Heat Pump vs Gas Boiler Running Costs in Devon: The Real Numbers
"Heat pumps are cheaper to run" and "heat pumps cost a fortune in electricity" can't both be true, yet Devon homeowners hear both weekly. The real answer depends on three numbers: your electricity price, your gas (or oil) price, and your heat pump's efficiency. In 2026, electricity costs roughly 3.5 - 4 times more per kWh than gas on a standard tariff - but a well-installed heat pump in Devon delivers 3.5 - 4 kWh of heat for every 1 kWh of electricity it uses. Those two ratios nearly cancel out, which is why the running cost comparison is genuinely close on gas and decisively in the heat pump's favour against oil. And Devon matters here: the county's mild South West winters push heat pump efficiency higher than the UK average. Here are the actual numbers, worked through for a typical Devon home.
The Two Numbers That Decide Everything
A modern condensing gas boiler runs at about 85-92% efficiency in real conditions. Burn 1 kWh of gas, get around 0.9 kWh of heat. A heat pump doesn't burn anything - it moves heat from outside air into your home, so its "efficiency" is a multiplier. The seasonal average, called SCOP, is typically 3.5 - 4.0 for a properly designed system in Devon.
So the maths is simple. If electricity costs 25p per kWh and your heat pump has a SCOP of 3.7, your heat costs about 6.8p per kWh. If gas costs 6.5p per kWh and your boiler is 90% efficient, your heat costs about 7.2p per kWh. Close - with the heat pump slightly ahead, and pulling further ahead on a heat pump tariff.
The price cap figures that drive all of this are published quarterly by Ofgem's energy price cap page, and it's worth checking the current rates rather than relying on last year's headlines. If you'd rather have someone run the numbers for your actual house, Green Home Boilers & Heat Pumps does exactly that as part of a heat loss survey anywhere in Devon.
A Worked Example: Typical Devon Three-Bed
Take a three-bed semi in Exeter, Exmouth, or Cullompton using 10,000 kWh of heat per year - a reasonable figure for a reasonably insulated Devon home, slightly below the UK average because our winters are shorter and milder.
Gas boiler at 90% efficiency: you buy about 11,100 kWh of gas. At 6.5p per kWh plus roughly £115 of annual standing charge, that's around £835 a year.
Heat pump at SCOP 3.7: you buy about 2,700 kWh of electricity. At 25p per kWh, that's £675 a year - and you can drop the gas standing charge entirely if you disconnect gas, saving another £100+. On a dedicated heat pump tariff (several suppliers now offer electricity around 15-19p for heat pump households), the same heating year can cost £450 - £550. That's a £250 - £380 annual saving over gas, from the same house.
The tariff is half the battle
This is the bit most comparisons skip. On a standard tariff, gas vs heat pump is roughly a draw. On a heat pump tariff or smart time-of-use tariff, the heat pump wins clearly. If you install a heat pump and stay on a default standard variable tariff, you're leaving £150 - £250 a year on the table.
Why Devon Tilts the Numbers Towards Heat Pumps
SCOP figures aren't the same everywhere. A heat pump's efficiency drops as outdoor temperature falls, so the same unit achieves a better seasonal average in Devon than in Yorkshire. Devon's mean winter temperatures run 2-3°C warmer than the Midlands and the North, hard frost days are relatively few, and sub-zero nights - the conditions where a heat pump's efficiency dips towards 2.0 - 2.5 - are uncommon, especially near the coast around Exmouth and Plymouth.
In practice, that's worth something like 5-10% on your annual SCOP compared with colder regions, which feeds straight into the running cost. The Energy Saving Trust's heat pump advice puts typical savings against different fuels in independent terms, and their figures assume UK-average weather - Devon homes generally do a little better.
We've dug into the cold-weather question properly in our guide to heat pump performance in Devon winters, including what happens during the county's occasional cold snaps.
Off the Gas Grid? The Comparison Isn't Close
A large share of rural Devon has no mains gas at all - villages across Mid Devon, the fringes of Dartmoor, and much of the countryside between towns run on oil, LPG, or electric heating. For these homes the comparison changes completely.
Oil heat costs roughly 8-10p per kWh once boiler efficiency is factored in, and the price swings with global markets - Devon households on oil saw bills jump over 50% during the 2022 spike. LPG is worse still, often 11-13p per kWh of heat. Against those, a heat pump at 6-7p per kWh of heat isn't a marginal improvement; it's a 25-45% cut in heating costs, plus no more watching the tank gauge or timing a delivery before prices move.
Older rural properties still work
Devon's cob and stone cottages need a proper heat loss survey and sometimes bigger radiators, but they run happily on heat pumps when specified correctly. The efficiency argument holds - and these are precisely the oil-heated homes where the savings are biggest.
Don't Forget the Install Cost and the Grant
Running costs are only half the decision. A new gas boiler in Devon costs £2,500 - £4,500 installed. An air source heat pump costs £8,000 - £15,000 - but the Boiler Upgrade Scheme grant on gov.uk takes £7,500 off, so the real cost is £500 - £7,500. For plenty of Devon homes, the heat pump now costs about the same upfront as a decent boiler swap.
Combine that with £250 - £380 a year saved against gas (more against oil), a 15-20 year heat pump lifespan versus 10-15 for a boiler, and the whole-life numbers favour the heat pump in most Devon scenarios. Devon also has a solid supply of MCS-certified installers - the South West has been one of the stronger regions for heat pump uptake, so quotes are competitive.
When the Gas Boiler Still Wins
Honesty time: a heat pump isn't automatically cheaper for everyone. If your home is poorly insulated and you can't or won't improve it, the heat pump has to run at higher flow temperatures and the SCOP slides towards 2.5 - 3.0, at which point gas is cheaper to run. A badly designed installation does the same thing - undersized radiators forcing 55°C flow temperatures can wipe out the entire efficiency advantage.
The other case: a nearly new gas boiler. If yours is under 5-7 years old and reliable, replacing it early rarely stacks up financially. Run it, improve your insulation in the meantime, and switch when replacement time comes anyway. The grant plus a mild Devon climate will still be waiting - and your SCOP will be higher for the insulation work.
The Verdict for Devon Homeowners
On mains gas with a standard tariff: near enough a draw on running costs, with the heat pump edging it. On mains gas with a heat pump tariff: heat pump wins by £250 - £380 a year. On oil or LPG: heat pump wins comfortably, often by £400 - £800 a year. And in every case, Devon's mild winters mean you'll do better than the UK-average figures quoted in national guides.
The one non-negotiable is a proper heat loss survey and a competent installer. The gap between a SCOP of 3.0 and 4.0 is worth roughly £200 a year, every year - design quality is where that money lives.
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FAQ
Q: Is a heat pump cheaper to run than a gas boiler in Devon?
A: On a standard electricity tariff it's roughly a draw, with the heat pump slightly ahead. On a dedicated heat pump tariff, a typical Devon three-bed saves £250 - £380 a year versus gas. Devon's mild winters push heat pump efficiency above UK-average figures, which improves the comparison further.
Q: How much cheaper is a heat pump than oil heating in rural Devon?
A: Considerably. Oil heat costs roughly 8-10p per kWh; a heat pump in Devon delivers heat at around 6-7p per kWh. That's typically a 25-45% cut in heating costs - often £400 - £800 a year - which is why off-gas-grid Devon villages are among the strongest cases for switching.
Q: What efficiency (SCOP) should a heat pump achieve in Devon?
A: A properly designed system should achieve a SCOP of 3.5 - 4.0 in Devon - meaning 3.5 - 4 kWh of heat per kWh of electricity. The county's mild South West winters, with few hard frosts, mean Devon systems typically outperform the same equipment installed in colder UK regions by 5-10%.
Q: When is a gas boiler still the better choice in Devon?
A: If your home is poorly insulated and you won't improve it, or if your current boiler is under 5-7 years old and reliable. Poor insulation or a badly designed system pushes SCOP down towards 2.5 - 3.0, at which point gas is cheaper to run.
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