Home & DIY
BTU calculator (AC/heating)
Area + height → AC/heating power in BTU and kW.
- Instant
- Free
- Private (processed locally)
- No sign-up
Size an AC or heater
Enter the room area and ceiling height. The tool estimates the power in BTU/h and converts it to kW.
The method
- ≈ 215 BTU/h per m² (2.5 m base)
- Adjusted for the real height
- kW = BTU/h ÷ 3,412
- Increase for strong sun / poor insulation
Example
| Input | Value |
|---|---|
| Area | 25 m² |
| Height | 2.5 m |
| Power | ≈ 5,380 BTU/h |
| In kW | ≈ 1.58 kW |
Indicative estimate: the real value depends on insulation, exposure and climate. 100% local calculation.
Frequently asked questions
What is a BTU?
The BTU (British Thermal Unit) measures an amount of energy; in air conditioning we use BTU/h, a power. 1 kW ≈ 3,412 BTU/h.
How many BTU per m²?
As a rule of thumb, about 215 BTU/h per m² for a 2.5 m ceiling. The tool scales proportionally to the height.
Is this estimate enough?
It is a ballpark. Insulation, sun exposure, number of windows and climate noticeably change the real need.
How do I convert to kW?
Divide BTU/h by 3,412. For example 5,382 BTU/h ≈ 1.58 kW.