The bit nobody explains properly: why electricity costs more than gas
Worth saying upfront: heat pumps also cut direct fossil fuel burning in your home. That matters on its own, regardless of how the sums below work out. This page focuses on the cost side, because that’s the part most guides skip past.
A heat pump runs on electricity. A boiler runs on gas. And right now, electricity costs roughly four times more per unit than gas.
That sounds like it should rule heat pumps out completely. It doesn’t. Heat pumps are so efficient — they move heat rather than burning fuel to create it — that they can still work out cheaper to run overall, especially in a well-insulated home. But the sums are tighter than they should be. Here’s why:
A big chunk of the policy costs of moving Britain to cleaner energy has historically been loaded onto electricity bills, not gas ones. Think funding for renewables, or support schemes for low-income households. So every time you use electricity, you’re also paying towards costs that have nothing to do with your own usage. Gas, meanwhile, carries much less of that weight, even though it’s the fuel we’re trying to move away from.
In plain terms: the pricing is backwards for what the country’s trying to achieve, and the government knows it.
What it actually costs right now (the honest numbers)
Buying and installing:
Typically £7,000–£13,000 before any grant, depending on your home and system type.
The grant:
The Boiler Upgrade Scheme grant is £7,500 for an air or ground source heat pump, or £9,000 if you’re replacing an oil or LPG system. Your installer claims this on your behalf and takes it off your price — you don’t apply for it yourself or receive cash.
Running costs:
This is the honest bit: in a well-insulated home, a heat pump usually costs similar to or less than a gas boiler to run. That’s because it’s so efficient. In a poorly insulated, older home, it can end up costing more. The pump has to work harder, and the tighter electricity-vs-gas pricing bites harder. This is genuinely the honest state of the arithmetic for poorly insulated homes on standard tariffs — for better-insulated homes, the picture is already brighter.
What this means for you practically: if it fully happens, heat pump running costs get noticeably better, possibly quite quickly. If you’re on the fence, it’s worth knowing this is actively being discussed — not a settled “no.”
What it’s actually like day to day (the self-adopter bit)
A few honest, non-salesy things people notice after switching:
It runs differently to a boiler. Heat pumps work best left on low and steady, rather than blasted on and off like a gas boiler. It takes a bit of adjusting to.
Radiators feel less hot to the touch, but the room still warms up. This surprises people at first — it’s not a fault, it’s just how the system’s designed to run efficiently.
Hot water can take longer to heat, depending on the system — worth asking your installer about this directly if you have a big household.
It’s quieter than people expect, but not silent. There’s a low outdoor unit hum, similar to an air conditioning unit.
None of this is a downside dressed up — it’s just different, and most people adjust within a few weeks.
So, is it worth it?
Probably worth it if:
Your home is reasonably well insulated. Or you’re planning insulation work anyway.
You’re replacing an old boiler regardless. An inefficient one, due for replacement regardless of a heat pump.
The upfront cost isn’t a stretch. Even after the grant, you’re not on a tight budget for it.
Probably worth waiting if:
Poor insulation, no plan to fix it first. That’s when heat pumps struggle most.
Relying entirely on running-cost savings. That’s a harder case to make while the electricity-vs-gas pricing gap is still only partly resolved.
Your current boiler still has years left. There’s less urgency to switch right now.
Frequently asked questions
Is the government fixing the electricity-vs-gas price gap?
Where can it go, and what does distance cost?
Summary
The short version
Electricity costs 4x more per unit than gas
That’s the real reason the running-cost sums feel tight — not the heat pump itself.
Rebalancing is coming, but slowly
£7k–£13k installed, £7.5k–£9k grant
The Boiler Upgrade Scheme grant is claimed by your installer and taken off the price directly.
Runs steady, not blasted
Lower, longer heat instead of short hot bursts — the biggest habit change, not a fault.
Insulation decides the answer
Well-insulated homes usually come out ahead on running costs. Poorly insulated ones often don’t — yet.
Just Ask: Heatpump
Just Ask: Heatpump is an independent companion to Visit a Heat Pump and Get a Heat Pump. Built from real installation experience to give honest, practical guidance before you commit.
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