Calculate approximate BTU capacity needed for HVAC sizing at room level.
Overview
BTU estimates guide heating and cooling equipment selection for comfort and efficiency.
This calculator starts with area-based load and adjusts for occupancy and environment factors.
Professional load calculations are recommended for final equipment decisions.
Steps
Input length, width, and optionally height.
Choose conditions affecting heat gain or loss.
Adjust for internal heat sources.
Compute estimated heating or cooling demand.
Choose capacity near adjusted estimate.
Math
Estimated BTU approximately Area * BTU per sq unit * adjustment factors
A baseline area load is adjusted for insulation, sun exposure, occupancy, and climate.
Worked cases
150*20
About 3000 BTU baseline
300*20*1.15
About 6900 BTU
7000*1.1
About 7700 BTU
Why use this
Questions