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BTU Room Size Calculator

Estimate the cooling capacity (in BTU/h) needed for an air conditioner based on room size, ceiling height, insulation, sun exposure, and number of occupants. Uses simple rules of thumb — not a detailed HVAC design.

Enter room details

Measure length × width. For multiple connected rooms, use the combined area.

Standard ceilings are often around 8 ft. Higher ceilings require more BTU.

Rules of thumb often assume 2 occupants. Extra people typically add extra BTU.

Enter room area, height, insulation, sun exposure, and occupants, then tap “Estimate BTU” to see an approximate cooling capacity range.

Note: This BTU estimate is based on simplified rules of thumb (e.g., BTU per square foot) and adjustment factors. It does not replace a professional HVAC load calculation.