UK Air Source Heat Pump Radiator Sizing BTU Calculator
Radiator output needed at lower flow temperatures.
Compare Your Options And Get Clear Answers
Radiator output needed at lower flow temperatures.
UK Air Source Heat Pump Radiator Sizing BTU Estimator
Enter your numbers below for an instant estimate.
How It Works
Key concepts behind this calculator
Enter Values
Fill in each field with your own numbers.
Calculate
Results update as you change the inputs.
Review
Read the breakdown and the explanation.
Adjust
Change values to compare scenarios.
UK Quick Guide
Typical values for reference.
| Room heat loss (W) | Flow temperature drop vs boiler (C) | Spare | Radiator output |
|---|---|---|---|
| 1500 | 20 | 0 | 7,165 BTU/h |
| 2500 | 25 | 0 | 12,795 BTU/h |
| 800 | 15 | 0 | 3,548 BTU/h |
| 1800 | 20 | 0 | 8,598 BTU/h |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
UK Air Source Calculator FAQ
Answers to common questions about this calculator.
It uses the formula shown with your inputs. Real conditions vary, so treat it as a guide.
Output needed rises as flow temperature falls
It is an estimate based on the inputs you enter. Check real quotes, labels or official guidance for important decisions.
Yes. Replace each input with your own figures and the result updates instantly.