There are a wide variety of residential gas furnaces available in different sizes. With a few basic calculations, you can get a rough estimate of the size of furnace your home needs, but it is strongly recommended that you consult with an experienced heating and cooling specialist before making a purchase.

How much square footage does your home have? Measurements for rooms that you do not plan on heating and cooling, like sunrooms, patios, workshops, and garages, should be excluded from your calculations. Measure how high your ceilings are. Most sizing charts will assume that your home has 8 foot ceilings. If the ceiling height in your home is different, you need to make a note of that.

Think about the type of climate you live in, each season’s length, and the high and low temperatures. For example, Dallas, Texas is known for its hot, arid weather; although, other parts of the state experience all four seasons. As a general rule, the colder the winters are, the bigger size of furnace you will need.


Consult with a furnace installer or manufacturer to determine the appropriate size of furnace for your home. However, be aware that installers and manufacturers don’t always use the same sizing and recommendation charts.

Talk to a heating and cooling expert for load calculations and recommendations before choosing a furnace size. Although recommendation charts offer a great starting point, there are a number of other factors you must take into consideration, like the construction and age of your home, how much insulation your home has, and the quality of your doors and windows.

Before choosing a furnace to buy, look to the expert staff at AJR Heating, Air Conditioning, and Refrigeration, Inc.! We pride ourselves on being our clients’ number one choice for all of their furnace installation and furnace maintenance, and we look forward to the opportunity to work with you. Contact us today!

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