Room BTU Calculator

Estimate the heating capacity needed using 25 BTU per sq. ft. for hot water and 2-pipe steam systems, or 20 BTU per sq. ft. for 1-pipe steam systems, with adjustments for ceiling height, windows, climate, and room exposure.

This calculator uses 25 BTU per square foot for hot water and 2-pipe steam systems, and 20 BTU per square foot for 1-pipe steam systems. Rooms with large windows, high ceilings, unusual construction, or significant heat loss may require a professional room-by-room heat-loss calculation.