BTU Calculator
Calculate the BTU you need to cool a room with this free online BTU calculator. Size an air conditioner by room area, ceiling height, sun and occupants.
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How to use BTU Calculator
- 1Enter the room length, width and ceiling height in feet or metres
- 2Set how sunny the room is, how many people use it and whether it is a kitchen
- 3Read the BTU per hour, recommended air conditioner size, tons and kilowatts
Frequently asked questions
How many BTU do I need per square foot?▾
A common rule is 20 BTU per square foot for an 8 ft ceiling. A 300 sq ft room needs about 6,000 BTU; add 10% for a very sunny room and subtract 10% for a shaded one.
How many BTU is one ton of cooling?▾
One ton of cooling equals 12,000 BTU per hour, or about 3.5 kW. A 24,000 BTU unit is a 2 ton air conditioner.
Is a bigger air conditioner better?▾
No. An oversized unit cools quickly but shuts off before it removes humidity, leaving the room clammy. Pick the size closest to your result.
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