Heat Pump Running Costs vs a Gas Boiler in 2026/27
Comparing typical running costs of an air source heat pump against a gas boiler under the 2026/27 Ofgem price cap, and what drives the difference.
Why the Comparison Isn't a Simple Unit-Price Question
Comparing a heat pump to a gas boiler purely on the headline unit price of electricity versus gas is misleading, because the two systems convert fuel into heat with very different efficiency. A modern condensing gas boiler typically converts close to one unit of heat for each unit of gas burned. A well-installed air source heat pump, by contrast, moves heat from outside air into the home rather than generating it from combustion, and can typically deliver three to four units of heat for each unit of electricity consumed — a multiplier (often expressed as a Coefficient of Performance, or CoP) that can offset electricity's higher price per unit compared to gas.
What Actually Determines Whether You Save
| Factor | Effect on heat pump running cost |
|---|---|
| Home insulation quality | Better insulation reduces the heat demand the pump needs to meet, improving efficiency |
| Existing radiator/underfloor heating system | Systems designed for lower flow temperatures suit heat pumps better than standard high-temperature radiators |
| Gap between electricity and gas unit prices | A narrower gap favours the heat pump's efficiency multiplier more |
| Achieved Coefficient of Performance in practice | Real-world CoP can be lower than manufacturer figures in poorly-suited installations |
The theoretical efficiency advantage of a heat pump can be significantly eroded in a poorly insulated older property fitted with radiators sized for a gas boiler's higher output temperature — the heat pump may still function, but at a lower real-world efficiency than a well-matched installation, narrowing or even reversing the cost advantage over a gas boiler.
The Upfront Cost and Available Support
Installing a heat pump generally costs considerably more upfront than replacing a gas boiler like-for-like, which is a significant part of the overall decision alongside ongoing running costs. Government grant schemes have periodically offered support towards this upfront cost for households switching from a fossil fuel heating system, though the specific scheme, eligibility rules and grant amount change over time, so it's worth checking current gov.uk guidance for whatever scheme is available at the time of installation rather than relying on older figures.
Electricity Pricing for Heat Pump Use
Electricity consumed by a heat pump is billed under the same Ofgem price cap unit rate as any other household electricity use, unless you're specifically on a tariff designed around heat pump or off-peak usage. This means the running-cost comparison against gas depends on the standard electricity and gas unit rates in place at the time, both of which move with each quarterly Ofgem price cap update, so a comparison done at one point in time may shift as the relative prices of gas and electricity change.
Working Out Whether a Switch Makes Sense for You
- Assess your home's insulation standard and whether upgrades would be needed alongside a heat pump
- Check whether your existing radiators (or underfloor heating) suit lower flow temperatures, or would need upgrading
- Compare current gas and electricity unit rates against a realistic expected Coefficient of Performance
- Check current grant scheme availability to offset the upfront installation cost
Use the electricity cost and energy bill calculators below to compare estimated running costs between a heat pump and a gas boiler at current unit rates.
Frequently asked questions
Why can a heat pump be cheaper to run than a gas boiler despite electricity costing more per unit than gas?
A heat pump doesn't generate heat by burning fuel — it moves existing heat from the outside air (or ground) into your home, and typically produces around three to four units of heat for every one unit of electricity consumed. This efficiency multiplier can offset the higher per-unit price of electricity compared to gas, though the actual outcome depends on the specific efficiency achieved and the price gap between electricity and gas unit rates at the time.
Does a heat pump work well in an older, poorly insulated UK home?
Heat pumps generally perform best in well-insulated homes with a heating system (larger radiators or underfloor heating) designed to work at the lower flow temperatures heat pumps typically produce. In a poorly insulated older property with a standard radiator system sized for a gas boiler's higher flow temperature, a heat pump can still work but may run less efficiently and cost more than expected, making insulation improvements a worthwhile consideration alongside the switch.
Are there grants available to reduce the upfront cost of installing a heat pump?
Government grant schemes have periodically offered a contribution towards the upfront cost of installing an air source heat pump to replace a fossil fuel heating system, though the specific scheme, eligibility criteria and grant amount available change over time, so checking current gov.uk guidance for the scheme in place is worthwhile before budgeting for an installation.
How is the electricity used by a heat pump priced under the Ofgem cap?
Electricity used to run a heat pump is billed at the same standard electricity unit rate under the Ofgem price cap as any other household electricity use, unless you're on a specific tariff offering a different rate for heat pump usage — there's no automatic separate, cheaper electricity rate simply because the usage is for heating via a heat pump.
Try the calculators
Related reading
Switching Energy Supplier in 2026/27 — Is It Worth It Under the Price Cap?
Whether switching energy supplier still saves money now most default tariffs sit near the Ofgem price cap, and how to compare fixed deals for 2026/27.
Challenging Your Council Tax Band in 2026/27 — What Actually Works
How UK council tax bands were originally set, when a formal challenge is worth pursuing, and the risk of your band going up in 2026/27.
Disabled Facilities Grant and Home Adaptations: Tax and Council Tax Effects in 2026/27
Is a Disabled Facilities Grant taxable? Does adapting your home for disability change your Council Tax band? The financial side effects of home adaptations explained for 2026/27.