What Size Furnace Do I Need For a 1000 sq ft House?

If you’re looking to add a new furnace to your home, just know the square footage is not enough! It’s also important to take your climate into consideration before you make any estimations.

What size furnace do you need for a 1000 sq ft house?

Identify Your Climate Zone

The first step you should take is to identify your climate zone. If you live somewhere with harsh winters, it will obviously take a lot more effort for your furnace to function than if you live somewhere more forgiving in temperature.

There are seven climate zones, and you can look at the map below to find yours.

what size furnace do i need for a 1000 sq ft house?
Climate Zone Map From Office Of Energy Efficiency

Once we know which climate zone we’re dealing with, we can better calculate the size of the furnace that we need for our house or homestead! You can use the below numbers as estimates.

BTU for 1,000 sq ft House By Climate Zone

  • Zone 1: 30,000 BTU
  • Zone 2: 35,000 BTU
  • Zone 3: 40,000 BTU
  • Zone 4: 45,000 BTU
  • Zone 5: 50,000 BTU
  • Zone 6: 55,000 BTU
  • Zone 7: 60,000 BTU

As you can see, the BTU need varies drastically based on the climate you live in. So, make sure you know which zone you’re in before you make any plans – or you could get a nasty surprise when it’s time to buy!