Home > >

Furnaces 101

How Gas Furnaces Work

By Dale V.  |  Power Equipment Expert

Do you wish you had a better grasp on things when the heat goes out and your family is shivering under the blankets? By understanding how your furnace works, you'll know how to keep it running and, if needed, how to replace it.

First, spend a few seconds looking at the diagram below and see how the furnace is connected to ductwork that wraps throughout the house (ignore the air conditioner for now). The air ducts are like the arteries and veins of your home. Instead of blood, they distribute air to and from the heart of the system: the furnace.

When finished, scroll down to learn step-by-step how your furnace works.

 


Image: Goodman Manufacturing

 

View Our Best Furnaces

 

Basic Heating Cycle
A forced-air furnace heats your home through a heating cycle that looks like this:

  1. Natural gas or propane is ignited in the furnace's burner.
  2. The burner flames heat up a metal heat exchanger, while the exhaust flows out the flue.
  3. The heat exchanger warms incoming cold air.
  4. The furnace's blower forces the heated air into the ductwork and distributes it throughout the home.
  5. As the warm air fills each room, the colder, denser air is drawn back into the furnace via the return ducts, repeating the process.

Gas Furnace Components
There are many components that work together in a furnace to help keep you comfortable. With so many types of models on the market, it can be tough to know what they are and their functions.

Here are some of the main gas furnace components to know.

Beyond Basic Functions
Now that you know how basic furnace components work together to keep you comfortable, it will be easier for you to make a selection about which features are important when picking the perfect furnace.

Next, we'll take a deeper look at those features and key considerations you should make for your next furnace.

 

Next: Furnace Buying Guide
 

 

Learn About Other Central Forced Air Systems

HVAC-101 | Gas Furnaces-101 | Heat Pumps-101 | Packaged Units-101 | Air Conditioning-101 | Air Handlers-101