Heating
What would changing your heating really cost to run?
Every system here is compared on the same amount of useful heat, so a unit of gas is never treated as a unit of electricity. Start with the figures you already gave in My Energy and change anything that isn't right for your home.
How your home is heated now
What that fuel is used for
Cooking and anything else is kept out of the heating comparison. These three always total 100%.
That works out as 7,671 kWh of useful heat a year — 6,460 kWh for the rooms and 1,211 kWh for hot water.
What you're thinking of instead
The prices used
Using the figures you gave in My Energy. Editing below changes this page only.
Where the money goes
| Each year | Gas boiler | Air source heat pump |
|---|---|---|
| Heating the rooms | £557 | £562 |
| Hot water | £104 | £144 |
| Cooking or other fuel | £35 | £0 |
| Gas standing charge | £106 | £106 |
| Total | £802 | £812 |
The new system would need 2,704 kWh of electricity a year to deliver the same heat.
What it does to the whole bill
Your electricity use would rise by roughly 2,704 kWh a year. Everything you don't use for heating is left exactly as it is, so nothing is counted twice.
Paying for it
On these figures the new system costs more to run, so there's nothing for the up-front cost to pay back. That can still be the right choice for other reasons — but it isn't a saving.
When the cost falls in the year
An illustrative pattern for the new system. Heating is concentrated in winter, so a monthly average hides the real shape.
Based on a fixed seasonal pattern (17% of space heating in January), with hot water spread evenly. Your own year will differ.
Worth knowing before you decide
- At your prices, a heat pump would need a seasonal performance of about 3.03 just to match your present running cost. You've assumed 3.00.
- You'd still pay the £106 a year gas standing charge, because the gas supply is being kept.
What your figures show
What if…
Move one assumption at a time and see what changes. Your saved baseline remains unchanged. Each slider changes one thing on its own.
Electricity price
26.11p
Changing only this would make the yearly extra cost about £10.
That's the same as your own figures.
Gas price
7.33p
Changing only this would make the yearly extra cost about £10.
That's the same as your own figures.
Seasonal performance
3.00
Changing only this would make the yearly extra cost about £10.
That's the same as your own figures.
Honest limits
- Seasonal performance varies a lot between homes, installers and winters.
- The split between heating, hot water and cooking is your estimate, not a meter reading.
- Installation costs vary widely and can only be settled by a survey.
- Insulation work usually changes the answer more than the system choice does.
Your heating figures are saved on this device only. No account, no email address, no quotes, no sales calls.
This clears only the heating settings saved in this browser. The saved heating comparison shown on the Tariffs page goes with it. My Energy, Solar, Battery and EV are untouched.
Performance assumptions start from 3 for an air source heat pump and 90% for a new gas boiler. Both are editable planning figures, not promises.
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Your saved figures will come with you.