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Furnace fficiency rating of Household

If you’re in the market for a new furnace, it’s a good idea to know about AFUE ratings. AFUE stands for annual fuel utilization efficiency and is a rating that determines a heating system’s efficiency. Here’s what you need to know.


AFUE ratings are measured in percentage. They indicate how much of your furnace’s fuel is converted into heat to warm your home. Consequently, a furnace with a high AFUE rating is more efficient than a furnace with a low rating. For example, a furnace with an AFUE rating of 85 converts 85 per cent of its fuel (natural gas, electricity, or oil) into heat and only wastes 15 per cent.

You can find your furnace’s AFUE rating next to its British thermal unit (BTU) rating, which measures the unit’s heating power. For instance, a furnace with 80,000 BTUs is large enough to heat a 1,600 square foot home. However, a system with 80,000 BTUs and an AFUE rating of 90 per cent only delivers 72,000 BTUs of heat to your home. Minimum AFUE ratings in Canada

AFUE ratings typically range between 80 and 100. However, the Canadian government recently updated its regulations. Consequently, any furnace manufactured since July 2019 must have a minimum AFUE rating of 95 per cent. In the United States, the minimum AFUE is 80 per cent.

AFUE and your Energy Bills

A furnace with a high AFUE rating can have a dramatic impact on your energy costs. If you have a furnace that’s 15 to 20 years old, it probably has an AFUE rating of around 80 per cent. However, furnaces become less efficient as they age. Therefore, if you have an old heating unit, it’s likely not as efficient as its AFUE rating indicates. Consequently, replacing your existing furnace with one that has a high AFUE rating could significantly reduce your energy bill.

Features of high AFUE furnaces

Manufacturers use new technology to make their furnaces more efficient. Here are some of the features of high AFUE-rated furnaces.

  • Secondary heat exchanger

  • Variable speed blowers

  • Variable heat output

  • Direct spark or hot surface ignition systems to replace pilot lights

  • Improved filter systems

If you need help choosing the right furnace for your home, the team at Harmony Heating & Air Conditioning can help!

Furnace installation and repair in Calgary

At Harmony Heating & Air Conditioning, we carry high-efficiency furnaces from leading brands like Lennox and Trane. We provide a full range of heating services and offer a comprehensive home protection plan. Our technicians are available to install, maintain and repair your home’s heating system 24/7. Contact us today to get a free, no-obligation quote.


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