Furnaces Explained – Choosing the Right Heating Solution

Furnaces heat your home’s air using different types of fuel. Understanding how furnaces work will help you choose the right heating solution to keep your home warm and cozy throughout winter.

Electric furnaces use coils and a blower fan to distribute heated air throughout your home. They are a good option when natural gas service is unavailable.

How They Work

Furnaces work to heat and distribute air in your home. They are the most common types of heating systems and operate on gas, oil or electricity. They can also be used in combination with a heat pump system to provide optimal comfort.

When the thermostat detects that the indoor temperature has fallen below your set point, a signal is sent to the furnace circuit board, which activates the burners. The furnace’s blower fan draws in air from the outside through a vent and mixes it with the fuel to create combustion. The flames heat a metal heat exchanger that transfers the heated air to passing ductwork. The flue and vent pipes exhaust any by-products of the combustion process to the outdoors.

When the furnace senses that your home has regained its set temperature, the blower fan shuts off. The pilot light or electronic ignition (depending on the furnace model) stays lit to keep the system warm and ready for the next time your thermostat signals it to start up.

Choosing the Right Fuel

Furnaces generate and distribute warm air to homes through ducts. They can be powered by a variety of fuel sources including natural gas, propane, heating oil, and electricity.

The heating process begins when a thermostat triggers the furnace system to turn on. A gas valve opens to bring in gas from the supply line (which could be connected to an outdoor storage tank for LPG or the natural gas pipeline on your property).

A burner inside the furnace combusts the gas, creating heat energy that is pushed into your home through air ducts and vents. The heat energy is then distributed throughout the home by a blower fan.

Furnaces that use natural gas tend to be the most common choice. This is because the fuel works hard to warm your home while offering lower emissions and costs compared to other energy options. Two-stage burners offer additional efficiency benefits by giving the furnace three operating settings, instead of just on or off.

Choosing the Right Size

Furnaces come in a wide variety of sizes. It’s important to find a furnace that will be appropriately sized for your house or building to avoid overworking the system and increasing energy costs.

The size of your house or building will determine what type and how many BTUs (British Thermal Units) your furnace should produce. This number can be found on blueprints or in closing documents, but you can also calculate it yourself by measuring the square footage of your home or building and multiplying it by 25.

The other factor influencing the right furnace size is your heating needs and how well your home is insulated. A well-insulated two-story house will require fewer BTUs than a one-story house because it better retains heat. A poorly insulated house will require more BTUs because the furnace will have to work harder to keep up with your thermostat settings. Having an efficient furnace will help reduce utility bills, improve comfort, and prevent unnecessary wear and tear on your system.

Choosing the Right Thermostat

Furnaces are large heating appliances that heat air, water or steam then distribute it to various parts of a building. They can use a variety of fuels including electricity, oil, propane gas, and natural gas. Almost all furnaces are forced-air systems that use a blower to direct heated air throughout the home.

When the thermostat senses that the indoor temperature has fallen below the set point, it will send a signal to activate the furnace system. The gas valve will open and the burners will ignite. The resulting exhaust gases will be vented out of the house through a flue pipe.

If the fuel source is oil or propane, a pilot light will remain lit. If it is natural gas, the valve will open and a spark will ignite the burners. The hot gas will heat a metal heat exchanger, which in turn warms the cold air being blown through it. Once the desired temperature has been achieved, the blower will shut off.