Room Heating & Cooling Load
Rough heater and air-conditioner size (W and BTU/h).
Rule-of-thumb estimate – check the exact values for your situation.
Runs entirely in your browser. Nothing is sent anywhere.
How it works
- 1Enter your values.
- 2See the result update instantly as you type.
- 3Change any value to compare scenarios.
About this tool
Room Heating & Cooling Load: Rough heater and air-conditioner size (W and BTU/h). Type your numbers and the result is calculated instantly — no button to press, nothing to install. All math runs locally in your browser, so the values you enter are never sent anywhere.
Example
| Input | |
|---|---|
| Floor area (m²) | 25 |
| Ceiling height (m) | 2.5 |
| Insulation | Average |
| Sun exposure | Normal |
| People usually in the room | 2 |
| Result | |
| Heating power | 2,188 W |
| Cooling power | 2,500 W (8,530 BTU/h) |
How do I use the Room Heating & Cooling Load?
Enter your values. See the result update instantly as you type. Change any value to compare scenarios.
Is the Room Heating & Cooling Load free?
Yes. It is completely free with no sign-up, no usage limits and no watermark.
Is my data sent to a server?
No. Everything is calculated locally in your browser. Nothing you enter is uploaded, logged or stored.
Does it work on my phone?
Yes. It works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux — no app needed.