A gas furnace has become one of the most common heating appliances that distributes heat. Furnaces do this by burning fuel internally to warm air, water or steam. The most common type of furnace is a forced-air furnace which forces heated air into different rooms using a blower. If you’re an owner of a gas-burning furnace or if you’re thinking of purchasing one, it's very important to understand how they work.

Components of a gas furnace

Before you understand how a gas furnace works, it's important to know about the components which make up a gas furnace. A typical gas furnace has the following components.

Thermostat: The thermostat is a device that measures and controls indoor temperature. It is responsible for regulating the heating cycle of the furnace according to what is set.

Control board: The control board is a small circuit board which interprets the electrical signals coming from inside the outside the furnace. In response, it sends signals for various functions such as opening the gas valve or turning on the burners or fan.

Burners: Burners refer to small outlets where the gas is emitted and ignited to form controlled flames.

Igniter: The ignite of a furnace is responsible for lighting the gas emitted from the device. It causes ignition by creating a spark or producing an extremely hot surface which ignites the gas.

Blower fan: The blower fan is an internal electric fan and motor that directs warm air from the furnace to other parts of the room or home according to the heat demands of the occupants.

Flame detector: A flame detector is a device which is specially designed to prevent gas from building up dangerously in case the ignite malfunctions. If it happens, the flame detectors shut off gas flow if it doesn’t detect any heat.

Heat exchanger: The heat exchanger is a device which comprises thin-walled metal tubes to separate the combustion process from any air entering via the blower fan. Cold air is warmed before it is redirected into the home through the furnace.

How does a gas furnace work?

To understand the heating cycle of a gas furnace, we first need to look at the source of the gas. Natural gas furnaces use underground connections while LPG-burning furnaces need an outdoor storage unit. To understand how the furnace works, let’s see the following steps.

  • After the gas enters the device, the burner lights it.
  • The burning gas warms any cold air coming from the house into the furnace.
  • The exhaust pipes out the air out of the furnace through vents.
  • The warm air is then sent to various parts of the house using an exhaust pipe.
  • The blower fan then directs the warm air into various parts of the room, where the thermostat detects the requirement of heat.
  • The temperature of the internal air is increased gradually as warm air gets distributed. Cold air is pushed out and redirected to the furnace via return ducts.
  • Once the set temperature has been reached, the thermostat switches off the gas valve to stop the flow of warm air.


Gas furnaces have become one of the essential appliances for homeowners living in areas of colder climates or very cold winters. To get the most out of gas furnaces, homeowners should consider buying them from reputed and certified manufacturers and dealers only.

Views: 11

Add a Comment

You need to be a member of neofundi to add comments!

Join neofundi

Follow us on twitter  


© 2024   Created by neofundi.   Powered by

Badges  |  Report an Issue  |  Terms of Service