1. Change your air filter regularly
Check your filter every month, especially during heavy use months (winter and summer). If the filter looks dirty after a month, change it. At a minimum, change the filter every 3 months. A dirty filter will slow down air flow and make the system work harder to keep you warm or cool — wasting energy. A clean filter will also prevent dust and dirt from building up in the system — leading to expensive maintenance and/or early system failure.
2. Tune up your HVAC equipment yearly
Just as a tune-up for your car can improve your gas mileage, a yearly tune-up of your heating and cooling system can improve efficiency and comfort. Learn more: Maintain your Equipment: A Checklist Finding the right contractor: 10 tips
3. Install a programmable thermostat
A programmable thermostat is ideal for people who are away from home during set periods of time throughout the week. Through proper use of pre-programmed settings, a programmable thermostat can save you about $150 every year in energy costs.
4. Seal your heating and cooling ducts
Ducts that move air to-and-from a forced air furnace, central air conditioner, or heat pump are often big energy wasters. Sealing and insulating ducts can improve the efficiency of your heating and cooling system by as much as 20 percent — and sometimes much more. Focus first on sealing ducts that run through the attic, crawlspace, unheated basement, or garage. Use duct sealant (mastic) or metal-backed (foil) tape to seal the seams and connections of ducts. After sealing the ducts in those spaces, wrap the ducts in insulation to keep them from getting hot in the summer or cold in the winter. Next, seal ducts that you can access in the heated or cooled part of the house. See our Duct Sealing Brochure[/button] (1.13MB) for more information.
5. Consider installing ENERGY STAR qualified heating and cooling equipment
If your HVAC equipment is more than 10 years old or not keeping your house comfortable, you should have it looked at by a professional HVAC contractor. If it is not performing efficiently or needs upgrading, consider replacing it with a unit that has earned the ENERGY STAR. Installed correctly, these high-efficiency heating and cooling units can save up to 20 percent on heating and cooling costs. But before you invest in a new HVAC system, make sure that you have addressed the big air leaks in your house and the duct system. Sometimes, these are the real sources of problems rather than your HVAC equipment. Remember that getting the proper size and a quality installation is essential to getting the most from your new equipment. When replacing HVAC equipment, bigger doesn’t always mean better. If the unit is too large for your home, you will be less comfortable and might actually have higher utility bills. Oversized equipment will operate in short run cycles, not allowing the unit to reach efficient operation and remove humidity from the air — resulting in an uncomfortable home. Your contractor should determine the right size for your HVAC equipment by using ACCA/ANSI Manual J or an equivalent sizing calculation tool that takes into account specific information about your home.
Estimated energy consumption on a scale showing a range for similar models
Estimated yearly operating cost based on the national average cost of electricity.
Home Energy Saver- Web-based do-it-yourself energy audit tool (Lawrence Berkely National Laboratory)
Heating and Cooling Equipment Research & Development- Oak Ridge National Laboratory
Consumer Guide to Home Energy Savings- American Council for an Energy-Efficient Economy (ACEEE)
Residential Natural Gas Prices- Energy Information Administration (EIA) – Official Energy Statistics from the U.S.Government
Residential Electricity Prices- Energy Information Administration (EIA) – Official Energy Statistics from the U.S.Government
Residential Heating Oil Prices- Energy Information Administration (EIA) – Official Energy Statistics from the U.S.Government
Propane Prices- Energy Information Administration (EIA) – Official Energy Statistics from the U.S.Government
Heat Pump Tips
Air-Source Heat Pumps
|>= 8.2 HSPF/ >=14 SEER/ >=11.5 EER* for split systems>= 8.0 HSPF/ >=14 SEER/ >=11 EER* for single package equipment including gas/electric package units|
|Central Air Conditioners||>=14 SEER/ >=11.5 EER* for split systems>=14 SEER/ >=11 EER* for single package equipment including gas/electric package units|
*Energy Efficiency Ratio
An air-source unitary heat pump model consists of one or more factory-made assemblies which normally include an indoor conditioning coil(s), compressor(s), and outdoor coil(s), including means to provide a heating function. ASHPs shall provide the function of air heating with controlled temperature, and may include the functions of air-cooling, air-circulation, air-cleaning, dehumidifying or humidifying.
A central air conditioner model consists of one or more factory-made assemblies which normally include an evaporator or cooling coil(s), compressor(s), and condenser(s). Central air conditioners provide the function of air-cooling, and may include the functions of air-circulation, air-cleaning, dehumidifying or humidifying.
This is a measure of a heat pump’s energy efficiency over one heating season. It represents the total heating output of a heat pump (including supplementary electric heat) during the normal heating season (in Btu) as compared to the total electricity consumed (in watt-hours) during the same period. HSPF is based on tests performed in accordance with ARI 210/2401.
This is a measure of equipment energy efficiency over the cooling season. It represents the total cooling of a central air conditioner or heat pump (in Btu) during the normal cooling season as compared to the total electric energy input (in watt-hours) consumed during the same period. SEER is based on tests performed in accordance with ARI 210/2401.
This is a measure of the instantaneous energy efficiency of cooling equipment. EER is the steady-state rate of heat energy removal (e.g., cooling capacity) by the equipment in Btuh pided by the steady-state rate of energy input to the equipment in watts. This ratio is expressed in Btuh per watt (Btuh/watt). EER is based on tests performed in accordance with ARI 210/2401.
1Air-Conditioning and Refrigeration Institute. Standard 210/240“2003 Standard for Unitary Air-Conditioning and Air-Source Heat Pump Equipment.”
A variety of energy ratings now abound, which can be confusing to the consumers these ratings were intended to help. We will try here to end that confusion by explaining each of the ratings systems listed below in as simple a way as possible. Also included is a Glossary of Efficiency Terms.
The materials from which a building is constructed can have a marked impact on the structure’s efficiency. Materials that allow a lot of heat to pass through them lower the overall efficiency level of the building. Conversely, materials that resist a significant amount of heat transference can help ensure greater efficiency. The degree to which a building component (such as a window or wall system) transfers heat is referred to as its U-value. The ability of an inpidual material (for instance, glass, wood, metal) to resist heat transfer is called its R- value.
When referring to the efficiency of an appliance or energy system, we are actually talking about how much energy that system must use to perform a certain amount of work. The higher its energy consumption per unit of output, the less efficient the system is. For example, an air conditioner that requires 750 watts of electricity to provide 6,000 Btu of cooling will be less efficient than one that can provide the same amount of cooling for only 500 watts. The most common ratings applied to energy systems are EER and SEER for most central cooling systems; COP for some heat pumps and chillers; HSPF for heat pumps in their heating modes; and AFUE for gas furnaces and boilers.
For more detailed explanations of the efficiency terms mentioned above, select any of the underlined topics below.
AFUE (annual fuel utilization efficiency):an efficiency rating that measures the efficiency with which gas and other fossil-fuel-burning furnaces and boilers use their primary fuel source over an entire heating season. It does not take into account the efficiency with which any component of the system, such as a furnace fan motor, uses electricity. AFUE is expressed as a percentage that indicates the average number of Btu worth of heating comfort provided by each Btu worth of gas (or other fossil fuel) consumed by the system. For instance, a gas furnace with an AFUE of 80% would provide 0.8 Btu of heat for every Btu of natural gas it burned.
When comparing efficiencies of various gas furnaces, it is important to consider the AFUE, not the steady state efficiency. Steady state refers to the efficiency of the unit when the system is running continuously, without cycling on and off. Since cycling is natural for the system over the course of the heating season, steady state doesn’t give a true measurement of the system’s seasonal efficiency. For instance, gas furnaces with pilot lights have steady-state efficiencies of 78% to 80%, but seasonal efficiencies B AFUEs B closer to 65%.
Virtually all gas forced-air furnaces installed in this area from the 1950s through the early 1980s had AFUEs of around 65%. Today, federal law requires most gas furnaces manufactured and sold in the U.S. to have minimum AFUEs of 78%. (Mobile home furnaces and units with capacities under 45,000 Btu are permitted somewhat lower AFUEs.) Gas furnaces and boilers now on the market have AFUEs as high as 97%
Air infiltration: the introduction, usually unintentional, of unconditioned outdoor air into a mechanically heated and/or cooled building. Air infiltration can occur through any opening in the home’s structure, including seams where walls meet other walls, window or door frames, or chimneys; holes where wires or pipes penetrate walls, floors or ceilings/roofs; and between the loose-fitting meeting rails of double-hung windows or a door door bottom and door threshold. It is one of the major cause of unwanted heat gain and loss and personal discomfort in buildings.
Btu (British thermal unit): a measurement of the energy in heat. It takes one Btu of heat to warm one pound of water by 1° Fahrenheit. Btu can be used either to define an air conditioner’s cooling capacity (i.e., the number of Btu of heat that can be removed by the system) or a furnace’s heating capacity (i.e., the number of Btu of heat that can be supplied by the system).
Caulk: a substance used to seal air infiltration points between two immovable objects, such as where exterior or interior wall surfaces meet window or door frames and at corners formed by siding. Most caulks come in tubes and are applied with the use of a special caulk “gun.”
Compact fluorescent lamps (CFLs): a light “bulb” using fluorescent technology but designed to be used on many of the same fixtures traditionally used by standard incandescent “A” bulbs. They incorporate a small-diameter looped or swirled tube that is attached to a screw-in base. CFLs provide light levels comparable to 20- to 150-watt incandescent bulbs for 70% to 75% less energy. They also last 10 to 13 times longer than equivalent incandescent bulbs.
Conduction: the transfer of heat through solid objects such as glass, dry wall, brick and other building materials. The greater the difference between the outdoor and indoor temperatures, the faster conduction can occur and the more home a building can gain or lose.
Convection: the transfer of heat to or from a solid surface via a gas or liquid current. Where home heat loss and gain are concerned, heat convection is caused by air (gas) currents that carry heat from your body, furniture, interior walls and other warm objects to windows, floors, ceilings, exterior walls and other cool surfaces.
COP(coefficient of performance): a measurement of a heat pump’s efficiency (in the heating mode) at a specific outdoor temperature – usually 47°F. A COP of 1 indicates that for each unit of energy being used, an equal amount of energy, in the form of heat) is being provided by the system. A heat pump with a COP of 3 would provide three times as much energy in heat as it consumes in electricity at an outdoor temperature of 47°F. COP is also sometimes used to measure the single temperature cooling efficiency of chillers.
This formula is stated:
Btu of heat produced at 47°F
Btu worth of electricity used at 47°
For instance, let’s assume a heat pump uses 4000 watts of electricity to produce 42,000 Btu per hour (Btu/hr) of heat when it is 47°F outside. To determine its COP, you would first convert the 4000 watts of electrical consumption into its Btu/hr equivalent by multiplying 4000 times 3.413 ( the number of Btu in one watt-hour of electricity). Then you would pide your answer — 13,648 Btu/hr — into the 42,000 Btu/hr heat output. This would show your heat pump to have a 47°F COP of 3.08. This means that, for every Btu of electricity the system uses, it will produce a little more than three Btu of heat when the outdoor temperature is 47°F.
The second formula is most frequently used to determine chiller efficiency. Using this calculation method, you would pide 3.516 by the number of kilowatts (kW) per ton used by the system. This formula is stated:
For example, a chiller that consumes 0.8 kW per ton of capacity would have a COP of 4.4 (3.516 pided by 0.8). On the other hand, the COP of a new, more efficient chiller, using as little as 0.5 kW per ton, would be greater than 7 (3.516 pided by 0.5).
Daylighting: the technique of using natural light from windows, skylights and other openings to supplement or replace a building’s artificial lighting system. When applied properly, daylighting can reduce a facility’s lighting costs. When applied improperly, however, it can not only lead to inappropriate light levels but can also raise the building’s cooling costs by introducing high levels of solar heat into the interior of the building.
Dedicated fixture: a lighting apparatus that is designed specifically for use with a particular type of lamp (bulb). For example, the increasing popularity of CFLs has led to the development of a growing number of fixtures – including torchieres, table lamps, ceiling drums, and recessed canisters – dedicated solely for use with compact fluorescents.
EER (energy efficiency ratio): a measurement of the energy required by a cooling system as it attempts to maintain indoor comfort at a specific outdoor temperature – usually 95°F. The term EER is most commonly used when referring to window air conditioners and geothermal heat pumps. EER equals the number of Btu per hour worth of cooling provided at the specified outdoor temperature pided by the number of watts used to provide that level of cooling.
Btu/hr of cooling at 95°
watts used at 95°
For instance, if you have a window air conditioner that draws 1500 watts of electricity to produce 12,000 Btu per hour of cooling when the outdoor temperature is 95°, it would have an EER of 8.0 (12,000 pided by 1500). A unit drawing 1200 watts to produce the same amount of cooling would have an EER of 10 and would be more energy efficient.
Using this same example, you can see how efficiency can affect a system’s operating economy. First, you’ll need to determine the total amount of electricity — measured in kilowatt-hours — the unit will consume over a period of time. (A kilowatt-hour is defined as 1,000 watts used for one hour. This is the measure by which your monthly utility bills are calculated.) To do this, let’s assume you operate your 8 EER window air conditioner — drawing 1500 watts at any given moment — for an average of 12 hours every day during the summer. At this rate, it will use 18,000 watt-hours, or 18 kilowatt-hours (kWh) each day, leading to a total consumption of 540 kWh over the course of a 30-day month. At a summer electric rate of 6.34¢ per kWh, it would cost you $34.24 to operate that window air conditioner each month. At the same time, a 1200-watt, 10 EER system, consuming 14.4 kilowatt-hours per day and 432 kWh per month, would cost you $27.39, a 20% savings over the less efficient model.
Efficiency: the degree to which a certain action or level of work can be effectively produced for the least expenditure of effort or fuel. For instance, a light bulb that uses 15 watts of electricity to produce 900 lumens of light would operate with much greater efficiency than one that required 60 watts to produce the same light level.
HSPF (heating seasonal performance factor): a measurement of an all-electric air-to-air heat pump’s efficiency (in the heating mode) over an entire season. HSPF is calculated by piding the total number of Btus of heating provided over the entire season by the total number of watt-hours required to operate the system over the season.
Btu of heat produced over the heating season
watt-hours of electricity used over the heating season
Most heat pumps installed in Springfield today have HSPFs in the 7.0 to 8.0 range, meaning they operate with seasonal efficiencies of anywhere from 205% to 234%. (To convert the HSPF number into a percentage, you just pide the HSPF by 3.414, the number of Btu in one watt-hour of electricity.) That means that, for every Btu-worth of energy they use over the entire heating season, these systems will put out anywhere from 2.05 to 2.34 Btu of heat. Compare this to electric furnaces, which have nominal efficiencies of 100% (for each Btu worth of electricity, they put out one Btu of heat), or new gas furnaces, which have efficiency ratings of about 80% to 97% (for each Btu worth of gas, they put out 0.8 to 0.97 Btu of heat).
NOTE:When comparing energy systems that use different primary fuel sources with different costs per Btu, it is important that you understand that higher operating efficiency is not necessarily equivalent to better operating economy. Although an electric heat pump might work with greater efficiency than a gas furnace, it won’t necessarily be more economical to run due to the pricing difference between the two fuel sources.
Insulation: a product that inhibits conductive and convective heat transfer. Some materials are naturally better insulators than others because they contain more “dead air” pockets. These pockets of trapped gas help to slow the movement of heat. However, if processed properly, virtually any product, including glass, cotton, paper, and plastic, can be used to make insulation.
Internal Heat Gain: the accumulation of heat produced by a building’s energy systems and appliances and occupants. Depending on the number of occupants and the type and number of energy systems used during the day, it’s not unusual for internal heat gain to account for 20% of a home’s total summer cooling load.
Kilowatt-hour (kWh): 1000 watts used for one hour – or any combination of energy multiplied by time that is equivalent to that rate of electrical consumption, such as one watt used for 1000 hours, 10 watts used for 100 hours, or 50 watts used for 20 hours. For example, a 100-watt light bulb left on for five hours each day would consume one kWh every two days. Kilowatt-hour is the primary measure on which U.S. electric companies base most customer billing. CWLP residential customers pay an average of 5.5¢ to 6¢ per kWh of electricity used.
Low-e: refers to a material designed to reduce the amount of radiant heat that can be transferred through glass or other translucent window coverings. Low-e (which stands for low-emissivity) coatings or films have the ability to re-radiate a high percentage of heat back toward its source. In summer low-e windows can be effective in reducing the amount of solar heat that can enter a house, and in winter they can reduce the amount of furnace-generated heat that can be lost to the outdoors.
Payback period: the amount of time it takes to achieve a full return on an investment. For instance, if a high-efficiency air conditioner would cost you $300 more to purchase than a lower-efficiency model but would save you $100 a year in operating costs, your payback period on the extra $300 investment would be three years.
Radiation: a method of heat transfer in which heat is transmitted from surface to surface via infrared waves. Radiant heat warms the surfaces it touches without increasing the temperature of the air through which it travels. All warm bodies radiate infrared energy.
Return on investment (ROI): the annual rate at which an investment earns income. It is calculated by piding the annual earnings by the investment. For instances, a bank savings account paying $3 per year per $100 investment has an ROI of 3% ($3 / $100). An efficiency investment’s ROI comes not from money paid to you, but rather from money saved by you on your energy bills.
R-value:a measurement of a material’s ability to resist heat transfer. Insulation products are rated according to the R-value. The higher its R-value, the greater the product’s ability to resist heat flow will be.
Some materials are more resistant to heat transfer than others, giving them higher R-values. One of the best ways to enhance the product’s R-value is to increase the amount of gas (including air) inside or immediately surrounding it. For instance, the glass of a single-pane window has virtually no R-value, but the thin film of air that normally exists on either side of the glass gives the window an R-value of about 0.83. Adding a second pane of glass and sealing the space between the panes will increase the thickness of one of the insulating gas layers, thereby more than doubling the window’s R-value.
Another example of how the presence of dead-air spaces affect a product’s R-value can be seen with wood. Hard woods, like oak, typically have an insulating value of R-1 per inch of thickness. However, softer woods, such as pine, might have R-values twice as high due to their greater number of air-filled pores.
Products developed especially for the purpose of impeding unwanted heat transfer are called insulation. Insulation can be made of a variety of materials, including old newspapers and wood fibers, glass fibers, and synthetic foams. It can also come in a variety of configurations, including soft blankets, rigid boards, or fluffy granular loose-fill, but what they all have in common, is their abundance of air-filled pores or pockets.
The actual R-value of insulation products can vary greatly, depending on their composition and form. The least resistant and least common are perlite and vermiculite loose-fills, at R-2.2 to R-2.7 per inch of thickness; the most resistant are polyisocyanurate rigid boards, at R-7 per inch of thickness. Fiberglass blankets and cellulose loose-fills, two of the most common residential insulations have R-values of 3.1 to 3.7 per inch.
SEER (seasonal energy efficiency ratio): a measurement of how energy efficient a central cooling system can operate over the course of an entire cooling season. This term is most often applied to central air-to-air heat pumps (in the cooling mode) and air conditioners. SEER is expressed as the pidend of the number of Btu of cooling provided over the season pided by the total number of watt-hours the system consumes. Federal law requires all central split systems now made and sold in the United States to have minimum SEERs of 10. Effective January 2006, the minimum for most systems will increase to 13.
seasonal Btu of cooling
seasonal watt-hours used
By federal law, every central split cooling system manufactured or sold in the U.S. today must have a seasonal energy efficiency ratio of at least 10.0.
Settled density: the amount (depth) of insulation remaining after it has had a chance to settle. This term is most often applied to loose-fill insulations—particularly those made of cellulose. To ensure loose-fill cellulose insulation will maintain its desired insulating value (r-value) once it has settled, you will need to install it to a depth that is 20% to 25% deeper than your settled density r-value actually calls for.
Solar Gain: heat that builds up inside a structure as a result of sunlight that enters through transparent or translucent surfaces, such as windows, and is converted to heat after striking other surfaces inside the building. In summer, solar gain can cause as much as 50% of the interior heat gain in a home.
Thermostat Setback: an intentional effort to control building energy consumption by manually or automatically controlling thermostat settings according to the amount of cooling or heat that is needed at any given time of the day or night.
U-value: the measurement of how readily heat can flow through glass, brick, drywall and other building materials. U-values, which are expressed in decimals(e.g., U-0.166), are the opposite of R-values. The higher the U-value, the less efficient the building material will be.The lower a material’s U-value, the higher its R-value will be.
To determine the R-value of a product for which the U-value is given, you first convert the U-value to its equivalent fraction and then invert it. For instance, the equivalent fraction of U-0.166 would be 166/1000 or 1/6. This inverts to 6/1 or 6, giving you an R-value of 6.
For most consumers, U-value is likely to be of concern only when shopping for new windows, where efficiency is frequently stated in terms of U-value rather than R-value.
Vapor barrier: a material designed to resist the migration of moisture through a wall or other building component. As water vapor in the air moves from a warmer to a cooler part of the building it can settle and condense on cooler building components, such as rafters, beams and walls, eventually causing those components to mildew, rust or rot. Vapor barriers, which are impermeable to water vapor migration, help to protect against this possibility. The most common vapor barriers are made of plastic, but other materials, including oil paint, can also serve the purpose.
Remember, saving energy prevents pollution. By choosing ENERGY STAR and taking steps to optimize the performance of your heating and cooling equipment, you are helping to prevent global warming and promoting cleaner air while enhancing the comfort of your home.
You may also be interested to know:
The clothes dryer is typically the second-biggest electricity-using appliance after the refrigerator, costing about $85 to operate annually. A typical clothes dryer will cost $1,100 to operate over its lifetime. Some new clothes dryers remove moisture more efficiently, have moisture sensors, and have automatic shut-off controls to avoid over-drying.
Dryers work by heating and aerating clothes. The efficiency of a clothes dryer is measured by a term called the energy factor. It is somewhat similar to the miles per gallon for a car, but in this case the measure is pounds of clothing per kilowatt-hour of electricity. The minimum rating for a standard capacity electric dryer is 3.01. For gas dryers the minimum energy factor is 2.67. The rating for gas dryers is provided in kilowatt-hours though the primary source of fuel is natural gas.
Unlike most other types of appliances, energy consumption does not vary significantly among comparable models of clothes dryers. Clothes dryers are not required to display EnergyGuide labels.
From: U.S. Department of Energy, Office of Public and Consumer Affairs, Consumer and Public Liaison, Energy Information Administration (10/95).
Answers follow the questions:
1. For which jobs are microwave ovens used most?
Defrosting frozen foods
2. Microwave ovens are currently found in what percentage of all U.S. Homes?
3. Almost all of us use ovens for cooking. What percentage are electric?
4. How many gallons of hot water does the typical dishwasher use during a normal cycle?
5. Ceiling fans are currently found in what percentage of U.S. homes?
10 to 15%
25 to 30%
50 to 55%
6. Switching to fluorescent lighting can save consumers a lot of money. How much money could Americans save collectively each year if we all made the switch to efficient lighting?
$ 1 million
7. Energy-efficient lighting can reduce home electricity demand up to what percent?
8. In a family of four, if each member takes one 10-minute shower a day using a standard showerhead, how many gallons of water will the family use a year?
9. How much does the typical family spend in a year to run its electric home appliances?
$100 to $300
$400 to $1,000
$1,100 to $1,500
10. How many gallons of gasoline does a typical driver use each year?
11. What percent of home heat is lost up an open chimney flue after a fire has died in the fireplace?
12. Industry consumes what percent of the total energy used in the United States?
13. Which renewable energy source generates the most electricity?
14. What energy source provides more than half of the electricity in the U.S.?
15. What is the nation’s most plentiful energy source?
1. Cooking meals
4. 14 gallons
5. 50 to 55%
6. $750 million
8. 73,000 gallons
9. $400 to $1,000
Heating and cooling your home uses more energy and drains more energy dollars than any other system in your home. Typically, 44% of your utility bill goes for heating and cooling. No matter what kind of heating, ventilation and air-conditioning system you have in your house, you can save money and increase comfort by properly maintaining and upgrading your equipment. Remember, though, an energy efficient furnace or air-conditioner alone will not have as great an impact on your energy bills as using the whole house approach. By combining proper equipment maintenance and upgrades with appropriate insulation, weatherization and thermostat setting, you can cut your energy bills in half.
All major appliances including gas furnaces, boilers, air conditioners and heat pumps sold in California meet the Title-24 energy efficiency “standards.” If you are thinking about purchasing a new central furnace, please check out our Appliance Database that lists the most energy-efficient models. This database will eventually be interactive allowing you to compare models.
If you use electricity to heat your home, consider installing an energy efficient heat pump system. Heat pumps are the most efficient for of electric heating in moderate climates, providing three times more heating than the equivalent amount of energy they consume in electricity. There are three types of heat pumps: air-to-air, water source and ground source. They collect heat from the air, water or ground outside your home and concentrate it for use inside. Heat pumps do double duty as a central air conditioner. They can also cool your home by collecting the heat inside your house and effectively pumping it outside. A heat pump can trim the amount of electricity you use for heating as much as 30% to 40%.
Heat Pump Tips
Gas and Oil Systems
Gas furnaces are rated for efficiency with an Annual Fuel Utilization Efficiency number, or an AFUE. According to the state’s Energy Efficiency Standards, Title 24, the minimum AFUE for central furnace systems now sold in California is 0.78, which means that 78 percent of the fuel used by the furnace actually reaches your home’s duct work as heat.
The higher the AFUE, the more efficient the furnace. AFUE numbers in today’s furnaces range from 0.78 to around 0.90. If you are thinking about purchasing a new central furnace, please check out our Appliance Database that lists the most energy-efficient models.
Gas Furnace Tips
It might surprise you to know that buying a bigger room air-conditioning unit won’t necessarily make you feel more comfortable during the hot summer months. In fact, a room air conditioner that’s too big for the area it is supposed to cool will perform less efficiently and less effectively than a smaller, properly sized unit. This is because room units work better if they run for relatively long periods of time than if they are continually, switching off and on. Longer run times allow air conditioners to maintain a more constant room temperature. Running longer also allows them to remove a larger amount of moisture from the air, which lowers humidity and, more importantly, makes you feel more comfortable.
Sizing is equally important for central air-conditioning systems, which need to be sized by professionals. If you have a central air system in your home, set the fan to shut off at the same time as the cooling unit (compressor). In other words, don’t use the system’s central fan to provide circulation but instead use circulating fans in individual rooms.
SEER is the Seasonal Energy Efficiency Rating. SEER rates the efficiency during the cooling season. Look for a SEER rating of 13 or above.
Evaporative coolers may be installed as an alternative to air conditioning, particularly in climates with very dry air. Evaporative coolers provide mechanical cooling to a building by either direct contact of air with water (direct evaporative cooler) or a combination of a first-stage heat exchanger to pre-cool the air and a second stage with direct air contact with water (indirect/direct evaporative cooler).
The next time you pay your utility bill, try one simple calculation. Divide the total amount by seven. The result is the amount you spend to heat your water. (If you receive separate utility bills for gas and electricity, use the gas bill for this calculation if you have a gas water heater; use the electric bill if you have an electric water heater.) Of course, you may think this cost is a small price to pay for the convenience of a hot shower. But during the course of a year, this cost adds up. And when you consider that 95 million households in this country pay the same percentage, it is easy to see how much money–and energy–is used to heat water.
Several measures can help you decrease water-heating costs in your home. Some specific actions include reducing the amount of hot water used, making your water-heating system more energy efficient, and using off-peak power to heat water.
Generally, four destination points in the home are recognized as end uses for hot water: faucets, showers, dishwashers, and washing machines. Now, you do not have to take cold showers, dine on dirty dishes, or wear dirty clothes to reduce your hot-water consumption. Less radical measures are available that will be virtually unnoticeable once you apply them.
Simply repairing leaks in faucets and showers can save hot water. A leak of one drip per second can cost $1 per month, yet could be repaired in a few minutes for less than that. And some apparently insignificant steps, when practiced routinely at your household, could have significant results. For example, turning the hot-water faucet off while shaving or brushing your teeth, as opposed to letting the water run, can also reduce water-heating costs. Another option is limiting the amount of time you spend in the shower.
Other actions may require a small investment of time and money. Installing low-flow showerheads and faucet aerators can save significant amounts of hot water. Low-flow showerheads can reduce hot-water consumption for bathing by 30%, yet still provide a strong, invigorating spray. Faucet aerators, when applied in commercial and multifamily buildings where water is constantly circulated, can also reduce water-heating energy consumption.
Older showerheads deliver 4 to 5 gallons (15.1 to 18.9 liters) of water per minute. However, the Energy Policy Act of 1992 sets maximum water flow rates at 2.5 gallons (9.5 liters) per minute at a standard residential water pressure of 80 pounds per square inch (552 kilopascals).
A quick test can help you determine if your shower is a good candidate for a showerhead replacement. Turn on the shower to the normal pressure you use, hold a bucket that has been marked in gallon increments under the spray, and time how many seconds it takes to fill the bucket to the 1-gallon (3.8-liter) mark. If it takes less than 20 seconds, you could benefit from a low-flow showerhead. A top-quality, low-flow showerhead will cost $10 to $20 and pay for itself in energy saved within 4 months. Lower quality showerheads may simply restrict water flow, which often results in poor performance.
Because of the different Uses of bathroom and kitchen faucets, you may need to have different water flow rates in each location. For bathroom faucets, aerators that deliver 0.5 to 1 gallon (1.9 to 3.8 liters) of water per minute may be sufficient. Kitchen faucets may require a higher flow rate of 2 to 4 gallons (7.6 to 15.1 liters) per minute if you regularly fill the sink for washing dishes. On the other hand, if you tend to let the water run when washing dishes, the lower flow rate of 0.5 to 1 gallon per minute may be more appropriate. Some aerators come with shut-off valves that allow you to stop the flow of water without affecting the temperature.
A relatively common assumption is that washing dishes by hand saves hot water. However, washing dishes by hand several times a day could be more expensive than operating some automatic dishwashers. If properly used, an efficient dishwasher can consume less energy than washing dishes by hand, particularly when you only operate the dishwasher with full loads.
The biggest cost of operating a dishwasher comes from the energy required to heat the water before it ever makes it to the machine. Heating water for an automatic dishwasher can represent about 80% of the energy required to run this appliance.
Average dishwashers use 8 to 14 gallons (30.3 to 53 liters) of water for a complete wash cycle and require a water temperature of 140 degrees F (60 degrees C) for optimum cleaning. But setting your water heater so high could result in excessive standby heat loss. This type of heat loss occurs because water is constantly heated in the storage tank, even when no hot water is used. Furthermore, a water heater temperature of 120 degrees F (48.9 degrees C) is sufficient for other uses of hot water in the home.
The question, then, is must you give up effective cleaning for hot-water energy savings? The answer is no. A “booster” heater can increase the temperature of the water entering the dishwasher to the 140 degrees F recommended for cleaning. Some dishwashers have built-in boosters that will automatically raise the water temperature, while others require manual selection before the wash cycle begins. A booster heater can add about $30 to the cost of a new dishwasher but should pay for itself in water-heating energy savings in about 1 year if you also lower your water heater temperature. Reducing the water heater temperature is not advisable, however, if your dishwasher does not have a booster heater.
Another feature that reduces hot-water use in dishwashers is the availability of cycle selections. Shorter cycles require less water, thereby reducing the energy cost. The most efficient dishwasher currently on the market can cost half as much to operate as the most inefficient model. If you are planning to purchase a new dishwasher, check the EnergyGuide labels and compare the approximate yearly energy costs among brands. Dishwashers fall into one of two categories: compact capacity or standard capacity. Although compact-capacity dishwashers may appear to be more energy efficient, they hold fewer dishes and may force you to use the appliance more frequently than you would use a standard-capacity model. In this case, your energy costs could be higher than with the standard-capacity dishwasher.
Like dishwashers, much of the cost–up to 90%–of operating washing machines is associated with the energy needed to heat the water. Unlike dishwashers, washing machines do not require a minimum temperature for optimum cleaning. Either cold or warm water can be used for washing most laundry loads; cold water is always sufficient for rinsing. Make sure you follow the cold-water washing instructions for your particular laundry detergent. Washing only full loads is another good rule of thumb for reducing hot-water consumption in clothes washers.
As you would for dishwashers, consult the Energy Guide labels when shopping for a new washing machine. Inefficient washing machines can cost three times as much to operate as efficient machines. Select a machine that allows you to adjust the water temperature and water levels for the size of the load. Also, front-loading machines use less water and, consequently, less energy than top loaders. However, in this country, front loaders are not as widely available as top loaders. Keep in mind that the capacity of front loaders may be smaller than that of most top-loading machines.
Smaller capacity washing machines often have better Energy Guide ratings. However, a reduced capacity might cause you to increase the number of loads you wash and possibly increase your energy costs.
Faucets, showerheads, dishwashers, and washing machines are only destination points for hot water in your home. The journey of your hot water before it reaches these outlets can be fraught with opportunities for energy losses. Fortunately, you can reduce the incidence of water heat loss from the point of departure to the point of arrival by applying a few basic measures.
Reducing hot-water usage is primarily a matter of common sense and exerting a little extra effort to not be wasteful. Once you have applied a few simple, low-cost measures for reducing hot-water consumption, you may want to consider water-heating system improvements if you wish to further reduce your energy bill.
One simple step for reducing water-heating energy costs is lowering the thermostat setting on your water heater. Although some manufacturers set water heaters at 140 degrees F (60 degrees C), 120 degrees F (48.9 degrees C) is satisfactory for most household needs. Furthermore, when heated to 140 degrees F, water can pose a safety hazard (i.e., scalding). For each 10 degrees F (5.6 degrees C) reduction in water temperature, water-heating energy consumption can be reduced 3% to 5%.
If your dishwasher does not have a booster heater, lowering the water-heating temperature is not recommended. Also, many dishwasher detergents are formulated to clean effectively at 140 degrees F and may not perform adequately at lower temperatures. (See previous discussion on Automatic Dishwashers.)
On gas water heaters, thermostats are usually visible. Electric water heaters, on the other hand, may have thermostats positioned behind screw-on plates. As a safety precaution, shut off electric current to the water heater before removing the plates. Keep in mind that electric water heaters may have two thermostats to adjust–one each for the upper and lower heating elements–and adjusting these is tricky. Talk to your local water-heating professional for help with this.
When you plan to be away from home for an extended period of time (at least 3 days), turning the water heater thermostat down to the lowest setting, or even turning the heater off completely, can help you achieve additional savings. Be sure you know how to relight the pilot light on your gas heater, though, before you turn it off.
When you turn on a hot-water faucet during cold weather, it may take several seconds for the water to become hot. This happens because the water travels through pipes from the water heater to the faucet, and some of the pipes may pass through unheated sections of the house, such as the basement. As a result, the hot water loses some of its heat to the surrounding space.
This heat loss can be reduced by insulating hot water pipes wherever they are accessible–especially in unheated areas. Use quality pipe insulation wrap, or neatly tape strips of fiberglass insulation around the pipes. Eventually the water will cool, but it will remain warmer much longer inside insulated pipes.
Insulating your water-heater storage tank is a fairly simple and inexpensive improvement that can help maintain the water temperature at the thermostat setting. Some newer models of water heaters are well insulated and do not need an added layer, but a heater that is warm to the touch needs additional insulation.
Easy-to-install, pre-cut blankets (or jackets) for electric water heaters are widely available and range in cost from $10 to $20. Your local utility company may offer them at a lower price, give you a rebate, or even install them at no cost. When properly installed, a water heater blanket on an electric water heater will pay for itself in energy saved within 1 year. Installation is more difficult on gas- and oil-fired heaters. Ask your local furnace installer for instructions.
If your water heater is at least 7 years old, you should carefully evaluate your water-heating needs and investigate the types of heaters that could replace your current one. Although most water heaters last 10 to 15 years, early investigation and timely replacement can ensure a wiser purchase. For more information on the types of water heaters now available, contact the Energy Efficiency and Renewable Energy Clearinghouse (EREC–see Source List).
Most consumers use more hot water in the evenings and mornings than at other times of the day. For those who have an electric water heater, this usage contributes to the electric utility company’s “peak load,” or the largest amount of power demand that they have to meet on a daily basis. Some utilities are required to offer their customers “time of use” rates that vary according to the demand on their system. Lower rates may be charged at “off-peak” times and higher rates at “on-peak” times. You may be able to lower your electric bills if you can take advantage of these rate schedules. Check with your local electric utility to find out if it offers time-of-use rates for residential customers, and if so, what the rate schedules are. Some utilities even offer incentives for customers who allow their utility to install control devices that shut off electric water heaters during peak demand periods.
Some ways to save on water-heating bills require greater financial investments than others. You may wish to consider the no- or low-cost options before making large purchases. Also allow for circumstances that may be unique to your household when deciding on the appropriate options (e.g., a small-capacity washing machine could meet the needs of a one-person household efficiently).
Although it is not feasible to eliminate water heating in your home, it is possible to substantially reduce water-heating costs without sacrificing comfort and convenience. The tips in this publication can help decrease your costs for heating water.
Note: Installation is more difficult on gas- and oil-fired heaters. Ask your local furnace installer for instructions.
Cut the tank top insulation to fit around the piping in the top of the tank. Tape the cut section closed after the top has been installed.
Fold the corners of the tank top insulation down and tape to the sides of the tank (Figure 1).
Position the insulating blanket around the circumference of the tank. For ease of installation, position the blanket so that the ends do not come together over the access panels in the side of the tank. Some tanks have only one access panel.
Secure the blanket in place with the belts provided. Position the belts so they do not go over the access panels (Figure 2). Belts should fit snugly over the blanket but not compress it more than 15% to 20% of its thickness. The installation is easier with two people. If working alone, use tape to hold the blanket to the top until you get the belts into position.
If your water heater has the temperature/pressure relief valve and the overflow pipe on the side of the tank instead of on the top, install the blanket so these items are outside of the blanket. Depending on the piping arrangement and location, you may need to compress, or even cut, the blanket.
Locate the four corners of the access panel(s). Make an x-shaped cut in the insulating blanket from corner to corner of each access panel (Figure 3).
Fold the triangular flaps produced by the cuts underneath the insulating blanket (Figure 4). Repeat steps 6 and 7 for the rating/instruction plate.
The blanket must not be installed on a leaking tank.
The following organizations and publications provide more information on hot-water energy efficiency. Much of the information included in this publication was obtained from several of these sources. This list does not cover all the available books, reports, and articles on hot-water energy efficiency, nor is the mention of any publication to be considered a recommendation or endorsement. To obtain the publications in this list, contact your local library or bookstore or the publisher. Check publication prices through your bookstore or the publisher before placing an order.
Further information about efficient water heating can be obtained by contacting:
The Energy Efficiency and Renewable Energy Clearinghouse (EREC) P.O. Box 3048 Merrifield, VA 22116 (800) 363-3732
Books and Reports Consumer Reports 1992 Buying Guide Issue, Consumers Union of the United States, Inc., 101 Truman Avenue, Yonkers, NY 10703-1057, December 1991.
“An Investigation of Off-Peak Domestic Hot Water Heating,” ASHRAE Journal, p. 32, January 1990.
This document was produced for the U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory (NREL), a DOE national laboratory. The document was produced by the Information Services Program, under the DOE Office of Energy Efficiency and Renewable Energy. The Energy Efficiency and Renewable Energy Clearinghouse (EREC) is operated by NCI Information Systems, Inc., for NREL/DOE. The statements contained herein are based on information known to EREC and NREL at the time of printing. No recommendation or endorsement of any product or service is implied if mentioned by EREC.
DOE/GO-10095-063 FS 204 January 1995