How does a furnace work?

While a furnace generates the heat that warms your home, it works together with your thermostat and air ducts to heat your house.

Whether powered by natural gas or electricity, a furnace sits idle until the thermostat detects that the air is at a lower temperature than the current setting. The thermostat will send a signal to your furnace to fire up the burners and warm up the heat exchanger.

When the heat exchanger reaches the operating temperature, the blower is switched on. When this happens, the cold air that is brought in through the intakes is heated and sent through the ducts into your living spaces.

Natural gas furnace

Natural gas is the main energy source for Alberta households, making up 77% of household energy use in the province. Since a furnace can be your home's most used appliance when the temperature drops, natural gas furnaces tend to be the most popular. When compared to an electric furnace, a natural gas furnace tends to cost less to run because of the low cost of natural gas.

However, that doesn't mean natural gas furnaces are more efficient in the gas vs. electric furnace debate. You can compare the efficiency of different furnaces by their annual fuel utilization efficiency (AFUE), and equipment features.

Natural gas furnaces may cost more to install if you require additional installation or reconfiguration work. Gas furnaces also tend to be more powerful and may take less time to reach the desired temperature, thereby using less energy than a comparable electric model.

Electric furnace

Electric furnaces use resistance heating to create the hot air that warms your home. As such, it can be more efficient and could be less expensive to buy and install than a gas furnace.

When choosing an electric furnace, remember that electricity almost always costs more than natural gas, which means you'll spend more money for the same amount of heat you need in your home.

In colder climates, electric furnaces may be less efficient because they have to work harder to produce the necessary heat. This can lead to the furnace running longer and using more energy.

Modern furnaces

Whether if you prefer gas or electric, replacing an old and tired furnace with a modern ENERGY STAR® -rated model can reduce your energy usage, especially if you have a very old or malfunctioning furnace. Even if your existing furnace is in good working order, by replacing it with an ENERGY STAR rated gas furnace, you could use 6% less energy and save on your heating bills.

How do I optimize my furnace even more?

There are a few things you could do as a homeowner to optimize furnace energy usage.

First, ensure that you have an ENERGY STAR-rated furnace. For natural gas, this means that the furnace is at least 95% efficient, so you may be only losing five percent of your energy costs instead of the 20 or more that's possible with an old or outdated unit. Very old or malfunctioning units could be even less efficient, and you may save even more energy with a modern replacement.

Make sure you change or clean the filters on your furnace every three months or so to prevent buildup that could decrease efficiency - after all, a dirty filter is like a respiratory issue for your furnace.

Lastly, don't forget to do regular furnace maintenance. Most newer furnaces should be serviced every other year to prevent costly repairs and increase your furnace’s efficiency.