that use outside air for "free cooling."

Consider free cooling with cooling towers in commercial buildings and industrial plants where space conditioning or process cooling is done with mechanical refrigeration. When the cooling requirements are year-round, in cool months, they may be met with just cooling tower operation alone. How? By taking advantage of the large number of hours of low ambient wet bulb (wb) temperatures. The refrigerant compressor is turned off during this period, accounting for large energy savings. This is weather dependent, and proper analysis and design is required for both retrofit and new construction applications. Simple payback is possible in two to five years.

Use cooling towers to save energy in cooling plants by delivering cooler water to the chillers. Cooling tower technology has improved ten-fold over the last ten years.

Consider using electronic air cleaners in building air handling units in lieu of standard bag or cartridge filters. Electronic air cleaners have less air resistance, and the resistance remains constant. A standard filter's air resistance increases as the filter gets dirty. Air resistance increases fan static pressure, which in turn means motor energy use increases. Electronic air cleaners can be used in any type of commercial or industrial building. Energy savings will occur because of the decrease in static pressure resulting from the use of electronic air cleaners. The amount of the decrease is dependent on static pressure created by other system components.

Use energy estimating software as an analysis tool. Two restaurants were owned by the same person. The number of meals served per day was the same. The size of the buildings was the same. The amount of equipment was the same. But one used much more energy than the other. A detailed inventory was done and the results were fed into a building energy simulation software package. The results showed that the restaurant using more energy actually had five older, less efficient rooftop HVAC systems, compared to four newer ones at the other restaurant; had much more incandescent lighting; and had gas cooking equipment with greater standby losses and a higher ventilation rate. All of these contributed to the higher energy bills. The simulation effort made an apples-to-apples comparison possible.

Use energy estimating software to identify ways to increase energy efficiency and lower utility bills. For example, assume that two separate restaurants occupy the same sized buildings and serve the same number of meals daily. Oddly, the energy bills for one restaurant are significantly higher than for the other. After performing a detailed inventory of each site, the results are fed into a building energy simulation software package. The results show that the restaurant with the higher bills has an older HVAC system, uses more incandescent lighting, and has less efficient cooking equipment. The use of such software analysis makes an "apples-to-apples" comparison possible.

More may be better than less when it comes to saving energy. In two Ohio retirement and nursing home communities, the owner reduced gas usage by as much as 30 percent by using three smaller, high efficiency units instead of one large single, gas-fired boiler for each wing in the two complexes. Sequencing allows only those boilers required to meet the heating load to be fired, thereby reducing standby losses and increasing seasonal operating efficiency.

Steam turbines can be used to recover valuable energy from pressure reducing valves (PRVs). PRVs can be bypassed by back-pressure turbines, which exhaust steam at the same pressure as the PRV yet produce useful work. For example, they can be used to drive a generator, pump, chiller or compressor. A back pressure turbine operating at 250 psi supply and 15 psi exhaust, expanding 20,000 Btu of steam per hour, can drive a generator producing as much as 129 kw. If this operates for 6,000 hours per year, the electricity produced is worth more than $38,000 per year if you are paying 5 cents per kwh.

Using variable frequency drives to control the motors of variable air volume fans saves a significant amount of energy when the system is operating at low cooling loads. A study conducted by the Commonwealth Edison Company found that this modification results in an energy savings of 48 percent.

To reduce both peak and off-peak energy costs, use variable speed drives on pumps, fans, and compressors operating at varying loads. The use of these drives has little impact on demand because variable speed drives require the same kilowatts during peak-demand periods as fixed speed drives.

Many variable air volume fans operate at constant speed over the system's entire operating flow range. The fan flow is controlled by opening and closing dampers to provide cooled air to the conditioned spaces. A significant amount of energy is wasted when the system is operating at low cooling loads. A variable frequency drive (VFD) can be used to vary the speed of the motor, thus allowing the fan to match its output to the varying system load. A study conducted by Commonwealth Edison Company, in which inlet guide vanes equipping 200 hp supply and 50 hp return fans were replaced with a VFD, found that the VFD provided average energy savings of 48 percent. In this case, the result: annual energy savings of $15,734.

Watch out for simultaneous heating and cooling! At one department store, electric bills were unusually high. Investigation showed that half of the 10 rooftop systems were heating and half were cooling at the same time. This was fixed by widening the thermostat deadband to prevent simultaneous operation. In the office of a manufacturing plant, the refrigerant control valve was stuck open on a large direct expansion (DX) split air conditioning system. As a result, it was cooling well into the heating season. The mixed air controller caused the heating coil to reheat the air, so the occupants never knew there was a problem. This was discovered during an energy audit. Fixing the valve saved about $1,000 per month.

Use a water-side economizer system instead of the more common air-side economizer when the air supplied to the space must be kept within tight humidity limits. Using an air-side economizer would introduce low humidity air to the space that would then have to be humidified. A water-side economizer means that chilled water is cooled by the cooling tower without mechanical refrigeration when outdoor temperatures are low enough. Minimum outdoor air is introduced to the space by using this method. Applications include laboratories, hospitals, data processing centers and other areas where specific minimum humidity levels are required. Savings will be highest when electric humidification must be used and when the ambient conditions are very dry. Savings from this measure will vary based on local conditions, but the cost of humidification must be considered when making system selections.

When practical, recover and reuse waste heat from air conditioning and refrigeration equipment. Potential energy savings are based on how many hours-per-year of excess energy are available, and whether that energy can be used for purposes that would otherwise require purchase. Waste heat capturing equipment includes hot gas desuperheaters, double-bundle condensers, and auxiliary condensers.


There are three ways in which lighting energy use can be reduced by building owners: implement a greater degree of control over the use of lighting, use more efficient lighting equipment and apply better lighting system design strategies. Translated into a general guide, the goals statement for a comprehensive lighting energy conservation program should read: turn it off when it isn't needed; use the most efficient, suitable equipment; and provide light only where it is needed.

When retrofitting an existing lighting system, look at the task being performed in the space. In many cases, high overall light levels can be reduced when good task lighting is installed. A combination of good, sensible lighting design with the use of the latest technology lighting systems can result in substantial energy savings and an overall improvement in lighting quality.

Fixtures that have state-of-the-art lamps or ballasts (T8 lamps, electronic ballasts, etc.) may save plenty of energy but may also require a higher premium at relamping or reballasting time. Much of this cost is offset because of the longer life. This longer life not only cuts down on replacement component costs but also reduces the associated labor expense to replace them.

Even if you have already retrofitted a lighting system with energy-efficient core-coil ballasts and "watt miser" lamps, you can get further savings with a T8 conversion. The T8 system is, in most cases, the best retrofit method for existing fluorescent lamps. T8 lamps and ballasts are much more efficient than standard lamps and ballasts and their use creates an opportunity for delamping by astute use of reflectors, new lenses and "overdriven" ballasts. Often, existing four-lamp fixtures can be retrofitted with three or even two T8 lamps and ballasts and still maintain the same light output. Fixtures that have state-of-the-art lamps or ballasts (T8 lamps, electronic ballasts, etc.) may save plenty of energy but may also require a higher premium at relamping or reballasting time. Much of this cost is offset because of the longer life. This longer life not only cuts down on replacement component costs but also reduces the associated labor expense to replace them.

Full-range and "step" fluorescent dimming systems can significantly reduce the power delivered to fluorescent lights and can even be activated in response to available daylight for perimeter areas. While fluorescent control systems can be costly, the potential savings are great. A simple wallbox-mounted occupancy sensor (infrared or motion detector) can save a significant amount of money.

Incorporate motion detectors where they make sense. Suppose that you have fixtures with U-shaped fluorescent lamps normally rated at 18,000 hours of life (at 12 hours per start). If you use the fixtures every day of the week for 12 hours each day, the lamps should last approximately four years before they burn out. Let's say you determine that the offices are only used for two three-hour periods each day. You decide to install motion detectors in these spaces. Now, at three hours per start, the life of these lamps is reduced to 12,000 hours. Even so, because of the reduced usage, they will last about 5 1/2 years before they burn out. You have extended the time between relamping by 1 1/2 years (37.5 percent) and consequently lowered your maintenance costs. You have cut down your energy bill by 50 percent at the same time.

When considering lighting system retrofits, remember that the least expensive part of the system on a life-cycle basis is the fixture and lamp. The most expensive component is the energy that the system uses.

Employ special strategies to help distribute daylight evenly in multiple-story buildings. Simply enlarging window openings in such structures does not solve the problem. This is because near the ground level, some daylight bounces off the landscaping and streetscaping to balance the light from the sky. In high-rise buildings, you can achieve balance artificially by using reflectors and diffusers built into the glass.

When incorporating energy-efficient lighting technologies, it's important to remember that every facility is different. Without careful thought as to which are best suited for your particular application, you will not achieve the best rate of return on your energy conservation investment. In some applications, it will make sense to replace the entire incandescent fixture with a fluorescent one. In others, it is better to simply replace the incandescent lamp with a compact fluorescent lamp.

Replace your 10, or 20 watt incandescent lamps in exit signs with 5 watt compact fluorescents (CFLs). While the incremental energy savings may seem small, the continual operation of exit signs makes the retrofit very cost effective. Retrofitting a two lamp 15 watt incandescent sign with two, 5 watt CFLs will save approximately 175 watts, or about $15 per year. The cost of retrofit kits may be covered by utility rebates, resulting in a very quick payback. These savings are dwarfed in comparison to the maintenance savings from fewer lamp changes. A typical incandescent exit sign lamp needs to be changed every two months; a CFL needs to be replaced less than once a year. (And some fluorescent retrofit kits have two lamps which operate in tandem thereby reducing by half the number of trips up the ladder to change a lamp.) Assuming 20 minutes per lamp change, you can save about two hours of labor per year per exit sign by converting to fluorescent. In a building with 100 exit signs, this results in a maintenance savings of five weeks labor time per year. LFD and electroluminescent exit light fixtures can be an effective alternative to CFLs.

Full-range and "step" fluorescent dimming systems can significantly reduce the power delivered to fluorescent lights and can even be activated in response to available daylight for perimeter areas. While fluorescent control systems can be costly, the potential savings are great. A simple wallbox mounted occupancy sensor (infrared or motion detector) can save a significant amount of money.

Lighting control is perhaps the most important element of any lighting energy conservation program. Its benefits are concrete, measurable and, in most cases, quickly realized. Many lighting control projects have payback periods of less than one year. On/off controls are most suitable for applications where lighting is not needed for extended periods of time, but where manual switches might be left on. The choice between occupancy sensors and time-based controls should be based on the nature of the operation being performed in the affected space. For example, hallway lighting in office buildings is generally needed only during scheduled hours and therefore well-suited for time-based controls. If lighting is needed on a more random basis, such as private offices, occupancy sensors provide a better level of control and greater energy savings. Daylighting control systems examine the total amount of light available in a given space and switch off one or more banks of lights whenever enough sunlight is available. Daylighting control systems are particularly well suited for use in facilities with large areas of exterior glass.

When incorporating energy-efficient lighting technologies, it's important to remember that every facility is different. Without careful thought as to which are best suited for your particular application, you will not achieve the best rate of return on your energy conservation investment. In some applications, it will make sense to replace the entire incandescent fixture with a fluorescent one. In others, it is better to simply replace the incandescent lamp with a compact fluorescent lamp.

Suppose that you have fixtures with U-Shaped 'fluorescent lamps normally rated at 18,000 hours of life (at 12 hours per start). if you use the fixtures every day of the week for 12 hours each day, the lamps should last approximately four years before they burn out. Let's say you determine that the offices are only used for two three hour periods each day. You decide to install motion detectors in these spaces. Now, at three hours per start, the life of these lamps is reduced to 12,000 hours. Even so, because of the reduced usage, they will last about 5 ½ years before they burn out. You have extended the time between relamping by 1 1/2 years (37.5 percent) and consequently lowered your maintenance costs. You have cut down your energy bill by 50 percent at the same time.

Increasing the amount of natural light used in your facilities dramatically lowers your utility bills. The more artificial lighting used, the greater the heat load imposed on the air conditioning system. This is a critical point because artificial lighting and air conditioning consume the largest amount of electrical energy in a typical commercial building.

Lighting control is perhaps the most important element of any lighting energy conservation program Its benefits are concrete, measurable and, in most cases, quickly realized. Many lighting control projects have payback periods of less than one year. On/off controls are most suitable for applications where lighting is not needed for extended periods of time, but where manual switches might be left on. The choice between occupancy sensors and time based controls should be based on the nature of the operation being performed in the affected space. For example, hallway lighting in office buildings is generally needed only during scheduled hours and therefore well-suited for time-based controls. If lighting is needed on a more random basis, such as private offices, occupancy sensors provide a better level of control and greater energy savings. Daylighting control systems examine the total amount of light available in a given space and switch off one or more banks of lights whenever enough sunlight is available. Daylighting control systems are particularly well suited for use in facilities with large areas of exterior glass.

Even if you have already retrofitted a lighting system with energy efficient core coil ballasts and "watt miser" lamps, you can get further savings with a conversion to T8 lamps.

Replace your 10-, 15-, or 20-watt incandescent lamps in exit signs with 5- or 7-watt compact fluorescents (CFLs). While the incremental energy savings may seem small, the continual operation of exit signs makes the retrofit very cost effective. Retrofitting a two-lamp 15-watt incandescent sign with two, 5-watt CFLs will save approximately 175 watts, or about $15 per year. The cost of retrofit kits may be covered by utility rebates, resulting in a very quick payback. These savings are dwarfed in comparison to the maintenance savings from fewer lamp changes. A typical incandescent exit sign lamp needs to be changed every two months; a CFL needs to be replaced less than once a year. (And some fluorescent retrofit kits have two lamps which operate in tandem, thereby reducing by half the number of trips up the ladder to change a lamp.) Assuming 20 minutes per lamp change, you can save about two hours of labor per year per exit sign by converting to fluorescent. In a building with 100 exit signs, this results in a maintenance savings of five weeks labor time per year. LED and electroluminescent exit light fixtures can also be an effective alternative to CFLs.

It's a good idea to replace incandescent lamps with compact fluorescent's (CFLs). When doing so, the proper ratio is about 3 1/2% incandescent watts to 1 compact fluorescent watt. There may be an aesthetic problem with replacing incandescent lamps with CFLs in "can" fixtures because these fixtures are not designed for CFLs. The lamps often protrude from the bottom of the fixture and the light distribution from the fixture is poor because its optical characteristics suit an incandescent lamp. Another approach: retrofit with a specially designed reflector and lamp holder that maximizes the optics of the CFL and has a more pleasing appearance.

It's a good idea to replace incandescent lamps with compact fluorescents (CFLs). When doing so, the proper ratio is about 3 to 4 incandescent watts to 1 compact fluorescent watt. There may be an aesthetic problem with replacing incandescent lamps with CFLs in "can" fixtures because these fixtures are not designed for CFLs. The lamps often protrude from the bottom of the fixture, and the light distribution from the fixture is poor because its optical characteristics suit an incandescent lamp. Another approach: retrofit with a specially designed reflector and lamp holder that maximizes the optics of the CFL and has a more pleasing appearance.

Switching from traditional light bulbs (called incandescent) to CFLs is an effective, simple change everyone in America can make right now. Making this change will help to use less electricity at home and prevent greenhouse gas emissions that lead to global climate change. Lighting accounts for close to 20 percent of the average home’s electric bill. ENERGY STAR qualified CFLs use up to 75 percent less energy (electricity) than incandescent light bulbs, last up to 10 times longer, cost little up front, and provide a quick return on investment.

If every home in America replaced just one incandescent light bulb with an ENERGY STAR qualified CFL, in one year it would save enough energy to light more than 3 million homes. That would prevent the release of greenhouse gas emissions equal to that of about 800,000 cars

CFLs contain a very small amount of mercury sealed within the glass tubing — an average of 4 milligrams — about the amount that would cover the tip of a ballpoint pen. By comparison, older thermometers contain about 500 milligrams of mercury — an amount equal to the mercury in 125 CFLs. Mercury is an essential part of CFLs; it allows the bulb to be an efficient light source. No mercury is released when the bulbs are intact (not broken) or in use.

Most makers of light bulbs have reduced mercury in their fluorescent lighting products. Thanks to technology advances and a commitment from members of the National Electrical Manufacturers Association, the average mercury content in CFLs has dropped at least 20 percent in the past year. Some manufacturers have even made further reductions, dropping mercury content to 1.4 — 2.5 milligrams per light bulb.

EPA estimates the U.S. is responsible for the release of 104 metric tons of mercury emissions each year. Most of these emissions come from coal fired electrical power. Mercury released into the air is the main way that mercury gets into water and bio accumulates in fish. (Eating fish contaminated with mercury is the main way for humans to be exposed.)

Most mercury vapor inside fluorescent light bulbs becomes bound to the inside of the light bulb as it is used. EPA estimates that the rest of the mercury within a CFL — about 11 percent — is released into air or water when it is sent to a landfill, assuming the light bulb is broken. Therefore, if all 290 million CFLs sold in 2007 were sent to a landfill (versus recycled, as a worst case) — they would add 0.13 metric tons, or 0.1 percent, to U.S. mercury missions caused by humans.

Electricity use is the main source of mercury emissions in the U.S. CFLs use less electricity than incandescent lights, meaning CFLs reduce the amount of mercury into the environment. As shown in the table below, a 13­watt, 8,000­rated­hour­life CFL (60­watt equivalent; a common light bulb type) will save 376 kWh over its lifetime, thus avoiding 4.5 mg of mercury. If the bulb goes to a landfill, overall emissions savings would drop a little, to 4.2 mg. EPA recommends that CFLs are recycled where possible, to maximize mercury savings

Because CFLs also help to reduce greenhouse gasses, other pollutants associated with electricity production, and landfill waste (because the bulbs last longer), they are clearly the environmental winner when compared to traditional incandescent light bulbs.

CFLs are made of glass and can break if dropped or roughly handled. Be careful when removing the bulb from its packaging, installing it, or replacing it. Always screw and unscrew the light bulb by its base (not the glass), and never forcefully twist the CFL into a light socket. If a CFL breaks in your home, follow the cleanup recommendations below. Used CFLs should be disposed of properly (see below).

EPA recommends that consumers take advantage of available local recycling options for compact fluorescent light bulbs. EPA is working with CFL manufacturers and major U.S. retailers to expand recycling and disposal options. Consumers can contact their local municipal solid waste agency directly, or go to http://www.epa.gov/bulbrecycling or http://www.earth911.org to identify local recycling options.

If your state or local environmental regulatory agency permits you to put used or broken CFLs in the garbage, seal the bulb in two plastic bags and put it into the outside trash, or other protected outside location, for the next normal trash collection. Never send a fluorescent light bulb or any other mercury-containing product to an incinerator.

If your ENERGY STAR qualified CFL product burns out before it should, look at the CFL base to find the manufacturer's name. Visit the manufacturer's web site to find the customer service contact information to inquire about a refund or replacement. Manufacturers producing ENERGY STAR qualified CFLs are required to offer at least a two year limited warranty (covering manufacturer defects) for CFLs used at home. In the future, save your receipts to document the date of purchase.

Because CFLs contain a small amount of mercury, EPA recommends the following cleanup and disposal guidelines:

  1. Before cleanup: air out the room:
    • Open a window and leave the room for 15 minutes or more.
    • Shut off the central forcedair heating/air conditioning system, if you have one.
  2. CleanUp steps for hard surfaces:
    • Carefully scoop up glass fragments and powder using stiff paper or cardboard and place them in a glass jar with metal lid (such as a canning jar) or in a sealed plastic bag.
    • Use sticky tape, such as duct tape, to pick up any remaining small glass pieces and powder.
    • Wipe the area clean with damp paper towels or disposable wet wipes. Place towels in the glass jar or plastic bag.
    • Do not use a vacuum or broom to clean up the broken bulb on hard surfaces.
  3. Cleanup steps for carpeting or rug:
    • Carefully pick up glass fragments and place them in a glass jar with metal lid (such as a canning jar) or in a sealed plastic bag.
    • Use sticky tape, such as duct tape, to pick up any remaining small glass fragments and powder.
    • If vacuuming is needed after all visible materials are removed, vacuum the area where the bulb broke.
    • Remove the vacuum bag (or empty and wipe the canister), and put the bag or vacuum debris in a sealed plastic bag.
  4. Cleanup steps for clothing, bedding, etc.:
    • If clothing or bedding materials come in direct contact with broken glass or mercury­containing powder from inside the bulb that may stick to the fabric, the clothing or bedding should be thrown away. Do not wash such clothing or bedding because mercury fragments in the clothing may contaminate the machine and/or pollute sewage.
    • You can, however, wash clothing or other materials that have been exposed to the mercury vapor from a broken CFL, such as the clothing you are wearing when you cleaned up the broken CFL, as long as that clothing has not come into direct contact with the materials from the broken bulb.
    • If shoes come into direct contact with broken glass or mercury­containing powder from the bulb, wipe them off with damp paper towels or disposable wet wipes. Place the towels or wipes in a glass jar or plastic bag for disposal.
  5. Disposal of cleanup materials:
    • Immediately place all clean­up materials outdoors in a trash container or protected area for the next normal trash pickup.
    • Wash your hands after disposing of the jars or plastic bags containing clean­up materials.
    • Check with your local or state government about disposal requirements in your specific area. Some states do not allow such trash disposal. Instead, they require that broken and unbroken mercury­containing bulbs be taken to a local recycling center.
  6. Future cleaning of carpeting or rug: air out the room during and after vacuuming:
    • The next several times you vacuum, shut off the central forced­air heating/air conditioning system and open a window before vacuuming.
    • Keep the central heating/air conditioning system shut off and the window open for at least 15 minutes after vacuuming is completed.

Get rid of mercury lamps inside and outside a building. Their light output reduces over time, and a dim mercury lamp uses as much energy as a brand new one. Replace them with high-pressure sodium or metal halide lamps.

Don't let first cost deter you from investigating some of the more energy-efficient lighting technologies. The most expensive lighting equipment usually consumes the least energy and therefore costs much less to run. The initial cost of a state-of-the-art system may even be lower than the overall cost of a less expensive and less efficient system if you use fewer fixtures to achieve the same or better light levels, and if you can tap into utility rebates and other incentives.

Update a system using energy core-coil ballasts and "watt miser" lamps to a T8 system for further savings.

When retrofitting an existing lighting system, look at the task being performed in the space. In many cases, high overall light levels can be reduced when good task lighting is installed. A combination of good, sensible lighting design with the use of the latest technology lighting systems can result in substantial energy savings and an overall improvement in lighting quality.


Operate well-maintained equipment with properly-trained staff

Ensure that all equipment (old and new) is operated correctly by trained personnel on an ongoing basis. Keeping equipment maintained doesn't cost, it pays.


"Soft starting" refers to reducing the current in the power supply during motor acceleration. Benefits of soft starting include preventing a severe voltage dip when then motor starts and lessening mechanical shock to equipment. Despite the claims of starter suppliers to the contrary, soft starting does not result in reduced energy costs.

Carefully evaluate whether to replace a functioning motor with a more energy efficient one. It is not a good idea to replace motors that run only a few hours per day. Continuously running motors such as those used in the papermaking process are better candidates for replacement. It takes too long to recover the cost of replacement of motors that run less than 4,400 hours per year.

Choose a motor with a sufficient horsepower rate. In general, a motor operates at three fourths of the horsepower shown on its nameplate. For this reason, an oversized motor is often a more efficient way to drive a the load than a smaller motor.

Compare brands and prices of motors based on NEMA value rather than hype. Ignore advertisements and sales promotions that contrast "high efficiency," "premium efficiency," "extra efficient," or "super efficient" motors with "standard efficiency" or "low efficient" ones. Instead, compare the efficiency value stamped on a motor's nameplate to standards published by the National Electrical Manufacturers Association (NEMA).

When troubleshooting problems with a motor, consider what the symptoms are and how long they have been present. Note the changes that occurred in the equipment once the problem began, and evaluate how accurate the evidence of the problem is. Also consider the motor's ratings and its circuitry. Keep track of the specific actions taken to remedy the problem.

What does all the hype mean? You'll see all kinds of ads, sales promotions and technical literature about motors having "high efficiency." These motors may be called "premium efficiency," "extra efficient," even "super efficient." Labels on the motors themselves may use similar wording. Those products are all contrasted with "standard efficiency" or "low efficient." How can a user make sense out of all that? By recognizing a few simple facts. Every National Electrical Manufacturers Association (NEMA) standard polyphase Design B motor below 150 hp (and many of them well above that) has an efficiency value stamped on its nameplate. That's a "nominal" value, representative of that design. For every such value, a "minimum" or guaranteed value is published in NEMA standards. Disregard the fancy labels and catchy slogans-get those numbers. Compare brands-and prices- based on them. Some extra-cost motor lines offer efficiencies far above the NEMA "energy efficient" value; some "standard" motor lines may also reach such high levels for some ratings. Each customer's economic analysis will point toward the best solution.

Based on surveys by the Institute of Electrical and Electronics Engineers (IEEE), the average life of a motor is at least 15 years.

A power factor controller adjusts motor voltage to suit motor load. This device only saves energy on smaller motors; such motors use so little power that the savings is insignificant.

How long should a motor last? Various Institute of Electrical and Electronics Engineers (IEEE) reliability surveys have shown two general life relationships for industrial motors. One is that annual repair/replacement rates for the overall motor population tend to be 5 to 6 percent. That implies a 15- to 20-year average life span. However, these surveys did not make clear what was accepted as "end of life," nor did they indicate what percentage of the "failed" motors went back into service after repair. The other IEEE survey result was that motor starters tended to fail more often than motors themselves. Based on information of that sort, a reasonable approach seems to be to consider average motor life at least 15 years.

Do the savings from the lower motor losses of an energy-efficient motor justify the extra motor cost? The answer depends on the actual number of operating hours during which losses occur. In seeking candidates for improvement in motor efficiency, don't bother with motors that run only a few hours a day (particularly if they're not fully loaded). The payoff will not be there. Better yet are the continuous runners involved with a process such as papermaking. Although it's no magic number, 4,400 hours annually ("half time") is a useful starting point. Below that, payback might be too long. Replace existing motors that haven't failed just to get the high efficiency? That's seldom justified. You won't see the payoff for even 6,000 hours of operation.

The nameplate is a motor's single most important component. NEMA standards require certain information on all AC motor nameplates. The major items any nameplate must display are: 1. Manufacturer type and frame designation. 2. Horsepower output and time rating (e.g., "continuous"). 3. Phase, frequency, and full-load rpm. 4. Voltage and full-load amperes. 5. Code letter indicating locked-rotor kVA (usually a letter from D through K). 6. Design letter (usually B, C or D; unrelated to the code letter). 7. Service factor, if other than 1.0. 8. Maximum ambient temperature and insulation system designation. 9. Nominal full-load efficiency when applicable (required for 1-125 hp, singlespeed, low-voltage, etc.). What's the importance of all this? Without knowing the serial number, for example, the manufacturer probably can't identify the specific design and answer questions about it. Without the frame size designation, no dimensional questions can be answered. The rpm is a must when comparing two motors to drive the same load. Temperature rating defines suitability to different surroundings. The code letter permits prediction of motor starting capability.

When the subject of efficiency comes up, motor users usually get this advice: "Get rid of those oversized motors. Replace them with motors rated closer to the actual load horsepower, and you'll save energy." On the surface, that seems to make sense. We're used to thinking of a "mismatch" as bad. Suiting components to each other, having their ratings alike, must be better. But motor efficiency doesn't behave that way. In general, it has a maximum or peak value for any motor (whether standard or "energy efficient") at three-fourths of the nameplate horsepower rating. Because of that relationship, an oversized motor is often a more efficient way to drive the load than a smaller motor more nearly matching the required horsepower.

Do "power factor controllers" save energy? "Power factor controller" is a confusing term. Often called a Nola device, it isn't really intended to govern power factor as such. Rather, it electronically adjusts motor voltage to suit motor load, using the motor power factor as an indicator of that load. The device works, but it seldom pays off. When a motor runs fully loaded, its internal power loss is mostly "copper loss" caused by current flow through the windings. If motor voltage is lowered, current must go up to supply the same shaft output; copper loss goes up too, and efficiency tends to drop. In contrast, a lightly loaded motor's internal loss is mostly magnetic loss in the core iron. That drops rapidly when voltage is lowered. Little shaft output is needed, so the reduction does no harm. Net losses go down, and efficiency rises. Total loss can be cut 10, 20, even 50 percent-but the actual watts involved are quite low compared to full-load operation. Unless shaft output averages one-third of rated power, or less, the Nola device normally isn't cost effective-repeated tests confirm just that for three-phase motors of all sizes. The loss picture is different, and the savings greater, for small single-phase motors. But such motors use so little power anyway that the total savings is also small.

For starters, what is motor soft starting? There's no industry standard. Many think of a "soft starter" as an electronic solid-state device for reducing motor voltage (and current draw) during startup. But there's no difference in principle between that and any other "reduced-voltage starting" method autotransformer, series reactor, and so forth. Each reduces the current (and therefore the voltage drop) in the power supply system during motor acceleration. Whatever the type of starter used, two benefits result. One is the mitigation of a severe voltage dip on the system when the motor starts. System limitations or utility rules may require this. A second benefit-though unimportant in some drives-can be the reduced mechanical shock to equipment resulting from lower accelerating torque. Starter suppliers sometimes say that a third benefit is reduced energy cost. Reduced starting current supposedly means the motor "consumes less power." This is untrue. Accelerating a load consisting only of pure inertia requires the expenditure of a fixed amount of energy within the motor. At reduced voltage and current, the acceleration takes longer- but the energy expended is the same.

Study the nameplate on a motor for important information required by the National Electrical Manufacturers Association (NEMA). Key items shown on the label include serial number, frame size designation, RPM, temperature rating, and code letter.

  • What exactly are the symptoms? Measured conditions-how much (or little), how often, what, when, where-are the details needed.
  • How long has this particular trouble been occurring-just started this week, or has been happening on and off for years?
  • No matter how seemingly insignificant, what changes in equipment, operations or maintenance practices took place about the same time the troubles began?
  • How accurate is the evidence of trouble? If meters were used, what kind were they, and how were they connected?
  • What are the ratings-nameplate voltage, current, etc.-of all components involved in the problem (e.g., motors, contactors, fuses, circuit breakers)? Don't assume that the equipment voltage rating matches the circuit.
  • What's the circuitry involved? Is a three-phase transformation open delta or open wye rather than a full set of three transformers? If a motor trips off unexpectedly, or won't start, just how is it controlled? Basic one-line and schematic diagrams should be available showing how things are today, not as they were long ago.
  • What specific actions have been taken to correct the trouble? What were the results?

Turn off computer equipment and copiers when they're not in use

Encourage employees to turn off computers, monitors, printers, and copiers when they are not being used. Consider equipping computers with devices that turn them off automatically after a set period of inactivity. Turning off a typical personal computer during non-working hours saves about $75 per year in energy costs.


Build your own conservation program

There are three ways in which lighting energy use can be reduced by building owners: implement a greater degree of control over the use of lighting, use more efficient lighting equipment and apply better lighting system design strategies. Translated into a general guide, the goals statement for a comprehensive lighting energy conservation program should read: turn it off when it isn't needed; use the most efficient, suitable equipment; and provide light only where it is needed.

Consider the cost of energy when retrofitting lighting systems

When considering lighting system retrofits, remember that the least expensive part of the system on a life-cycle basis is the fixture and lamp. The most expensive component is the energy that the system uses.

Don't think about first cost only!

Don't let first cost deter you from investigating some of the more energy-efficient lighting technologies. The most expensive lighting equipment usually consumes the least energy and therefore costs much less to operate. The initial cost of a state-of-the-art system may even be lower than the overall cost of a less expensive and less efficient system if you use fewer fixtures to achieve the same or better light levels, especially if there are utility rebates and other incentives.

Replace inside and outside mercury lamps

Get rid of mercury lamps inside and outside a building. Their light output reduces over time, and a dim mercury lamp uses as much energy as a brand new one. Replace them with high-pressure sodium or metal halide lamps.

Replace mercury lamps

Get rid of all mercury lamps inside or outside the building! Replace with high-pressure sodium (HPS) or metal halide lamps. These lamps have a higher efficacy (efficiency) than mercury lamps. A 400-watt mercury lamp is rated at about 47 lumens/watt, whereas the same size metal halide lamp is rated at 64 lumens/watt and a similar HPS lamp is rated at 112 lumens/watt. Also, mercury lamps have extremely long lives, but light output reduces drastically as lamps get older. A dim mercury lamp costs as much in energy as a brand new one to operate.

The lowest cost lighting isn't usually the lowest purchase price

Don't let first cost deter you from investigating some of the more energy-efficient lighting technologies. The most expensive lighting equipment usually consumes the least energy and therefore costs much less to run. The initial cost of a state-of-the-art system may even be lower than the overall cost of a less expensive and less efficient system if you use fewer fixtures to achieve the same or better light levels, and if you can tap into utility rebates and other incentives.

Use life-cycle costs to make decisions

When considering lighting system retrofits, remember that the least expensive part of the system on a life-cycle basis is the fixture and lamp. The most expensive component is the energy that the system uses. That is why fluorescent lamps are usually much less expensive over the life of the lamp than incandescent.


Increase the size of distribution piping, or add parallel pipes

The wider a pipe's diameter the less energy is required to move water or air through it. During renovation or expansion, consider increasing the size of distribution piping, or add parallel pipes to double the cross sectional area of the flow path.

Insulate pipes

Insulate exposed, hot-water, steam and chilled-water distribution piping where feasible.

Select piping insulation based on both minimum and maximum temperatures

Select piping insulation based on both minimum and maximum temperatures. Insulation designed only for high temperature piping (high R-value material) contains no vapor barrier, making it unsuitable for piping that also carries chilled water. Moisture building up in insulation destroys its insulating properties and can damage pipes.


Trim the pump impeller in the cooling plant's distribution system

Trim the pump impeller to deliver the specified gallons per minute per ton of water through the cooling plant's distribution system.

Use pumps to reduce pressure losses in the distribution system of the cooling plant

Use pumps to reduce pressure losses in the distribution system of the cooling plant. Eliminate unnecessary valves and other flow restrictors. Also open the balancing valves at the pump.


Add roof insulation

One of the most cost-effective energy conservation measures available is to add roof insulation, including a vapor barrier, when you're replacing a roof. Whether the project is a 19th century historic property with a lead-coated copper roof or a flat-roofed industrial building from the 1930s, the cost of adding insulation results in a rapid payback.


Consider making hot water from boiler stacks

If there is a need for process heat within an operation, a heat reclaimer can be installed in the boiler stack instead of an economizer. A heat reclaimer is similar to an economizer in construction and installation. However, reclaimed heat is used to heat a fluid other than feedwater. This heated fluid then may be used in some other process. Process water is passed through the reclaimer to recover the heat in the exhaust gases. Because of the high temperature rise possible in the process water, the amount of heat transferred with the reclaimer can be considerably greater than with an economizer. Exhaust recovery systems and economizers should be used only when the stack temperature exceeds 350°F. If the stack temperature is allowed to fall below this level, corrosive fluids may condense and damage the stack and possibly the boiler.

Increase water heating system efficiency

Although a hot-water system accounts for only about 4 percent of a building's total energy consumption (that figure is higher in buildings having a laundry or restaurant), increasing the system's energy efficiency is nonetheless worthwhile. The heater's energy efficiency can be raised; the storage tank, supply piping and recirculating piping can be insulated to reduce energy losses due to radiation, convection and conduction; water temperature guidelines can be strictly observed; and tenants can be encouraged to conserve. Energy savings can be achieved by placing water heaters close to usage points rather than installing one central generation tank and long runs of hot-water piping. To determine whether the installation of local units would be advantageous, analyze the building's hot water demand patterns. Next, estimate the existing system's total energy losses; then calculate the local units' potential savings. The energy saved is the sum of the reduced distribution losses and the increase in the average generation efficiency of local units, as compared to a central system.

Install a pressure-reducing valve when water pressure exceeds 40 to 50 pounds

When water pressure exceeds 40 to 50 pounds, consider having a plumber install a pressure-reducing valve on the main service. This valve will restrict the amount of hot water that flows from a tap.

Raise hot-water system efficiency

To save energy, raise the efficiency of the hot-water system by employing several strategies. Insulate the storage tank, supply piping, and recirculation piping; observe water temperature guidelines; encourage the tenants to conserve. In addition, an analysis of a building's hot water demand pattern sometimes indicates that placing multiple water heaters close to usage points is more economical than using one central tank.

Reduce the water pressure

If water pressure exceeds 40 to 50 pounds, consider having a plumber install a pressure-reducing valve on the main service to restrict the amount of hot water that flows from a tap.

Use a heat reclaimer rather than an economizer for process heat

For process heat, install a heat reclaimer rather than an economizer, in the boiler stack. The amount of heat transferred by the reclaimer can be considerably greater than by an economizer. Note: The stack temperature must exceed 350°F to safely use either a heat reclaimer or economizer.


Design and place windows based on internal wall characteristics

The type of internal walls used in your facilities should influence the design and placement of windows. Highly reflective--but not glossy--light-colored walls spread daylight back from the sidewalls. Jewel-toned walls absorb more light and may require more supplemental lighting sources.

Use insulation in aluminum frame windows

Properly insulating your aluminum frame windows makes them almost as energy-efficient as wooden ones. Include an insulating section (thermal break) between the inner and outer aluminum sections of the frames.

Use interior window treatments

In addition to being attractive, interior window treatments reduce energy consumption. Use insulating vertical or horizontal blinds and/or draperies to reduce heat loss and solar gain through window openings.

Use proper U-value in replacement windows

When replacing windows, use windows with a 0.46 U-value or better that has optical properties appropriate for building use. (U-0.46 is a Low-E window in an improved metal frame.)

Use solar control glass

In all but the most northern climates, the use of solar control glass provides significant energy savings. Solar heat gain is a serious problem particularly in buildings with large areas of south-facing glass. In warmer climates in buildings with more than 25 percent glass, consider using window tints or reflective coatings to reflect up to 90 percent of the solar heat striking windows.

Use window films

Window films help reduce air conditioning and heating energy use while allowing occupants to enjoy the view. In optimum situations, energy savings frequently pay back the cost of film installation in a year or less.