What Size Furnace Do I Need?

A new build home will need afurnace, and they also don’t last forever, so maybe your old furnace needs replacing. In any case, you may be askingwhat size furnace do I need?Planning out anHVACsystem can be complicated, but this is a calculation that anybody can do. You need a few bits of data and the formula.

How to Size a Furnace in Terms of BTU’s

The calculation depends on your climate for pretty obvious reasons. If you live in a cold place, you’re going to need more muscle to get the job done. If you live in the sunbelt, you probably won’t need as much. The United States is a huge country in terms of geographic size, which means many different climates.

what size furnace map of United States based on BTU output needed

If you live in thelow desertor thesoutheast, you only need30-35 BTUsper square foot.
Coastal Californiarequires about35-40 BTUsper square foot.
Homes in thecoastal Pacific northwestneed about40-45 BTUsper square foot.
Thehigh desertrequires45-50 BTUsper square foot.
If you live in themiddle mid-west(as opposed to the north mid-west) or中东coast, you will need anywhere from40-50 BTUsper square foot.
Theupper mid-west,New England, andAlpineareas require a whopping50-60 BTU’sper square foot.

Once you’ve determined what climate you are in, all you have to do is take that recommended number and multiply it by the square footage of your home.

Furnace Size Calculation Example

Say you live in the high desert in a 2,000 square foot home; your calculation would look something like this on the low side:

45 BTU’s per square foot x 2,000 square feet = 90,000 BTU’s

On the high side:

50 BTU’s per square foot x 2,000 square feet = 100,000 BTU’s

You’re going to have to make an executive decision about whether or not you want to play it safe or play it cheap and pick somewhere in that range.

Find Furnace Parts at PlumbersStock

Now that you know what size furnace you need in terms of BTU's, it's time to make other considerations before making a purchase. Check out all our helpful resources. We carry a huge inventory ofHVAC partslikeblowers,furnace ignitors,blower wheels, etc. Did you know that you can find member pricing here on certain items (typically name brand, MAP priced items) if you log in? For industry professionals buying in bulk, please consider contacting us directly for extra special pricing and extra savings.