Does a Gas Furnace Use Electricity?

Like many of our homeowners in Alexandria VA, you are probably concerned with the rising cost of energy. The typical homeowner spends more on heating and cooling than any other utility cost. If you live in a warm climate like that of Alexandria VA, then your biggest cost will be for cooling. The compressor will draw the biggest load, but this will only be a factor when in cooling mode, unless you own a heat pump.

Furnace Igniter

The question is, “does a gas furnace use electricity?”  If you are using a gas furnace for heating, then the only electrical cost will be what is required to operate the fan motor and the igniter. The igniter lights the flame and only fires for a brief time; this is the clicking sound that you can hear if you are very near the furnace at startup. The electrical usage for ignition is negligible. An older model with a glow type igniter will use more energy, but these are not very common any more. If you do have a gas furnace that uses one of these, then you will be able to have an even greater impact on savings by purchasing a replacement.

Furnace Fan Motor

The only other electrical requirement of a furnace is the load required to run the fan. Fan technology has advanced steadily in the last few years. The biggest single factor affecting the energy use of fans has been the development of the variable-speed fan motor. Older systems used a single-speed motor that had one speed: wide open. Even ceiling fans are more technologically advanced than that! As the name implies, a gas furnace with a variable-speed motor has the capacity to operate at various levels of output. When conditions are moderate, then you obviously need less cooling or heating. An older gas furnace cannot alter the output to a lower level, so the unit will continue to operate at maximum capacity, using a maximum amount of energy. Conversely, a variable-speed fan will ramp down in capacity when needed, saving energy in the process.

Variable Speed Furnace Fans

The difference in energy required between single-speed and variable-speed models is significant. A standard fan motor will typically use about 400 watts per hour while a variable-speed model will only use 75 watts per hour. This is the most direct way that the variable-speed units save electricity, but there are other means by which they affect energy usage as well. The most significant of these is by keeping a more constant temperature in your home. Because the fans can lower to 50 percent of output or less when they operate at low speed, it means that the airflow is both colder and more consistent. The temperatures will likewise remain more constant, reducing the need for off and on operation. Stop and go fan usage, just like city driving in your car, is the least efficient mode in terms of energy load requirements. Avoiding this will allow your gas furnace in Alexandria VA to save energy and money.

At Brennan’s Heating and Air Conditioning, we are here to answer your questions and concerns regarding all aspects of heating and cooling, please give us a call.