How this window ac size calculator works
The calculator uses a 20 BTU-per-square-foot baseline at an 8-foot ceiling, then adjusts for ceiling height and sun/load level.
How to use it
- Room area. Enter the value in sq ft.
- Ceiling height. Enter the value in ft.
- Sun/load level. Enter the value that applies to your situation.
- Request the result. Add your email, then select “Email & show my result.”
What to do with the number
This estimate is intentionally approximate; rooms with kitchens, many occupants or poor insulation can need more capacity. Choose the closest standard unit size without dramatically oversizing the room.
Planning estimate
Use this result as a starting point, not a guarantee. Product specifications, site conditions, manufacturer guidance, local codes, taxes, labor, tolerances, and rounding can change the real requirement or cost.