What size AC do I need?

How do I calculate what size air conditioner I need?

The 5 Easy Steps

• Enter your home’s square footage
• Select geographic area
• Choose the number of occupants living in your home
• Enter number of windows
• Select your home’s level of insulation

So, what size central AC do I need? = 3 (X) tons! (The answer here)

disclaimer- This tool is a great reference for what size air conditioning unit your home needs but always be sure to consult with an HVAC expert for more information prior to undergoing any heating or air conditioning projects.

What Size of AC do I need?

7 Factors to Consider

• Square Footage of Home
• Geographic Region
• Occupants
• Window Quantity / Type
• Insulation (R-Value)
• Sun Exposure
• Ductwork Sizing

• Square Footage of Home- The primary factor when determining what size air conditioning unit your home will require is the overall square footage of the space.(Although, not all square footage is created equal.)
  • Ceiling Height: 1200 square foot home with 8 foot ceilings throughout will require significantly less cooling capacity than a 1200 square foot home with 15 foot vaulted ceilings.
  • Building Materials: A 1200 square foot home that has all vinyl siding will require significantly more than a 1200 square foot all brick home.

• Geographic Region– Areas of the country with long summer seasons will require more cooling, as do areas with a higher humidity.
• Number of Occupants– Human beings create body heat. The more people you have inside any given space, the more cooling will be required to offset that additional heat. (Ref. stat for human heat)
  • 1 person = 600 btu (pick a ref to outlink to)
  • 2 person = 1200 btu
• Window Quantity and Type– The total number of windows along with their R-Value will have a surprising effect on how much heat or cold they allow into the home.
  • Type of Windows- Single, Double, and Triple Pane
  • Glass Thickness
  • Material Type: Wood, Vinyl, and Aluminum
• Insulation (R-Value)– There are many different types of insulations that each are assigned a different R Value.
  • Higher R-Value = More Effective Insulation
• Sun Exposure– The total amount of time your home is exposed to or shaded from direct sun exposure also has an impact on the overall cooling capacity needed.
• Ductwork Sizing– Although sizing your equipment is important, it is equally important that your ductwork matches the capacity of your air conditioning system.
  Click for more information on Ductwork Sizing. (hyperlink to duct sizing page.)

It is extremely important to size your HVAC equipment properly to ensure it is capable of satisfying the heating and cooling needs of your specific home. HVAC Bee is providing this information as a quick reference guide for homeowners to gain a better understanding of those sizing requirements.

For more specific sizing information, consult your local HVAC Contractor to perform a detailed load calculation for your space.