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Peatson's Heating and Air Conditioning Ltd. Blog

Furnace Efficiency Ratings: AFUE & What It Means


So you’ve decided it’s time for furnace installation. Congratulations! The decision to spring for a new furnace is undoubtedly one that wasn’t made lightly.

Although the hard decision has been made, that doesn’t mean you’re completely done with making some choices when it comes to furnace replacement in Mississauga, ON. You’ll need to consider two important factors: whether you get a gas or electric furnace, and its AFUE rating if you go with gas.

An AFUE rating measures how efficient a gas furnace is. (It also measures furnaces that use propane and oil as a fuel source but in this blog we’ll be concentrating on gas.) The minimum AFUE is 95% which is already fairly high. Let’s take a look at how the AFUE ratings for furnaces differ between gas and electric models so you can be an informed consumer when you make this last decision regarding your new heating system.

Annual Fuel Utilization Efficiency

AFUE stands for Annual Fuel Utilization Efficiency and it’s the standard measurement for gas furnace efficiency. It’s expressed as the percentage of a furnace’s energy source it converts to heating power. A 95% AFUE gas furnace converts 95% of its gas into heat for the home and loses 5% to exhaust. As you can see, this is considered highly efficient.

Gas Vs Electric Furnaces & AFUE

Electric furnaces have a 100% AFUE rating. That’s because it uses electricity. You might be thinking that it can’t get any better than 100% so an electric furnace must be the best choice when it comes to saving energy and reducing utility costs. Right? Well, it’s not as simple as that.

AFUE is not a guarantee of energy savings because that percentage doesn’t account for the cost of energy. Electrical resistance heating doesn’t lose energy to exhaust because there is no exhaust. All the electricity is turned into heat as it moves through the heating elements. 

A natural gas furnace naturally loses some energy to exhaust gases and there’s no such thing as a gas furnace with an AFUE of 100%. What makes a difference is the cost of using electricity for heating compared to using natural gas. Electricity is usually more expensive, and this is why an electric furnace on average costs more to run over a season compared to a gas furnace.

Most homes that have a natural gas connection will opt for a gas furnace, not just because of the cost of gas compared to electricity, but because gas furnaces have higher heating power and the ability to heat your home more quickly than an electric furnace.

Choosing the Right Furnace

You may have the choice between a gas and electric furnace already made for you if your home doesn’t have access to natural gas. But you’ll still need to make other choices for a new furnace and you’ll need our professional assistance to ensure you end up with one that’ll suit your household for many years. 

Contact Peatson’s Heating and Air Conditioning Ltd. for reliable furnace replacement in Mississauga, ON.

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