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How Many BTUs Does your Furnace Need?



Are you shopping for a new furnace in Guelph, Cambridge or Kitchener and surrounding areas? If you are, you’ll probably hear your HVAC contractor use the acronym BTU. BTUs indicate how effectively and efficiently your furnace will heat your home. How many BTUs do you need for your home? Read on.


What is a BTU?

BTU stands for British Thermal Unit. One BTU is the energy needed to raise the temperature of one pound of water by one degree Fahrenheit. The more BTUs a furnace has, the larger the area it can heat. However, bigger isn’t always better. If your furnace has insufficient BTUs, it’ll work non-stop and never keep your home at a comfortable temperature. Alternatively, a furnace with too many BTUs will frequently cycle and be inefficient.

BTU and House Size

40 to 45 BTUs can adequately heat one square foot of living space. For example, heating an average 1,500 square-foot (140 square-meter) home would require a furnace with around 60,000 BTUs. However, there are many more factors that affect a furnace’s operation.

Other Factors Impacting BTU Requirements

The number of BTUs you need also depends on where you live, the type of home you have and the age of your home.

  • Homes in cold climates require furnaces with higher-than-average BTUs to maintain a comfortable indoor temperature.

  • If your home faces south, you may require fewer BTUs because the sun will help warm your home. Likewise, in two-storey homes, the upstairs can have an insulating effect.

  • Homes with open floor plans may need a higher-BTU furnace because there are fewer walls to contain the heat.

  • If your doors and windows are old and inefficient, you’ll need a furnace with more BTUs than average. The same goes for older homes with inadequate insulation and poorly maintained ductwork.

  • Apartments and condos typically require fewer BTUs than houses because they have fewer exterior walls where heat can escape. Also, factor in the efficiency of the furnace itself. If you buy a high-efficiency furnace, it won’t have to work as hard to heat your home, and you can purchase one with lower BTUs.

Furnace sales, installation and repair in Guelph, Cambridge, Kitchener and Waterloo

Aire One Heating & Cooling is your trusted HVAC contractor in Guelph, Cambridge and the surrounding communities. We’ll help you choose the best furnace for your home, and we can also install it and help you keep it in top condition. With our Protection Plans, you can rest easy knowing our qualified technicians will maintain it for you. Contact us today to learn more about our home heating systems.

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