AC BTU Calculator

Air conditioners are sized by the Energy Star area table, then adjusted: add 10% for very sunny rooms, subtract 10% for shaded ones, add 4,000 BTU for kitchens, and add 600 BTU per person beyond two.

Bigger is not better. An oversized AC short-cycles: it cools the air fast but shuts off before dehumidifying, leaving the room cold and clammy — and wears itself out. Size to the table, not "one up to be safe."