Home › Home & Yard
BTU Calculator
Estimate air-conditioner size in BTU/h, kW and tons from room size, sun, occupants and kitchen use.
How it works
Base = 20 BTU/h per ft², ±10% for sun or shade, +600 BTU/h per person beyond two, +4,000 BTU/h for a kitchen. These rules of thumb follow the ENERGY STAR room air-conditioner sizing guidance. A Manual J load calculation is more accurate for whole homes.
Examples
- 500 ft² room, normal sun, 2 people = 10,000 BTU/h (2.93 kW).
FAQ
Is bigger better?
No. An oversized AC short-cycles and removes less humidity.