How Does a Gas Furnace Work?

January 1, 2021

Gas furnaces are the most common method of heating homes — as well as commercial buildings — in the winter, even in Northern California. It’s likely what you have in your home, at the office building, and at many of the shops that you frequent. But in all the time that you’ve enjoyed the benefits of a gas furnace, you may not know how it works. It can be useful to know how your gas furnace functions so that you know when it needs repairs or replacement. If you understand how a gas furnace works, you’ll be able to spot when it’s not working.

How Does a Gas Furnace Work?

Gas furnaces were invented in 1919 by a woman named Alice Parker in Morristown, New Jersey. They became the first method of central heating used in homes and commercial buildings throughout the country and soon the world. Though they have evolved over time and become more energy efficient, they remain the most popular method of central home heating for a reason. But how do they work?

Turning Gas Into Heated Air

Gas furnaces heat your home through a method of gas conversion. The process begins by using either propane or natural gas in the furnace’s burner or combustion chamber to heat it. From there, that heat is transferred to the heat exchanger. As the air in your ducts blows over the heat exchanger, it warms through contact. The furnace then forces that air through the ductworks and out the vents, warming your home. In a nutshell, that is how your gas furnace works. But to truly understand how they work you must first understand the different types of gas furnaces that exist.

Types of Gas Furnaces

There are a few types of gas furnace systems that you can have installed in your home. Do you know which one is yours? They offer different benefits based on your climate and your heating needs.

• Single Stage Systems. These furnaces can be turned off and on, but offer no variation. They are popular in Midwestern homes where winters can be quite frigid, but less so in California homes with our mild winters.
• Two Stage Systems. Two stage systems offer both a low and a high setting to your furnace. On a mild winter night that’s only slightly irritating in its chill, a low furnace setting might give you just the amount of heat that you need…and it will call for less energy used.
• Modulating System. This is the most convenient type of gas furnace, which coordinates with your thermostat, using a variable-speed blower to offer just the amount of heat you want based on your thermostat setting. This can be perfect for Northern California homes.

What Does the Gas Furnace Need To Work?

Obviously, two of the most essential things that your furnace needs in order to work is the gas used and a burner. But there are more necessary components to a properly running furnace. Every furnace needs a duct system in order to circulate the supply of warm air. If you have a modulating system, you also need a thermostat in order to set the temperature. An air filter also helps the furnace not to become clogged with dust and debris, which can cause breakdowns or slower performance.

Why Size Matters

When it comes to having a functioning furnace, it’s especially important to have a furnace that is the right size for your home. If your furnace is too small, it might not be able to generate enough heat to fully warm your home on winter nights. This could mean that you could be paying high heating bills as your furnace is working at maximum capacity, even though you still feel drafts in your home.

On the other hand, if your furnace is too large, the heated air could too quickly warm your home. When your furnace is connected to your thermostat, it will shut off once it reaches the ideal temperature. If your furnace is too large, it reaches the ideal temperature too quickly, shuts off, and turns back on again soon after. This could lead to your furnace being overworked and developing wear and tear, in addition to the discomfort of rapid temperature changes in your home.

The right furnace professional will carefully inspect your home during the preliminary estimate so that they can find the furnace that’s the perfect fit for your home. The right furnace size can be the difference between energy efficient comfort and pesky repair and replacement costs.

Problems Your Gas Furnace Might Encounter

Now that you know how your gas furnace works, it’s important to know what could go wrong. These problems can occur as a result of a lack of furnace maintenance, age, or — as stated above — the wrong size of furnace. Here are a few issues your furnace could encounter and the likely cause behind each.

• Collection of dust. If your furnace has a strong smell when you turn it on, this could mean that too much dust has gathered on the surface. This can be a result of a lack of maintenance. Dust accumulates due to months of inactivity, and if the furnace isn’t cleaned off before it can turn back on, the smell of burning dust can be unpleasant. It could also mean that your air filters need to be replaced.
• Flickering pilot light. The yellow pilot light is there to warn you if something unhealthy is in the air. If it is flickering, this likely means there’s an excess of carbon monoxide, which should be addressed immediately.
• Loud banging. Sometimes your furnace makes loud noises when it’s first turned on, but if this persists, it could be that your burner is clogged and should be cleared before you move on.

Does your furnace need repairs? Are you looking for a new furnace that can better serve your home? Service Champions can help! Contact us today to learn more about a new furnace, as well as furnace repairs or how to join our MVP plan so you can enjoy annual tune-ups.