Most Mesa, Arizona, residents know the basics of how their home’s furnace works. However, if someone asked you to list the different components in your furnace, that might be a challenge. It is crucial for homeowners to clearly understand the heating cycle that happens in their home countless times each year.

One reason why you should be familiar with the process of how your furnace works is because it is part of your home’s entire HVAC system. When something breaks down, you will have a general idea of where the problem originates from and possible fixes for it.

The better you understand the inner workings of your HVAC system, the more committed you will be to regular maintenance and repair. This is because you will know how delicate certain components are and how expensive they are to repair if they are not properly maintained. This article aims to provide an overview of what your furnace does and how it works.

It Starts With the Heating Cycle

Your furnace has a cycle of operation. As technology has changed, some of the devices used in this cycle have become more modern. However, basic furnace technology has not changed for many decades.

It all begins with your thermostat. It detects the temperature in your home. Based on the temperature you have set; it sends a signal to your furnace for it to activate and begin heating the home.

If you look at your furnace and see that it has a pilot light, you likely have an older furnace. In older units, a pilot light would constantly burn. It would serve as the initial spark to light the fuel for the furnace burners.

Newer units have direct ignition sparks. You can think of it as the spark plug in a car. The most state-of-the-art units available use hot surface ignition. This is like how your car’s cigarette lighter works. Additionally, electric furnaces will use electricity and heated coils instead of burning fuel.

You can think of your electric furnace as a toaster oven. When you push down on the lever of your toaster oven, you start to see the coils in your toaster oven glow red. This is because they are heating up. That heat is transferred to your bread. With an electric furnace, the coils are heated. The heat that is produced is distributed throughout your home.

Irrespective of how ignition begins, your furnace will start to produce heat. The heat transfers to the heat exchanger if you have an old system. But this is not the most efficient way to do things.

Modern systems use a vent or motor that forces the heat from the burners to the heat exchanger at a controlled rate. The motor system will run for a precise amount of time, which is based on the amount of heat needed to warm your home.

When the furnace gas valve is open, gas flows to the burners. On the other side of the burner, there is a flame sensor. Its job is to guarantee that a flame is burning whenever there is gas flowing to the burners. If it does not detect the flame, the flame sensor will disconnect the gas. This is an important safety feature that will prevent gas from accumulating in your home.

You may notice that, when you turn your thermostat on, there is a slight delay before you feel warm air being distributed to your home. This delay is when the exchanger is warming up. Once the heat exchanger reaches the right temperature, the blower motor activates. Warm air will travel through your ductwork, and your home will start to warm up.

The heating cycle ends once your home reaches the desired temperature. Your thermostat will tell your furnace to initiate the shutdown process. Everything cools down and waits for another message from the thermostat to start the heating process again.

The Parts That Make Up a Furnace

You don’t need to be a professional technician, like those we have at Honest Air Conditioning, to know how every part of a furnace works. However, it would help if you understood the major components of a furnace. It is also good to know how they interact with each other. This will give you the ability to visualize the functioning of your entire furnace system.

Blower Motor

In addition to distributing heated air throughout your home, the blower fan will circulate cool air when your air conditioning system is running. This is the main reason why it is important to have heating and cooling systems that work well together.

Heat Exchanger

The heat exchanger is comprised of various metal tubes. This is where the heat from the furnace burners is held. The blower motor will force air across the heat exchanger and into your ductwork to warm your home.

Combustion Chamber

This is where the heat exchanger warms your air. It is an open space that allows air to move across the heat exchanger. It is essential that you keep your combustion chamber clean. This should be included as part of your regular maintenance.


Most people are familiar with the filter. But did you know that both your air conditioner and your furnace use the air filter? It filters the air that returns to your furnace. Since the air has been circulating through your house, it has collected dirt and dust particles.

There are several other smaller components of a furnace. But the ones that we have discussed are the most important in carrying out the heat cycle. Now that you understand how these parts work individually, you likely better understand how your furnace operates.

How Long Will Your New Furnace Last?

Some furnaces have been operating for 30 years or more. However, a furnace will usually last between eight and 10 years. If you maintain your furnace, it may serve you for 15 years or more. Several factors influence how long your furnace will work.

Maintenance is key. You need to have your furnace maintained annually after it is installed.

Regular filter changes are a must. It is recommended that you change your filter every six to nine months. The frequency with which you will make this change will depend on how much you are using your HVAC system and the air quality where you live. If you have pets, you might need to change your air filter monthly. A clogged filter puts strain on your heating system. Eventually, parts of your system will break down.

Enjoy Your Furnace

At Honest Air Conditioning, we know that few things feel as good as coming home to a working furnace on a cold winter’s night. We are proud to serve the HVAC needs of residents in Mesa, Arizona. Whether you need heating or air conditioning repair, maintenance, or installation, we are the team you should call.

We have been working in Arizona homes for more than a decade. We have an A+ Better Business Bureau rating and zero complaints. Call Honest Air Conditioning today. Let us help you make your home feel more comfortable.