The Heat Pump Decision Journey
Should I replace my boiler with a heat pump?
A short path from last year's heating to a running-cost comparison and payback based on your own figures.
What you'll have at the end
Annual running cost for a heat pump and for your current system at your prices, the break-even SCOP, and a simple payback if you enter an installed cost.
The Journey
- 1
Step 1 — Guide
How much heat does my home use in a year?
Establish heat demand
Use annual heat demand from an energy assessment, or start from last year's gas, oil or LPG use and your current boiler's efficiency.
Read savings guide→ Then continue to step 2 - 2
Step 2 — Guide
Which efficiency figure should I use?
Find the right SCOP
Use the seasonal figure (SCOP) for the specific model at your heating system's flow temperature and climate, from its datasheet or installer — not a single-point COP.
Learn COP vs SCOP→ Then continue to step 3 - 3
Step 3 — Calculator
What will it cost to run compared with my current heating?
Compare running cost
Enter heat demand or fuel use, SCOP, your electricity price and your current fuel price and efficiency. The calculator shows both annual costs and the break-even SCOP.
Open Savings Calculator→ Then continue to step 4 - 4
Step 4 — Calculator
How long until it pays back?
Add installed cost
Enter the installed cost after any grant. Simple payback is shown only when the annual saving is positive.
Decision Summary
What you need for a heat pump decision
- Annual heat demand or last year's fuel use
- Energy assessment or fuel bills
- Model-specific SCOP
- Datasheet or installer, at your flow temperature
- Electricity and fuel prices
- Your bills
- Installed cost after grants
- Installer quotes
How to decide
If the expected SCOP is above the break-even SCOP the calculator shows, the heat pump costs less to run at those prices; if it is below, it costs more. Then compare any payback with how long you expect to stay.
Note: Running cost is sensitive to SCOP and to the ratio of your electricity and fuel prices. A heat-loss survey by a qualified installer is needed for sizing.
Journey complete
You now have your own figures to decide with.
Take your results to installer quotes and revisit the calculators when your inputs change. Each calculator shows its formula and the inputs it used.
Explore more heat pumps guides
Continue with another journey
Each journey below follows the same pattern: your own inputs, the right calculator, then the decision.