A Guide to Picking the Right Size Furnace

• Air Products and Services
• 4 years ago
• Categories: HVAC
• Tags: Buying Guide, Furnace Size

A lot of homeowners make the mistake of buying the wrong size furnace, which can lead to unnecessary heating costs and uncomfortable temperatures. To help you pick the right size, the commercial AC maintenance experts at Air Products & Services show you how to estimate furnace sizes below.

Furnace Size and Indoor Comfort 

Furnace size indicates how much heat–measured in British thermal units (BTU)–a unit can produce in an hour. As a general rule, the bigger your home is, the more BTUs are required to heat it. Listed below are the estimated BTUs a furnace has to produce to warm various-sized homes:

• 1,200 square feet – 36,000 to 72,000 BTUs
• 1,500 square feet – 45,000 to 90,000 BTUs
• 1,800 square feet – 54,000 to 108,000 BTUs
• 2,100 square feet – 63,000 to 126,000 BTUs
• 2,400 square feet – 72,000 to 144,000 BTUs

Estimating the Right Size 

In addition to your home’s square footage, other factors can affect the optimal size of your furnace. For a more accurate estimate:

Measure the total area of the room – For irregularly-shaped rooms, divide the space into smaller sections and find the area of each section individually.

Determine the climate zone in which your home is located. In addition, it’s also important to know its corresponding heating factor. There are five climate zones in the US:

• Zone 1 – The country’s southernmost regions fall into this zone. The recommended heating factor is 30 to 35 BTUs.
• Zone 2 – Coastal California and the Southern cities of Atlanta and Little Rock are part of this zone, which has a heating factor of 35 to 40 BTUs.
• Zone 3 – Virginia and states to the west of it fall into this zone. The heating factor is 40 to 45 BTUs.
• Zone 4 – Boston, New York and Chicago fall into this climate zone, which has a heating factor of 45 to 50 BTUs.
• Zone 5 – The northernmost parts of the US have the highest heating factor at 50 to 60 BTUs.

Multiply your home’s square footage by your climate zone’s recommended heating factor to find out the number of BTUs needed to keep your house warm.

Keep in mind that this is just a rough estimate—there are other factors you’ll need to take into account as well. If you want a more accurate range, you’ll need to consult a residential AC contractor.

Looking for Residential Contractors in Your Area? 

Air Products & Services, a factory-authorized Carrier® dealer with nearly four decades’ worth of experience, offers a wide range of professional HVAC services, including air conditioning installation services. To get a free estimate on your new furnace, call us at (818) 989-2030 or leave us a message here. We serve homeowners in Tarzana, CA, as well as the surrounding communities.