By Jim Crawford, University Extension
With the first cold evenings signaling winter is approaching, I have received several inquiries about space heaters. It can be expensive to heat a home so many people are looking for ways to save a few dollars on their heating costs. One method is to turn down the thermostat and use space heaters to warm the room they are occupying.
There are two general classes of space heaters: fuel-burning (kerosene or gas-fired) and electric. Electric space heaters are a popular choice, in part because electricity costs are not predicted to fluctuate as quickly as other fuels. They also do not require the user to purchase or store flammable fuels.
There are several types of electric space heaters. Convection heaters produce warm air. Some convection heaters have a metal element that glows red – like the element on your stove and can be a burn or fire hazard. Other convection heaters may look like a radiator and are filled with oil. These operate at low temperatures and do not get hot enough to cause burns or fire.
The other type of electric space heater, a radiant heater, mainly warms nearby objects. Radiant heaters have a quartz tube that gets hot and mainly produces infrared energy. This infrared energy heats walls, chairs, tables, and you which in turn heats the air.
With the many types of electric space heaters available, one important reality that buyers should be aware of is heater efficiency. The process of converting electricity into heat is 100% efficient. This is true for both expensive and inexpensive heaters and is based on laws of physics. While there are advantages and disadvantages to various types of heaters, you should not be misled by claims of spectacular performance. An electric space heater operating at 1500 Watts will produce exactly 5119 BTU’s (a measure of heat) each hour. Period.
The questions I most often hear are:
“Can this unit reduce my energy bill by half?” The short answer is probably not. A space heater does just that - it heats a space. If you stay in one room 90% of the time and use a space heater to supplement the heat in that room while you turn down the heat to the rest of the house, you may save some energy. An average, 1500-watt electric space heater produces 5119 BTUs per hour. The average home furnace produces about 100,000 BTUs per hour. To save 50% on your heating costs by using a space heater you would have to drastically turn down your primary heat source. You need to be careful how much you turn down the heat to the rest of the home as the result can be frozen pipes or excessive condensation forming on walls and ceilings.
“Can this model space heater produce more heat than other space heaters?” The answer is only if it uses more electricity. All electric space heaters, regardless of cost, operate at 100% efficiency. Therefore, heaters with similar wattage ratings will produce the same amount of heat.
“I saw an advertisement for a space heater using space age technology that will be more efficient and use less electricity.” How much more efficient can you get than 100%?? No matter what material you are using, you will get 3412 BTUs for every kilowatt hour of electricity used. If the heater contains a special oil or metal to hold the heat, the resulting heat will be released more slowly over a longer period of time than a heater with an exposed element. This slower discharge rate may enhance your comfort but you cannot get more heat energy out of a device than the amount of electricity put into it unless the device catches fire. This same medium that holds and releases the heat slowly also means that it will take longer to produce heat when first turned on.
Regardless of the model, it is extremely important to follow manufacturer’s instructions for operation. Since electric space heaters consume a lot of energy, they should be used only on electrical circuits that do not have other major appliances (refrigerators, microwaves, etc.) connected to them. If you regularly blow a fuse, or the circuit breaker trips when you use your space heater, try using another outlet. Most of the electric circuits supplying wall outlets in your home are rated at 1800 or 2400 watts. Therefore, an electric space heater operating at 1500 watts is using more than half the rated capacity of its circuit. Due to the large amount of current they pull, you should always try to avoid using an extension cord with a space heater. If you must use an extension cord, make sure it is rated for that size of load. NEVER use a light duty lamp cord or put an extension cord under a rug as these will pose a fire hazard.
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