Room BTU Calculator
Calculate the exact cooling or heating capacity needed for your space.
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Estimated Capacity Required:
0BTUs per hour
Understanding BTU Calculations
A BTU, or British Thermal Unit, is a traditional unit of heat. It is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. When choosing an air conditioner or heater, the BTU rating tells you how powerful the unit is.
How We Calculate Your BTU Needs
Our calculator uses several variables to provide an accurate estimate. While a simple "20 BTU per square foot" rule works for basic estimates, true HVAC requirements depend on volume and environmental factors:
- Square Footage: The primary driver of heating and cooling needs.
- Ceiling Height: Standard calculations assume 8-foot ceilings. If yours are higher, the volume of air increases, requiring more power.
- Insulation: Poor insulation allows heat transfer, meaning your unit must work harder to maintain temperature.
- Occupancy: The human body radiates heat (roughly 600 BTU per hour). More people mean more heat to counteract.
- Kitchens: Appliances like ovens and stoves generate significant heat, requiring an additional 4,000 BTUs.
Typical BTU Requirements by Room Size
| Area (Sq. Ft.) | Capacity Needed (BTU/hr) |
|---|---|
| 100 to 150 | 5,000 |
| 150 to 250 | 6,000 |
| 300 to 350 | 8,000 |
| 400 to 450 | 10,000 |
| 550 to 700 | 14,000 |
| 1,000 to 1,200 | 21,000 |
Consequences of Wrong Sizing
Buying a unit with too many BTUs can lead to "short-cycling," where the unit turns on and off too quickly, failing to dehumidify the air properly. Conversely, a unit with too few BTUs will run constantly, increasing your energy bill while failing to keep the room comfortable.