Furnace Repair Brampton

How Do Gas Furnaces Work

How do gas furnaces work?

Gas furnaces are heating appliances that use gas as their energy source. But, how do gas furnaces work? Before you can buy a gas furnace, you ought to understand how it works so that it’s easy to handle and maybe know how to rectify it if there is a simple problem.

Unlike other furnaces which generate heat and distribute it to the parts of the room either by electricity, burning coal, oil, or propane gas, this one burns natural gas to generate the heat. The way it is structured is usually very different from all the others.

What Is a Gas Furnace Made Up of?

The first step in understanding how a gas furnace works is usually understanding its parts. Now a gas furnace has different features which have other purposes, and they include the following:


The burners are the main parts of the gas furnace. They are small gas outlets whose work is to let out controlled amounts of gas ignited within the furnace to produce heat.


These are small devices that work through emitting sparks to ignite the gas from the burners to produce heat. Their main job is to create a spark to ignite the gas which burns inside the furnace.

Flame detectors

A small device inside the furnace is there to control build gases if there is no flame. For safety purposes, if the gas comes out and there is no flame detected, it is automatically shut off so that it does not build up dangerously.


It is a device that controls the heating cycle. It does this by measuring and managing the heat supply in the room.

Control board

It is a purely electric appliance that receives and works according to electrical signals generated from the air supply system and temperature from the furnace. It controls everything in the system and manages all the operations.

Heat exchanger

The heat exchanger controls the heat generation and transfer between the inside and outside of the furnace. They are tubes that separate the heated air from the supplied one.

Gas valve

It has a simple function of regulation where it regulates the flow of gas from the source.


It is the part that regulates the flow of electricity into the furnace. The function of this is to control the electric current to the correct voltage.

The Heating Cycle

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The heat cycle is the system of heat generation and circulation within and around the furnace to produce hot air directed to parts of your house to make the temperature bearable and suitable for staying.

It all begins from the pipe that supplies either propane or natural gas to your house. The gas goes through to your furnace through the inlet pipe. Then, the igniter sparks, which starts a small flame inside the furnace. This flame is responsible for heat production. Now, cold air enters the furnace, where the heat exchanger warms it up.

The vent then channels out the exhaust gases from the combustion process. The blower fan will then direct the warm air to various parts of the house. The blower fan depends on the thermostat to supply varying amounts of heat into the room.

Once the maximum temperature reaches its peak, the gas flow is inhibited to prevent the burning of more gases. It goes on and on to control the air temperature around the room.

All these parts work together to achieve the heating cycle. When any of them gets faulty, the whole system might fail to work. You, therefore, need to do the necessary maintenance routines and clean the parts that get dirty to maintain the flow of warm air in the room.

How Do Gas Furnaces Work – The Air Regulation System

The heat from the burner inside the furnace is usually regulated through the blower fan and the thermostat. The thermostat measures the air around the house to dictate whether it should emit more or less warm air to the surrounding.

The air contaminated from burning gas inside the furnace is then directed and emitted to the outside. The air inside and within the heating system is usually regulated to make sure there is balance.

The gas furnace usually works by supplying hot air into the room through the blower fan and returning the heated cold air through the return ducts, creating a constant exchange of cold and warm air between the inside and outside of the furnace.

The heat generated is forced out of the unit by the blower fan. The air filter traps any contaminants in the air. The constant supply and exchange of the gases create the regulating effect that makes the temperature bearable in the house.

The Electric System

The electric system of the gas furnace mainly contains the transformer, the control board, and the igniters. Each one of them has its purposes, but they share the same power line. The igniter generates a spark to ignite the gases when the system is turned on.

The control board controls every activity within the whole unit, and the transformer regulates the voltage of the electric power coming into the unit. The electric system is part of controlling the flow and exchange of air inside and outside the furnace.

How Do Gas Furnaces Work – Conclusion

The gas furnace composes of different parts which work together to control the temperature inside the house. The air regulation system is the main one, but it depends on the burning of natural gas or LPG to produce the heat, which heats the air and warms up the room.

It is usually essential to know the parts, how they function and what you need to do with any of them for the system to work. You need to make sure the very aspect of the system are working to regulate the air inside the house.

How do gas furnaces work? You will answer this question when you understand each detail of the whole system like we have just done. Knowing it is essential to know what to do in case one part breaks down.