UK System Boiler vs Combi Boiler Water Pressure Calculator
Flow rate comparison for a combi and a system boiler with cylinder.
Compare Your Options And Get Clear Answers
Flow rate comparison for a combi and a system boiler with cylinder.
UK System Boiler vs Combi Boiler Water Pressure 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.
| Combi output (kW) | Temperature rise (C) | Outlets in use | Combi flow |
|---|---|---|---|
| 30 | 35 | 2 | 12.3 L/min |
| 35 | 40 | 1 | 12.5 L/min |
| 24 | 35 | 2 | 9.82 L/min |
| 28 | 40 | 3 | 10.0 L/min |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
UK System Boiler 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.
Flow = kW x 60 / (4.19 x temperature rise)
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.