|
||||||||
Heating | ||||||||
For Your Home | ||||||||
Electric Heating | ||||||||
Electric Resistance Heat Electric Baseboard Heaters Electric Wall Heaters Electric Radiant Heat Electric Space Heaters Electric Furnaces Electric Thermal Storage Energy-Saving Measures Thermostats for Electric Heating Electricity is a versatile but precious energy source. Because it is needed for refined power equipment such as computers and medical machinery, when it is used for less-refined needs such as heating it should be used as efficiently as possible. If you use electricity for heating your home, the following will help you save money and minimize your energy consumption when using electrical heating systems.
Electric resistance heat can be supplied by centralized forced-air furnaces or by zonal heaters in each room, both of which can be composed of a variety of heater types. Zonal heaters distribute electric resistance heat more efficiently than electric furnaces because you set room temperatures according to occupancy. In addition, zonal heaters have no ducts that can lose heat before it reaches the room. However, electric furnaces can accommodate central cooling easier than zonal electric heating, because the air conditioner can share the furnace's ducts. Electric resistance heat can be provided by electric baseboard heaters, electric wall heaters, electric radiant heat, electric space heaters, electric furnaces, or electric thermal storage systems. Electric Baseboard Heaters Baseboard heaters are usually installed underneath windows. There, the heater's rising warm air counteracts falling cool air from the cold window glass. Baseboard heaters are seldom located on interior walls because standard heating practice is to supply heat at the home's perimeter where the greatest heat loss occurs. Baseboard heaters should sit at least three-quarters of an inch (1.9 centimeters) above the floor or carpet. This is to allow the cooler air on the floor to flow under and through the radiator fins so it can be heated. The heater should also fit tightly to the wall to prevent the warm air from convecting behind it and streaking the wall with dust particles. The quality of baseboard heaters varies considerably. Cheaper models can be noisy and often give poor temperature control. Look for labels from Underwriter's Laboratories (UL) and the National Electrical Manufacturer's Association (NEMA). Compare warranties of the different models you are considering. Electric Wall Heaters Electric Radiant Heat There are several types of electric radiant heaters. The most common are electric heating cables imbedded in floors or ceilings. Other radiant heating systems use special gypsum ceiling panels equipped with factory-imbedded heating cables. Newer ceiling-mounted radiant panels made of metal provide radiant heat faster than other types because they contain less material to warm up. Radiant heat offers draft-free heating that is easily zoned. Unlike other heating systems, it occupies no interior space. This allows you complete freedom to place furniture without worrying about impeding air flow from floor registers or baseboard heaters. Manufacturers claim that radiant heat can provide comfort similar to other systems at lower indoor air temperatures, saving around 5% of space heating costs. Critics of radiant heat say that it can be difficult to control air temperature with a thermostat. The large heat-storage capacity of the concrete or plaster surrounding the heating cables may result in greater-than-normal fluctuations in the room air temperature, since it takes quite a while to heat up the storage mass. Also, some occupants complain about their heads being too warm in rooms that utilize ceiling radiant heat. Supplying heat at the ceiling or floor, which are locations that typically border the outdoors or unheated spaces, can result in greater heat losses. For example, if there are any flaws in a heated concrete slab or gaps in the ceiling insulation above heating elements, a significant percent of the electric heat may escape to the outdoors without ever heating the home. Electric Space Heaters Portable space heaters, as well as many built-in space heaters for small rooms, have built-in thermostats. Larger rooms heated with built-in electric space heaters should have low-voltage thermostats installed in an area that maintains the room's average temperature. Portable electric space heaters can pose a significant safety hazard unless they have safety features and are used properly. Many cheaper or older portable electric space heaters are not safe for most home uses. Their red-hot elements and lack of safety features can lead to fires. When buying a portable electric space heater, select one with all of these safety features:
To use your portable electric space heater safely, follow these guidelines.
Electric Furnaces Blowers (large fans) in electric furnaces move air over a group of three to seven electric resistance coils, called elements, which are each rated at five kilowatts. The furnace's heating elements activate in stages to avoid overloading the home's electrical system. Overheating is prevented by a built-in thermostat called a limit controller. This limit controller may shut the furnace off if the blower fails or if a dirty filter is blocking air flow. Electric Thermal Storage Some storage systems attempt to use the ground underneath homes for thermal storage of heat from electric resistance cables. However, this requires painstaking installation of insulation underneath concrete slabs and all around the heating elements to minimize major heat losses to the earth. Ground storage also makes it difficult for thermostats to control indoor temperatures. Energy-Saving Measures Insulation However, just because you have an adequate R-value does not necessarily mean your home is well insulated. The insulation must be properly installed as well. Gaps and voids in the insulation—even small ones—create air convection or air leakage that markedly reduce rated R-values. Windows While energy-efficient windows are important in any house, electrically heated homes especially should have windows with U-values of less than 0.40. Advanced window designs incorporate multiple glazing layers, heat-reflective coatings, or gas fillings to reach U-values less than 0.25. Installing storm windows—even over double-pane windows—is often cost effective for homes in cold climates with high electricity costs. Reducing Air Leakage: Your Home's Envelope Your Home's Duct Work Leaking ductwork can create positive and negative room pressures that often increase air leakage through floors, exterior walls, and ceilings. Reducing or eliminating air leaks will make your home more energy efficient and comfortable. The importance of airtight ducts has only recently been recognized by the building industry. New ducts need to be sealed with commercial duct mastic as they are assembled. Existing duct systems can be leak-tested and sealed by an experienced professional. Zone Heating Zone heating can produce energy savings of more than 20% compared to heating both occupied and unoccupied areas of your house. Of course, the amount of savings you will achieve depends on how the portable or built-in zone heaters are combined with your centralized heating system. One recommended zone heating strategy involves controlling the centralized heating system with an automatic setback thermostat. During the times when everyone is at home and active, the automatic setback thermostat provides a comfortable temperature throughout the house. For the remainder of the day or night, it lowers house temperatures to between 50°F and 60°F (between 10°C and 15.6°C). During these setback times, zone heaters provide additional room heat only as needed. Furnace Filters Filters are composed of either fiberglass wool framed in cardboard, air-permeable foam rubber, or fibrous plastic. They are usually positioned near the blower. Depending on the type of filter used in your system, it is a good idea to replace or clean them monthly during the heating season. Read your furnace's instruction manual for more information. Indoor Air Quality and Ventilation Zone-heated homes with fairly airtight building shells can have moisture and air pollution problems because of very low air leakage along with the lack of a ventilation system. Mechanical ventilation can remove air pollution and moisture. A relatively airtight, electrically heated home should be supplied with fresh air from a controlled mechanical ventilation system. This ventilation system can consist of exhaust fans, a central exhaust air system, an air-to-air heat exchanger with its own ducts, or an outdoor-air inlet into an electric furnace or heat pump. Thermostats for Electric Heating Line-Voltage Thermostats Low-Voltage Thermostats Low-voltage thermostats are always installed in remote locations, rather than being integrated into the heater. They control temperature more precisely than line-voltage thermostats. Low-voltage thermostats are preferred for larger rooms, heated by radiant panels or electric baseboard heaters, because they produce better comfort. Automatic Setback Thermostats Automatic setback thermostats can be used to control all types of electric heat. For baseboard and radiant heat, line voltage setback thermostats are available. These are either programmed with a clock or they require the user to push a button at regular intervals to avoid the setback temperature (usually 10 or 15 degrees). Source: U.S. DOE, Energy Efficiency and Renewable Energy Network, Consumer Energy Information: EREC Reference Brief. EREC is operated by NCI Information Systems, Inc. for the National Renewable Energy Laboratory/U.S. Department of Energy. The content of this brief is based on information known to EREC at the time of preparation. No recommendation or endorsement of any non-U.S. Government product or service is implied if mentioned by EREC. | ||||||||
| ||||||||
|