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What is an Air Furnace?

Amy Hunter
Amy Hunter

An air furnace works by heating the air in the home. It is an efficient and effective way to heat. To use an air furnace as a heating system,the home must have ductwork. If your home does not have ductwork, the cost of adding it to your home should be considered when budgeting for an air furnace system.

An air furnace is a simple structure. Ductwork runs through the house, with heating registers in each room. There will also be air returns, usually one on each room of the home. Room air is pulled into the ductwork through the air returns. It travels through the ductwork to the furnace.

A propane tank can hold fuel for a furnace.
A propane tank can hold fuel for a furnace.

Once inside the furnace, the air enters a metal box. This box contains some type of heating source. If the air furnace is powered by electricity it will have a heating element. Other fuel sources use a pilot light and burner system. The level of heat in the furnace box is determined by a thermostat.

Inside the furnace box, the room air is heated. It then travels out of the box, through the ductwork. It enters each room through the heat registers. The heating system works in a continual circle, pulling air into the furnace from the room registers, heating the air and then sending it back into the room.

The most common types of fuels used by air furnaces are natural gas and electricity. If you are considering adding an air furnace to your home, you must decide what type of fuel you will use before purchasing your furnace. The decision will be based on what types of fuel are available in your area and the cost of each.

Electricity is typically the most expensive form of power for warming a home. Natural gas, propane and heating oil are normally more affordable choices. These choices are not available everywhere however, and some people prefer electricity because it provides a stable, nonflammable and reliable fuel source.

If you are not sure what type of fuel would be best for your heating system, take the time to talk with your local utilities. Each utility should provide you with the estimated cost per day of running a furnace with their fuel source. They can also let you know the benefits and drawbacks of the fuel that they provide. Before making the substantial investment in a new air furnace, it is important to choose the fuel system that will make you happy. You can expect a new air furnace to last at least 12 years, and as long as two decades, so investing the time before you make a purchase is important.

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    • A propane tank can hold fuel for a furnace.
      By: Ty Konzak
      A propane tank can hold fuel for a furnace.