What Does a Furnace Do?

Hello there, HVAC enthusiasts, and homeowners! Today we’re tackling a fundamental question: what does a furnace do?

For many, the answer may seem simple. But when we delve into the details, we find there’s a lot more to our trusty furnaces than meets the eye.

They not only provide us with warmth in the cold seasons but also play a critical role in our overall HVAC system. So, let’s explore the world of furnaces, their types, how they work, and what they can do besides heating.

Summary of What a Furnace Does

In essence, a furnace is a heating system that warms your home during colder weather. It burns fuel to produce heat and then uses a blower fan to distribute this heat throughout your home.

However, modern furnaces are far more complex and versatile than their predecessors.

Types of Furnaces

There are various types of furnaces that homeowners can choose from, depending on their specific needs, climate, and budget.

Gas Furnaces

Gas furnaces are a common type of furnace that burns natural gas to produce heat. They are known for their efficiency and are typically cost-effective in terms of energy usage.

Electric Furnaces

Unlike gas furnaces, electric furnaces use electric heating elements to generate heat. While the cost of electricity can be higher, electric furnaces are usually cheaper to install and maintain.

Oil Furnaces

Oil furnaces use heating oil to create heat. While not as common as gas or electric furnaces, they can be a good alternative in areas where natural gas is not readily available.

Propane Furnaces

Propane furnaces, like gas furnaces, use a gas — propane, in this case — to generate heat. These types of furnaces are typically used in rural areas where natural gas lines are not available.

Natural Gas Furnaces

Natural gas furnaces are a popular choice among homeowners due to their efficiency and the widespread availability of natural gas.

Heat Pumps

Heat pumps work by transferring heat energy from one place to another. In the winter, they draw heat from the outside air or ground and transfer it inside your home.

High-Efficiency Furnaces

High-efficiency furnaces, often called condensing gas furnaces, can convert 90% or more of the fuel they burn into heat, making them a highly energy-efficient choice.

Heating Processes and Components of a Furnace

Let’s delve a bit deeper into the heating process and components of a furnace.

Fuel Source

The fuel source, whether it’s gas, electricity, oil, or propane, is what the furnace uses to generate heat.

Combustion Chamber

In the combustion chamber, the furnace burns the fuel source to create heat.

Heat Exchanger

The heat exchanger is a key component that transfers heat from the combustion chamber into the air that will be circulated throughout your home.

Air Handler

The air handler houses the blower fans and other components that move the heated air through your heating ducts and into your home.

Blower Fans & Motors

Blower fans and motors are what push the heated air from your furnace into your home’s ductwork.

Does a Furnace Only Heat?

While the primary function of a furnace is to provide heat, many modern furnaces play a larger role in the home’s HVAC system.

Does a Furnace Heat Water?

Some types of furnaces, known as combination furnaces, can also heat water for use in your home. This can make them a cost-effective and efficient choice for homeowners.


A furnace is an essential component of your home’s comfort system. Not only does it provide you with warmth in the cold season, but different types of furnaces can also cater to various specific needs, including heating water.

However, they are complex machines with many components that all work together to heat your home.

Regular maintenance and annual inspections are key to ensuring that your furnace stays in good working condition for years to come.

Understanding your furnace can help you maintain it better and even save you money in the long run. If you’re ever in doubt or in need of assistance, always reach out to a professional HVAC technician for help!

About Roy Cohen

Roy Cohen has a burning passion for heating, cooling, and ventilation. He aims to help you save money on expensive repairs and bring you the best HVAC products. He has years of experience behind him in HVAC repair and garage maintenance.

You can find Roy at his LinkedIn or his email: [email protected]

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