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Different homes have different needs. If your furnace is the incorrect size, you can end up with more expensive utilities or an insufficiently warmed house. A furnace that is too large for your home will continuously turn on and off, but a too-small furnace will never stop running.

Higher energy bills, overworked furnace, and uneven heating is not what you want in your home. You want your furnace to have a long lifespan and your home nicely warmed. Keep reading to find out how to find the best furnace size for your home.

Finding the Right Furnace

Along with different sizes, there are various types of furnaces: natural gas, propane, and electric. Most furnaces, besides electrical ones, require either a chamber or heat exchanger to warm the air. There are a few things that you can do to make sure your furnace is the correct size for your home. 

Square Footage

Square Footage & BTUs

Knowing the square footage of your home will help you decide which furnace to install. You can either find the square footage on paperwork you received when buying your home, or do the math yourself. BTU stands for British Thermal Units. One BTU equals the amount of energy needed to warm one pound of water by one degree Fahrenheit. 

Often, you will need roughly between 30 and 60 BTU per square foot. However, you need to remember that the climate you live in will affect this number. Colder climates will need more BTUs per square foot.

Here is a chart that you can use as a reference guide: 

Square Footage BTU Capacity
100-600 square feet 2000-12,000 BTU
700-1200 square feet 14,000-24,000 BTU
12,000-1800 square feet 24,000-36,000 BTU
1900-3000 square feet 36,000-60,000 BTU


However, it is vital to take into account the climate of the area you are in. If you aren’t sure about which furnace is best, or if you have questions about your current furnace, you can always contact MacLeod’s Plumbing and Heating.

Types of Furnaces

Gas Heater

You can get a few different types of furnaces for your home. We are able to service most furnaces, and can offer repair and installations. 

There are different pros and cons for natural gas, propane, and electric furnaces. Natural gas furnaces warm up quickly and the fuel costs are not very high. Propane furnaces are very versatile and last for a long time. The energy source of electric furnaces are always available and easy to install.

There are also a few cons with the different furnaces, as well. Firstly, natural gas furnaces are more expensive to install and run noisily. Secondly, propane heaters need regular inspections to make sure there are no leaks or corrosion that can create problems. Lastly, electric heaters have higher fuel costs when temperatures are low depending on the cost of electricity compared to gas.  

MacLeod’s Plumbing and Heating is here to answer all of your furnace questions. You can also read our blog about furnaces where we discuss how they work, the different types, and how to care for them to extend their life expectancy. 


If you do not feel that your home is getting the proper heating, you should look into your furnace size. A furnace that is too small for the area will be overworked, and a furnace that is too large will constantly turn off and on. Of course, neither of those options are ideal for heating your home efficiently. 

Look at our recommended chart, remember the climate in your area, and measure the square footage of your home to find the proper furnace size for you. 

MacLeod’s Plumbing and Heating

We have over 20 years of experience providing plumbing and heating services to Calgary and the surrounding area.

MacLeod’s offers high-efficiency furnaces that can save you money and last longer. They are able to remove moisture and perform with impressive air flow. With better filtration systems, you can breathe healthier air– only the best for you and your family!If you are having emergency issues with your furnace, such as a broken furnace in the winter or if it’s emitting the smell of gas, contact us right away. We offer 24/7 emergency services so you don’t have to worry about your home or your family.

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