Many people have gas furnaces that keep their homes warm throughout the winter. By understanding how this important part of the home works, you’ll know when it needs repair or replacement.

Heating Cycle

The heating cycle begins when your thermostat tells the furnace to turn on. Natural gas is ignited in the burner. There’s a flame sensor that turns off the gas if it doesn’t detect that the burner is on. Once your home is at your desired temperature, the thermostat will tell the furnace to turn off.

Heat Exchanger

Your furnace has a heat exchanger that is warmed by the combustion of natural gas in the burner. Heat exchangers have looped tubes that transfer heat to the air passing through them. A high-efficiency gas furnace has a second heat exchanger to extract even more heat.

The heat exchanger is a very important part. It prevents combustion gasses from entering your home. If it cracks, you most likely need a new furnace.

The team at Batey Brothers Heating & Cooling in Scottsboro, AL, can help you decide whether your gas furnace requires repair or replacement. Our NATE-certified technicians can service all makes and models of furnaces.

Blower Motor and Fan

The blower motor and fan move heat through your furnace’s plenum. It is blown into the ductwork of your home. When the blower and fan are running, warm air comes out of registers in the rooms of your home.


When natural gas is combusted, it produces dangerous gases. One of these is carbon monoxide, which is deadly in high concentrations. These gases exit your home through a flue above the furnace.

Return Air

As warm air fills the rooms of your home, colder air is drawn back toward the furnace through return ducts. The air is then warmed and blown back into your home.

Batey Brothers Heating & Cooling replaces, repairs, and tunes-up gas furnaces, heat pumps, geothermal systems, air conditioners, and packaged systems. We can also help you with thermostats, fan coils, and evaporator coils. Call today to find out more.

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