HacksDomain

Housing & Building

BTU Calculator

Estimate a room’s cooling capacity in BTU/h, watts and tons.

Runs on your device · No input uploads

Your inputs

Sample values are ready to try. Replace them with your own.

Result

LOCAL

Enter your values, then choose Calculate.

How this tool works

A preliminary room-cooling estimate, using ENERGY STAR floor-area capacity bands for 100–2,500 ft² and an 8-foot ceiling, plus the selected adjustments. Shared boundaries use the higher band. This is not a Manual J load calculation. Ask an HVAC professional to account for climate, insulation, ceiling height and windows before buying equipment.

ENERGY STAR: room cooling capacity guidance