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📚 Guide
How much does a heat pump cost to run?
There’s no single number for what a heat pump costs to run — it depends far more on your home and your tariff than on the pump itself. Here’s what really moves the cost, so you can work out whether one would suit you.
Running cost is your unit rate, not a national average
A heat pump’s bill is its efficiency against the price you actually pay. Put in your postcode and I’ll show the real rates where you live.
- Efficiency is the whole game. A heat pump doesn’t make heat, it moves it —
so for each unit of electricity it delivers several units of heat. A well-installed system typically manages around
three units of heat per unit of electricity over the year (installers call this a seasonal efficiency, or SCOP, of
about 3), though it depends on the weather and how the system’s set up. The higher it runs, the less
electricity each unit of warmth costs you.
- Your tariff does the heavy lifting. A heat pump runs on electricity, which per unit costs more than
gas — so the deal you’re on matters enormously. A time-of-use or dedicated heat-pump tariff, where you
warm the home in cheaper windows, can change the sums completely.
Is a time-of-use tariff worth it? →
- A warm, well-insulated home costs less to heat. This is true of any heating, but heat pumps reward it
more: they work best delivering steady, gentle heat, which a draughty, poorly-insulated home fights against.
Insulation and draught-proofing aren’t just nice-to-haves — they directly lower the running cost.
Cheaper levers to try first →
- Flow temperature matters. The cooler the water a heat pump has to send round your radiators, the more
efficiently it runs. Bigger radiators or underfloor heating let it run at a lower flow temperature and cost less;
a system asked to run hot to keep up loses efficiency.
- Versus a gas boiler, in principle. Electricity costs more per unit than gas, but a heat pump gets
several units of heat per unit of electricity, where a boiler gets less than one unit of heat per unit of gas. So
whether it’s cheaper to run comes down to the ratio between your electricity and gas prices and how
efficiently the pump runs in your home — not a fixed rule.
Who does it suit? Homes that are reasonably well insulated, on (or willing to
move to) a tariff that suits electric heating, and happy with steady warmth rather than quick blasts. The only reliable
way to price it is against your home and usage, not a typical one — which is exactly what Joulely models,
free and impartial, with nothing sold. See which tariff suits
your usage →
Connect your meter — join the first 300 members
Coming soon: I’ll connect your smart meters and check every bill for you — from £1.50 a month while a meter is connected (£1.50 for one meter, £2.50 for gas and electricity), and you won’t be charged again after the month you disconnect. That is what buying the meter data costs me, and I’m billed one meter at a time. I take £0 commission if you switch. The first 300 members get 20% off, forever — £1.20 a month for one meter, £2 for two. Add your email and I’ll tell you first.
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Running cost weighed up on your home, not a typical oneSee how a heat pump’s running cost stacks up for your home — on your real usage and tariff, free and impartial.