Knowing the ins and outs of your home furnace can help you save energy and money, increase your system’s efficiency and provide better comfort for you and your family this fall and winter. Use the features below to learn the basics about this equipment in your home, and take control of your energy usage this heating season.

Watch the video

Learn what’s under your furnace cover and get tips on how to take control of your energy usage.

Learn how your furnace works

Hover over the different parts of the furnace for a brief description of how they work.

Blower Fan

Motor-driven fan that powers the air to pass through the furnace. The fan draws air from your living spaces through the return air vent and blows it across the heat exchanger causing it to get hot, and eventually blows the warmed air out the supply duct to heat the home.


Filters air particles/debris before air gets heated. The filter increases the efficiency and life of your furnace by protecting it from dust and particles.

Return Air

Duct that carries room temperature (unheated) air into the furnace to be heated.

Heat Exchanger

Hot combustion gases produced by the burners circulate inside of the metal heat exchanger causing it to get hot. The air current is heated as it is blown across the hot metal surface of the heat exchanger.

Natural Gas Line

Supplies natural gas to the burners in the heat exchanger.


A duct/pipe where your exhaust (combusted) gases exit your home to the outdoors.


Where a mixture of air and fuel is burned to produce heat.

Heated Air

Supply ducts carry warm air into the occupied space where it flows out of floor, wall, or ceiling vents throughout your home.

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Earn up to $400 in rebates for installing high efficiency equipment, start by finding a contractor.