Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Construction
HVAC BTU Calculator
Estimates the BTU per hour needed to heat or cool a room based on its size, ceiling height, and insulation quality. Use it to size an air conditioner, heat pump, or furnace before purchasing.
Fill in the required fields to see your result.
Construction
Roof Area Calculator
Calculate the true sloped surface area of a roof from its footprint dimensions and pitch angle. The slope multiplier (1/cos(pitch)) corrects for the fact that a pitched roof has more material area than the horizontal footprint it covers.
Fill in the required fields to see your result.
Key differences
| HVAC BTU Calculator | Roof Area Calculator | |
|---|---|---|
| Category | Construction | Construction |
| Inputs required | 3 | 3 |
| Result | BTU Required (BTU/hr) | Roof Surface Area (m²) |
| What it does | Estimates the BTU per hour needed to heat or cool a room based on its size, ceiling height, and insulation quality. Use it to size an air conditioner, heat pump, or furnace before purchasing. | Calculate the true sloped surface area of a roof from its footprint dimensions and pitch angle. The slope multiplier (1/cos(pitch)) corrects for the fact that a pitched roof has more material area than the horizontal footprint it covers. |