Many homeowners here in South Louisiana rely on a gas furnace for their winter heating. Natural gas furnaces are among the most affordable and reliable heating systems available. In this article, we’ll review how gas furnaces work, the major gas furnace parts, and why a gas furnace may be a good fit for your home.

Need a new heating system here in Morgan City, Houma, or Thibodaux? We’re the team to call. Get a free in-home estimate from the NATE-certified heating professionals at Bob’s Heating & Air Conditioning.

The gas furnace basics

Gas furnaces use controlled combustion to generate heat energy, which is then transferred to indoor air. The blower then pushes this heated air through the air ducts of your home, distributing it to different rooms. Combustion byproducts and gases are emitted outside through the flue pipe.

A gas furnace’s efficiency is measured by its Annual Fuel Utilization Efficiency, or AFUE. Essentially, AFUE represents how much of the fuel (natural gas) is successfully turned into heat energy. The higher the percentage, the more efficient and less wasteful the furnace is. For example, an 80% AFUE furnace converts heat out of 80% of its fuel, with 20% being wasted.

Gas furnaces are distinct from both electric furnaces and heat pumps. Instead of combusting fuel, electric furnaces push air through heated electric coils to rapidly warm it. Think of an electric furnace like a giant hairdryer. In contrast, heat pumps utilize a completely different technology to heat your home. Instead of generating heat, heat pumps pull residual heat energy out of the outside air and bring it into the home. Heat pumps are actually capable of both cooling your home in the summer and heating it in the winter by simply reversing the process for each season.

Get to know your gas furnace parts

No matter the make or model, all gas furnaces have a few basic components that allow them to function.

1. Gas Burner

The gas burners in your furnace ignite natural gas as part of the combustion process. This makes them one of the essential gas furnace parts.

The gas burners in your furnace ignite natural gas as part of the combustion process. This makes them one of the essential gas furnace parts.

Most gas furnaces have an active pilot light inside of the gas furnace. When your home’s thermostat turns the furnace on, gas is slowly fed into the burner. This light ignites the natural gas, rapidly heating up the chamber. As you might imagine, this is a controlled process: a critical safety component known as the flame sensor ensures that combustion is occurring, so that there is no excess buildup of gas inside of the furnace.

As furnaces age, their combustion process becomes less efficient. That’s just one of the warning signs you need a new gas furnace.

2. Gas Manifold

Another one of the most important gas furnace parts is the gas manifold, which connects burners with the gas valve. Brass fittings called spuds connect the burners to the manifold. The amount of gas that is transported to the gas burners depends on the size of the hole drilled in the manifold.

Comparatively, this part requires little maintenance and care as compared to other components of the gas furnace. Still, when you schedule a furnace tune-up with us, we’ll take a look to make sure your gas manifold is still operating properly.

3. Heat Exchanger

The heated air inside of the burner chamber cannot simply be pushed into your home. Just as in your car, combustion creates gas byproducts that are not safe to breathe indoors. It’s for this reason that the combustion process happens on one side of the heat exchanger, with your home’s indoor air on the other. Air is pushed through the heat exchanger—which resembles a set of coils or tubes—which rapidly heats due to the heat on the other side. This air is then pushed by the blower through ducts into your home.

The heat exchanger plays a vital role in preventing indoor air and combustion air from mixing. This is why a cracked heat exchanger is bad news for your home. While such scenarios are rare, a cracked heat exchanger may allow flue gases like carbon monoxide to get into your home’s air.

Be sure to check out this blog post to learn more about the common warning signs of a gas furnace breakdown.

4. Blower

All forced-air HVAC systems feature a blower unit—this is where the “force” in “forced-air” comes from, after all. The blower pushes the heated air from the heat exchanger into the ductwork of your home. This superheated air then travels through the ducts to vents and registers in individual rooms, where it begins to change the temperature of each room to match the goal indicated by the thermostat.

Here’s something all homeowners should know: the blower, whether being used for the air conditioner in the summer or your furnace in the winter, requires adequate air intake to function. Be sure to clean your HVAC air filter regularly. As this filter clogs with dirt, dust, pet hair, and more, it allows less fresh air into the ducts.

5. Thermostat

Thermostats control the temperature in your home. You can use them to adjust the temperature according to your comfort level. When you turn up the thermostat, the flame of the gas burner gets larger (via the gas burner), increasing the temperature. On the other hand, when you turn down the thermostat, the flame shrinks, lowering the temperature.

While not strictly part of your gas furnace, your thermostat is the key to controlling it. This makes is one of the most essential gas furnace parts.

While not strictly part of your gas furnace, your thermostat is the key to controlling it. This makes is one of the most essential gas furnace parts.

Thermostats use a temperature sensor to gauge the current temperature of your home. For this reason, you should place the thermostat in the center of your home to ensure that your furnace heats the home evenly. Placing a thermostat near a window or exterior wall may lead to it misjudging what the overall temperature in the home is.

Smart thermostats

On a final note, you’ve probably heard about smart thermostats. Also known as programmable thermostats, these upgraded thermostats allow you to automate and set your home’s temperature ahead of time. This helps you avoid the all-too-common situation where you accidentally leave the heat on all day while you’re away at work.

Smart thermostats can help you save money and live more comfortably. They also reduce the overall wear-and-tear on your gas furnace parts.

Have our team inspect your gas furnace this fall

There are many gas furnace parts, but each needs to be working together at their best to produce even, effective, and efficient heating for your home. With furnace maintenance from the expert techs at Bob’s Heating & Air Conditioning, we’ll make sure that each part is checked individually and ensure that they’re all working cooperatively for the best possible comfort and energy savings.

To schedule your heating tune-up here in Morgan City, Houma, and Thibodaux, call our team today. Have other questions about your gas furnace or its components? Let us know how we can help!