How Do Furnaces Actually Work?

January 12, 2022
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As winter approaches, your furnace will do the important work of heating your home. It’s one of the most significant appliances you have because it keeps you and your family both safe and comfortable. Most people take this device for granted, but perhaps you’ve wondered how yours works. Let’s take a look.

Heat Exchanger

The heat exchanger is the heart of a gas furnace. It absorbs the heat from the burner and passes it on to the cool air above it that is drawn in from your home. The heat exchanger also keeps combustion gasses from being blown into your indoor air. If it becomes cracked or damaged, it’s likely that your entire furnace will need to be replaced.

Should your heat exchanger in Richmond, TX, become damaged, our technicians at Air Express Air Conditioning & Heating can help you decide whether your furnace requires repair or replacement. We’ve been assisting families throughout the Greater Houston area for over 15 years.

Combustion Chamber

It’s in the combustion chamber of a furnace that gas is consumed. Gas is mixed with air and ignited by burners. There’s a flame sensor that ensures the gas is getting ignited; otherwise, it would leak out of the furnace, posing a safety hazard.

Ignition Source

When your home needs heat, there’s a regulator that opens so gas is fed into the combustion chamber. Often called the glow stick, the source of heat in modern furnaces is a silicon nitride ignition.


The plenum is where cold air from your home is heated and then blown into the ductwork. When warm air is blown into your home, cold air is forced into a return register and brought back into the furnace.

Where the plenum is located in the furnace depends on the manufacturer. However, it’s always placed near the heat exchanger. Its location allows it to heat the air moving through it so your home is warmed.

Our team at Air Express Air Conditioning & Heating installs, repairs and maintains heaters and air conditioners. Our other services include indoor air quality, duct sealing and home performance enhancements. Whether you need a heating or cooling solution, please give us a call today.

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