Room Cooling BTU (Simple)
Estimate the cooling capacity your space needs using the quick 60 BTU per square foot rule of thumb—ideal for a fast check before you dive into detailed HVAC load calculations.
Consult a licensed HVAC professional for Manual J or Manual S load calculations before purchasing equipment. Building codes, climate zones, and duct design may require more detailed analysis.
Examples
- 275 ft² living room ⇒ 16,500 BTU/h (mid-size window AC)
- 180 ft² bedroom ⇒ 10,800 BTU/h
- 320 ft² studio ⇒ 19,200 BTU/h
- 150 ft² office with electronics ⇒ 9,000 BTU/h + extra for gear
FAQ
How accurate is this estimate?
It is a rapid sizing shortcut. Insulation quality, ceiling height, humidity, and internal heat sources can significantly change the true load—use a Manual J calculation for final equipment selection.
When should I size up the air conditioner?
Increase capacity for rooms with floor-to-ceiling windows, southern or western exposure, cathedral ceilings, or heavy electronics such as gaming PCs and servers.
Can I enter square meters instead of square feet?
Yes. Convert square meters to square feet by multiplying by 10.764 before entering the value, or change the rule to 645 BTU/h per square meter.
Does this rule include occupant heat?
It assumes two occupants. Add roughly 600 BTU/h per additional person who regularly uses the space to keep comfort levels steady.
Additional Information
- Rule of thumb: Cooling load ≈ Room area × 60 BTU per hour.
- Adjustments: add ~10% for sun-soaked rooms or large west-facing windows, subtract ~10% for shaded, well-insulated spaces.
- People and appliances matter—add roughly 600 BTU/h for each additional regular occupant beyond two, and consider equipment heat sources separately.