Heating and Cooling for Your HomeHeating and cooling your home accounts for about 44 percent of your utility bill. It uses more energy than any other system in your home. Reducing energy use for heating is the one best way to reduce your home's contribution to global environmental problems. Because residential energy use represents 20 percent of all U.S. energy use, and nearly half of all energy used in the home is for heating and cooling, a primary focus of the ENERGY STAR® Labeling Program is home heating and cooling equipment. Consumers spend 6 to 12 percent of their gross incomes paying for home fuel and utility costs. By purchasing energy-efficient heating and cooling equipment, consumers can reduce energy use, save money, and help the environment. Heating and cooling equipment comes with two price tags: the cost of purchasing the equipment and the cost to run it. Although ENERGY STAR® heating and cooling systems often cost more to buy, they can cost much less to run because they use less energy. The Environmental Protection Agency (EPA) estimates that when properly sized, installed, and maintained, ENERGY STAR labeled heating and cooling products can save consumers 10 to 40 percent on heating and cooling costs.
ENERGY STAR® guidelines
AFUE (Annual Fuel Utilization Efficiency), SEER (Seasonal Energy Efficiency Ratio), HSPF (Heating Seasonal Performance Factor), COP (Coefficient of Performance), and EER (Energy Efficiency Ratio) measure heating and cooling efficiency. In all cases, the higher the number, the more efficient the product is (for example, a 13 SEER air conditioner is more efficient than a 12 SEER air conditioner). EnergyGuide labels are on all new room air conditioners, central air conditioners, heat pumps, and furnaces. These labels are bright yellow with black lettering. The labels for room air conditioners, central air conditioners, heat pumps, and furnaces provide the range of energy efficiency ratings for these products (EER, SEER, HSPF & SEER, and AFUE, respectively). Labels on the most efficient models will show "This Model's Efficiency" at or near the right-hand end of the range, close to the words "Most Efficient." New furnaces now carry EnergyGuide labels showing their Annual Fuel Utilization Efficiency (AFUE). EnergyGuide labels on heating and cooling equipment refer customers to manufacturers' fact sheets available from the seller or installer. These fact sheets give further information about the efficiency and operating costs of the equipment under consideration. Remember, even with an energy efficient system within your home you will have a much greater impact on your energy costs if you take a whole-house approach. By combining proper equipment maintenance and upgrades with appropriate insulation, weatherization, and thermostat settings, you can cut your energy bills and your pollution output in half.ENERGY SAVING TIPS WHEN HEATING AND COOLING THE HOME•Set your thermostat as low as is comfortable in the winter and as high as is comfortable in the summer. •Clean warm-air registers and baseboard heaters as needed; make sure they're not blocked by furniture, carpeting, or drapes. •Use kitchen, bath, and other ventilating fans wisely; in just 1 hour, these fans can pull out a houseful of warmed or cooled air. Turn fans off as soon as they have done the job. •During the heating season, keep the draperies and shades on your south-facing windows open during the day to let sunlight enter your home and closed at night to reduce the chill you may feel from cold windows. •During the cooling season, keep the window coverings closed during the day to prevent solar gain. •Do not turn the heat off in unoccupied rooms if it adversely affects the rest of your system. For example, if you heat your house with a heat pump, closing the vents could harm the heat pump. •Use a programmable thermostat to control your temperature settings. •Clean and replace filters once a month. •Check ducts for air leaks. •Don't set your thermostat at a colder setting than normal when you turn on your air conditioner. It will not cool your home any faster and could result in excessive cooling and, therefore, unnecessary expense. •Don't place lamps or TV sets near your air conditioning thermostat. The thermostat senses heat from these appliances, which can cause the air conditioner to run longer than necessary. •Set your thermostat on 78° F or higher. Each degree setting below 78° F will increase energy consumption by approximately 8 percent. The less difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be. •Do not use a dehumidifier at the same time your air conditioner is operating because it will increase the cooling load and force the air conditioner to work harder. •Delay heat-generating activities such as dishwashing and food preparation until evening on hot days. DuctsThe delivery system is often an overlooked element in a home's heating, ventilation, and air-conditioning (HVAC) installation. Regardless of the efficiency ratings of heating and cooling systems, they all rely on properly designed, installed, and insulated ducts to deliver the heated and cooled air. Proper duct sealing and insulation affect a house's comfort and energy use significantly. Poorly designed ducts and poor duct work can cause uneven air distribution, poor house ventilation, and problems with humidity levels. The resulting conditions are areas that are too cold or too hot, an increase in dust and other contaminants being circulated, and growth of mold and mildew. Sealing MaterialsRoutinely, instances have been found where sections of ducts were never installed, connected, or had broken or fallen away completely, leaving gaps in the system. Using duct tape to seal duct joints and seams has been prohibited in a number of building codes because it will peel and crack when exposed to humidity and temperature changes. The term "mastic" is commonly used to describe a number of sealing systems, including some types of adhesive tapes. Mastic is a gooey paste recommended for sealing duct gaps and seams. InsulationIn a typical home, many supply and return ducts are routed through unconditioned spaces such as the attic, basement/crawlspace, or garage. Because of the temperature extremes in these spaces, even a perfectly sealed duct system will lose energy across the duct surface. Studies have found that uninsulated ducts can lose about the same amount of energy through conduction as they do through leaks. To reduce this energy loss, route ducts through conditioned spaces where possible, and insulate them well in unconditioned spaces. You can insulate by simply wrapping insulation (usually fiberglass insulating sheets) around installed, secured, and sealed duct systems, or by using flexible, pre-insulated ducts. Sealed and insulated metal ducts tend to perform better and last much longer than flexible insulated ducts. Poorly suspended ducts, especially flexible ducts, can sag over time, restricting airflow through the system. Also, the corrugated inner surface of flexible ducts resists airflow. Duct Testing MethodsIt is a good idea to test a home to make sure it has an adequate duct network and that sealing methods are working as they should. A typical forced-air distribution system's duct network delivers conditioned air from the furnace, heat pump, or air-conditioner to the registers in the living spaces, and air from these areas back to the appliance to be heated or cooled. Several organizations have developed testing methods to determine residential duct tightness, and several utilities have started test programs. Homeowners should not test and repair ducts themselves, but hire qualified experts. Heating SystemsHeat PumpsA heat pump can save as much as 30 to 40 percent of the electricity you use for heating. Gas heat pumps as well as electric heat pumps are available for home use. Heat pumps are the most efficient form of heating in climates such as Mississippi's. They provide up to four times more heating than the same amount of energy used. High efficiency heat pumps dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer. Ground source or thermal heat pumps are more efficient and economical to operate when compared to conventional air source heat pumps. Heat pumps are rated for heating and cooling in terms of capacity and efficiency. Capacity ratings are generally in British thermal units per hour. Heating efficiency for air source heat pumps is indicated by the Heating Season Performance Factor (HSPF). Heat pump efficiency depends on outdoor temperature. The performance of an air source heat pump in heating mode decreases with the drop in outside temperature. During the cooling period the heat pump operates as a central air conditioner. The Seasonal Energy Efficiency Rating (SEER) tells you the seasonal cooling performance. Federal efficiency standards require conventional heat pumps to have an HSPF rating of at least 6.8 and a SEER rating of at least 10.0. The most efficient air source heat pumps have an HSPF rating between 7.7 and 10.0.HEAT PUMP ENERGY SAVING TIPS WHEN BUYING AND USING•Heat pumps must be sized and installed properly to work efficiently. They are sized either based on heating demand or cooling demand, depending on which is larger. •Ground source heat pumps (GSHPs) are more efficient and less noisy than conventional heat pumps. They may be more expensive to install, but the dramatic improvement in efficiency yields life cycle cost savings. Installation will depend on the size of your lot, the subsoil, and the landscape. •Select a heat pump with a higher HSPF. If the units you are comparing have similar HSPF ratings, check their steady-state rating at -8.3 degrees C. The unit with the higher rating will be more efficient. •Select a heat pump with a demand-defrost control. This will minimize the defrost cycles and reduce supplementary and heat pump use. •Select a unit with an outdoor sound rating of 7.6 decibels or lower. The lower the value, the less noise. •Ductwork must be large enough to handle air flow at 50 to 60 liters per second per kilowatt-hour or 400 to 500 cubic feet per minute per ton of cooling capacity. •Place the outdoor unit away from windows and adjacent buildings. You can mount units on noise-absorbing materials to reduce vibration and noise. •Do not manually set back the heat pump's thermostat if it causes the electric resistance heating to come on. Electric resistance heating is more expensive. •Continuous indoor fan operation can degrade heat pump performance unless you use a high-efficiency, variable speed fan motor. •Operate the system on the "auto" fan setting on the thermostat. •Maintain the system according to the manufacturer's instructions. •Dirty filters, coils, and fans reduce airflow and can impact system performance and service life. Compressor damage can result if it continues for an extended time. •Clean and lubricate the fan motor annually to ensure airflow for proper operation. Incorrect pulley settings, loose fan belts, or incorrect motor speeds can all contribute to poor performance. •Outdoor units should be protected from high winds because of defrost problems. Central FurnaceA central furnace is measured for Annual Fuel Utilization Efficiency (AFUE). AFUE is a measure of how efficient the unit is in using fossil fuel (gas) or electricity over a period of a year. The AFUE rating can be as high as 97percent, converting nearly all the fuel to useful heat for the home. Be sure to specify high efficiency heating systems for new construction. FireplacesThe fireplace is the most inefficient heat source you can possibly use. It literally sends your energy dollars right up the chimney along with volumes of warm air. A roaring fire can send out as much as 24,000 cubic feet of air per hour to the outside, which must be replaced by cold air coming into the house from the outside. Your heating system must warm up this air, which is then exhausted through your chimney. ENERGY TIPS FOR USING A FIREPLACE•If you never use your fireplace, plug and seal the chimney flue. •Keep your fireplace damper closed unless a fire is going. Keeping the damper open is like keeping a 48-inch window wide open during the winter; it allows warm air to go right up the chimney. •When you use the fireplace, reduce heat loss by opening dampers in the bottom of the firebox (if provided) or open the nearest window approximately 1 inch, and close doors leading into the room. Lower the thermostat setting to between 50°F and 55°F. •Install tempered glass doors and a heat-air exchange system that blows warmed air back into the room. •Check the seal on the flue damper and make it as snug as possible. •Add caulking around the fireplace hearth. •Use grates made of C-shaped metal tubes to draw cool room air into the fireplace and circulate warm air back into the room. HEATING SYSTEMS ENERGY SAVING TIPS WHEN BUYING AND USING•When specifying the size of the heating system, first make every effort to have the greatest energy efficiency of the house, then run a heat-loss calculation. •Select a system with a good warranty and a reputable company to back it up. •When purchasing a gas-fired system, specify sealed combustion. Sealed combustion appliances bring outside air directly into the burner and exhaust flue gases (combustion products) directly to the outside, without the need for a draft hood or damper. They generally burn more efficiently and pose no risk of introducing dangerous combustion gases into your house. With nonsealed-combustion appliances, back-drafting of combustion gases can be a big problem. •Contract for professional cleaning and tuning every other year for a gas-fired unit. •Select energy-efficient equipment when you buy new heating equipment. Your contractor should be able to give you energy fact sheets for different types, models, and designs to help you compare energy usage. Look for high Annual Fuel Utilization Efficiency (AFUE) ratings and the Seasonal Energy Efficiency Ratio (SEER). The national minimums are 78 percent AFUE and 10 SEER. Cooling SystemsCentral Air ConditionersHigh efficiency cooling equipment can lower utility bills, improve comfort and air quality throughout the home, and help reduce air pollution. Central air conditioners use energy to pump heat out of buildings, distribute cool air within buildings, and remove moisture from buildings. Central air conditioners are rated according to their seasonal energy efficiency ratio (SEER). SEER indicates the relative amount of energy needed to provide a specific cooling output. The average SEER for units sold today is between 10.0 and 11.0. The minimum SEER allowed by the Federal Government is 10.0 for a split system and 9.7 for a single-package system. Select a central air conditioner with a SEER of 12 or greater. Also specify that the air conditioner be approved for the ENERGY STAR® label. Central units are more efficient than window units. The central system may be able to use duct work in a forced air heating system. You would decide this depending on the size of the air conditioning unit and the relative heating and cooling loads.CENTRAL AIR CONDITIONING ENERGY SAVING TIPS WHEN BUYING AND USING•When shopping for a central air conditioner, look for a SEER rating of 12 or higher. •Proper sizing and installation are the key to determining air conditioner efficiency. Too large a unit will not adequately remove humidity. Too small a unit will not be able to attain a comfortable temperature on the hottest of days. Improper unit location, lack of insulation, and improper duct installation can greatly diminish efficiency. •When selecting a unit, look for a system with a fan-only switch so you can use the unit for nighttime ventilation, a filter check light to remind you to check the filter, and an automatic-delay fan switch to turn off the fan for a few minutes after the compressor turns off. •If possible, place the outdoor unit on the north or east side of the home in a shaded spot. Plant trees or shrubs to shade air conditioning units but not to block the airflow. A unit operating in the shade uses as much as 10 percent less electricity than the same one operating in the sun. •Effectively shade east and west windows. •Check the refrigerant charge level. Overcharging or undercharging the system will affect the proper operation of the unit. •Dirt build-up on the indoor coil is the single most common cause of poor efficiency. SourcesSources EREC Fact Sheet: Automatic
and Programmable Thermostats, U.S. Department of Energy Copyright by Mississippi
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