Heat Pump Estimate

Heat pump vs gas boiler

Heat pump or gas boiler — an honest comparison

No spin. Here's how heat pumps really compare to a gas boiler on running costs, comfort, carbon and upfront price — including where a heat pump doesn't win. Then estimate the numbers for your own home.

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Figures verified June 2026 · re-checked at each update

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The honest version on running costs

This is where a lot of heat pump marketing oversells. The truth depends entirely on what you heat with now:

  • Replacing mains gas: running costs are usually close to neutral. Sometimes slightly cheaper, sometimes slightly more, depending on your electricity tariff and how well the system is set up. Don't switch from gas expecting to slash your bills.
  • Replacing oil: a typical saving of around £300–£900 a year.
  • Replacing LPG: around £500–£1,300 a year — LPG is expensive, so the gap is wider.
  • Replacing direct or storage electric heating: the biggest win, often £600–£1,500 a year.
If you're on mains gas, the reason to switch isn't your running costs — it's the £7,500 grant making the upfront cost manageable, plus comfort and carbon. We'd rather tell you that now than have you feel mis-sold later.

How they compare, point by point

Indicative comparison. Your figures depend on your home, tariff and usage.
Heat pumpGas boiler
Running cost vs gasRoughly neutralBaseline
Upfront costHigher, but £7,500 grant + 0% VATLower (a few thousand)
ComfortSteady, even warmth all dayQuick bursts of heat
CarbonMuch lower, falls further as the grid greensHigh — burns fossil gas
LifespanAround 15–20 yearsAround 10–15 years
Future-proofingAligned with where heating policy is headingFacing tightening rules over time

So — is a heat pump worth it?

If you're on oil, LPG or electric heating, the case is strong on running costs alone, before you even count the grant. If you're on mains gas, it's a more considered decision: you're buying comfort, much lower carbon and a system that fits where home heating is going, with the grant bringing the upfront cost within reach. What you're not buying is a dramatic bill cut.

The calculator above shows your numbers honestly — including the near-neutral running cost if you're on gas. No inflated savings.

Heat pump vs gas questions

Are heat pumps cheaper to run than gas boilers?

Usually not dramatically. Against mains gas, running costs are often close to neutral — sometimes a little less, sometimes a little more, depending on your tariff and setup. The honest case for switching from gas is the upfront grant, comfort and lower carbon, not a big cut to your bills. Against oil, LPG or direct electric, heat pumps do save money on running costs.

Is a heat pump worth it if I have mains gas?

It can be, but for different reasons than people expect. With the £7,500 grant the upfront cost is far lower than it used to be, you get steady even warmth, and you cut your home's carbon sharply. What you generally shouldn't expect is a large fall in running costs versus a modern gas boiler.

Do heat pumps keep a house as warm as gas?

Yes, when correctly sized and installed. Heat pumps deliver gentler, more constant heat rather than the quick blasts of a gas boiler, which most people find more comfortable once they adjust to running the system steadily.

What about the upfront cost compared to a new gas boiler?

A heat pump costs more upfront than a gas boiler even after the grant. The gap has narrowed a lot thanks to the £7,500 grant and 0% VAT, but a boiler swap is still cheaper on day one. The trade-off is carbon, comfort and future-proofing against tightening rules on fossil-fuel heating.