Option A
Heat pump
A heat pump uses electricity to move heat from outside air or the ground into your home. It works best at lower flow temperatures in well-insulated properties.
Heat pump vs gas boiler: is a heat pump worth it?
Updated June 2026 9 min read
Quick verdict
A heat pump can work well in a well-insulated home with suitable radiators or underfloor heating, especially if grant support reduces the upfront cost. A gas boiler is usually cheaper and simpler to install, particularly as a quick replacement in an older or less efficient home.
Option B
Gas boiler
A gas boiler burns natural gas to heat water for radiators and hot water. It is cheaper to install and widely supported, but uses fossil fuel.
Side-by-side comparison
Heat pumps are highly efficient but depend heavily on the home. Gas boilers are familiar, cheaper to install and work with most existing heating systems. Before switching, check insulation, radiator sizes, hot water storage and total installation cost.
Installation cost
Heat pump
£8,000 to £15,000 before support
Gas boiler
£1,500 to £3,500 typicalBetter
Running cost
Heat pump
Depends heavily on efficiency and tariff
Gas boiler
Often lower in many current homes
Efficiency
Heat pump
Very high when specified wellBetter
Gas boiler
High for modern condensing boilers
Carbon emissions
Heat pump
LowerBetter
Gas boiler
Higher
Existing radiators
Heat pump
May need upgrades
Gas boiler
Usually worksBetter
Hot water cylinder
Heat pump
Usually needed
Gas boiler
Not always with combi boilerBetter
Best for
Heat pump
Efficient homes and long-term upgrades
Gas boiler
Low-cost direct replacement
| Compare | Heat pump | Gas boiler |
|---|---|---|
| Installation cost | £8,000 to £15,000 before support | £1,500 to £3,500 typicalBetter |
| Running cost | Depends heavily on efficiency and tariff | Often lower in many current homes |
| Efficiency | Very high when specified wellBetter | High for modern condensing boilers |
| Carbon emissions | LowerBetter | Higher |
| Existing radiators | May need upgrades | Usually worksBetter |
| Hot water cylinder | Usually needed | Not always with combi boilerBetter |
| Best for | Efficient homes and long-term upgrades | Low-cost direct replacement |
Pros and cons
Heat pump pros and cons
Pros
- ✓Lower carbon heating
- ✓Very efficient in suitable homes
- ✓Grant support may reduce upfront cost
- ✓Long-term alternative to fossil-fuel heating
Cons
- -High upfront cost
- -May need insulation or radiator upgrades
- -Needs space for an outside unit and usually a cylinder
- -Requires different heating habits
Gas boiler pros and cons
Pros
- ✓Lower installation cost
- ✓Works with most existing systems
- ✓Familiar and widely serviced
- ✓Quick replacement if a boiler fails
Cons
- -Uses fossil fuel
- -Exposed to gas price changes
- -Shorter typical lifespan
- -Less aligned with long-term decarbonisation policy
Cost examples
Modern insulated home
A heat pump is more likely to perform well where insulation, emitters and hot water storage are already suitable.
- Likely fit
- Heat pump
Average older semi
A gas boiler may be cheaper unless insulation and radiator upgrades are part of the plan.
- Likely fit
- Gas boiler now
Carbon-first upgrade
If reducing emissions is a priority, a heat pump can be attractive even where the payback is not purely financial.
- Key reason
- Carbon
When to choose Heat pump
- ›Your home is well insulated
- ›You have space for a cylinder and outdoor unit
- ›You qualify for relevant grant support
- ›You plan to stay long term
- ›Lower carbon heating is a priority
When to choose Gas boiler
- ›You need a quick affordable replacement
- ›Your home needs insulation upgrades first
- ›You have no space for a cylinder or outdoor unit
- ›You may move soon
- ›Your budget cannot absorb the heat pump project cost
Calculator
Calculate your own figures
Use the calculator below for a personal estimate, or open the full tool for the complete calculator page.
FAQs
Are heat pumps cheaper to run than gas boilers?
Not always. Heat pumps are more efficient, but electricity usually costs more per unit than gas. The result depends on system efficiency, insulation and tariff.
What grant support is available for heat pumps?
Government support has been available through schemes such as the Boiler Upgrade Scheme in England and Wales. Eligibility and amounts can change, so check current rules before budgeting.
Do heat pumps work in cold weather?
Yes. Modern systems can work in UK winter temperatures, but they must be correctly sized and installed for the home.
Can a heat pump replace a combi boiler?
Not like-for-like in most homes. Heat pumps usually need a hot water cylinder, so storage space is an important practical check.
Do I need new radiators for a heat pump?
Possibly. Heat pumps often run at lower temperatures, so some homes need larger radiators or other upgrades to heat rooms effectively.
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