What are the different types of furnaces?

What are the different types of furnaces?

We can guess why you’re here: you need a new furnace. You may have already read a number articles about the different kinds of furnaces but you’re no closer to figuring out which one is the best for your home. Why? Because most go into great detail about how types of furnaces work (coils, heat exchangers, inducer fans, pumps, etc.). When you’re browsing new cars at Tony Graham Toyota, you don’t necessarily need a detailed explanation of how the internal combustion engine converts gas into blah, blah blah… You just want help picking the right car for your needs and budget. The same goes for furnaces. Each has its own advantages depending on your needs.

The majority of homes in the Ottawa area have a “forced air” furnace. You know it as the appliance in the basement that forces air through ducts to the various rooms in the home. A thermostat controls the temperature for the entire house and keeps everyone comfortable. There are three main types of forced-air furnaces you need to know about; and we promise to make this really simple to understand:

Single-stage furnace

As the name suggests, this type only knows how to do one thing: turn on or off. When your house drops below your preferred temperature you set in your thermostat, the furnace turns on at full power. Once the target temperature is reached, the furnace shuts off completely. This cycle repeats constantly.

This is one of the most comment types of furnaces and likely the one you are currently replacing. If you aren’t noticing big swings in temperature or rooms that vary in temperature, this could be a less expensive option for your home. However, single-stage furnaces are typically noisier and there are often temperature differences as most homes do have duct distribution issues.

Two-stage furnace

This one is a bit smarter than the single-stage furnace in that it provides both high and low speeds. The two-stage gas valve in this furnace adjusts automatically to the heat load in the house to provide more comfort so the benefit is like have two furnaces in one. Our shoulder seasons (i.e. spring and fall) aren’t as cold as the winter so having a first stage has the benefit of quieter operation while the furnace works at lower speeds. As we get into the colder winter, the furnace then kicks into its second stage to operate at full capacity.

PRO TIP: make sure you also get a two-stage thermostat that quickly and automatically responds to the need for more heat when needed (and less heat when it’s not needed).

Modulating furnace

Sometimes called a “variable-capacity” or “multi-stage” furnace. For colder climates like we get in Ottawa, this is the optimal furnace for both efficiency and long-term cost savings. Working together with a manufacturer’s specific communicating thermostat, a modulating furnace monitors the temperature and adjusts minute-by-minute to keep things comfortable. The furnace will stay on longer at low capacities to increase the likelihood of quieter operation and consistent temperatures throughout the house. It knows how much heat is needed and only releases the right amount. The furnace circulates air to where it’s needed even when the process of heating has stopped. The modulating furnace is the most efficient product on the market.

PRO TIP: Pair a modulating furnace with a modulating air conditioner. Both work together in the same capacity for an ultimate comfort system that keeps your home comfortable year round. Not to mention it saves you a lot of money up front and in the long run.

ECM Motors

Whichever model you choose, make sure your new furnace comes equipped with an electronically commutated motor (ECM) motor. According to Natural Resources Canada, ECM motors can use up to 70% less energy than standard motors. This is the motor that blows the the heating and cooling around as well as circulate the air in your home. There is a bit more expense up front but remember that you’re buying a 16-20 year investment so the long-term savings are well worth it.

That’s it! Consider yourself educated on what’s out there. You may want to spend a bit more time digging into other furnace topics such as how long a gas furnace will last, AFUE ratings and high-efficiency furnaces.