With energy prices and climate targets in the headlines, more homeowners are asking: “Should I stick with a gas boiler or switch to a heat pump?”
The answer depends on your home, budget, and how long you plan to stay – but there are clear patterns in upfront cost, running cost and EPC impact that can help you decide.
This guide compares:
- Typical installation costs: boiler vs air source heat pump
- Running‑cost considerations under different tariffs
- Grants and funding that change the equation
- Which option usually makes sense for different property types
For detailed breakdowns of each option separately, see New Boiler Cost UK (2025): Complete Price Guide and Air Source Heat Pump Costs UK.
1. Upfront cost: boiler vs heat pump
Broadly:
- Gas boiler replacement (combi ↔ combi): often £2,000–£3,000+ installed.
- System/regular boiler setups: often £2,500–£4,000+ depending on cylinder and complexity.
- Air source heat pump (including system upgrades): often £7,000–£12,000+ before grants, with several thousand pounds potentially covered by the Boiler Upgrade Scheme for eligible homes.
Heat pumps usually cost more upfront because:
- The unit itself is more expensive.
- Systems may need radiator or pipework upgrades and new controls.
- Proper design and commissioning take time.
Boilers are cheaper to install, especially in like‑for‑like replacements.
2. Running costs and efficiency
Boilers and heat pumps differ in how they use energy:
- A modern gas boiler is typically around 90%+ efficient – most of the gas burned becomes useful heat.
- A well‑installed air source heat pump can achieve a seasonal coefficient of performance (SCOP) around 2.5–3.5, meaning 2.5–3.5 units of heat for each unit of electricity, depending on system design and usage.
Whether a heat pump is cheaper to run than a boiler depends largely on:
- The relative prices of gas and electricity.
- The heat pump’s efficiency in your home.
- Your heating pattern and thermostat settings.
In a well‑insulated home with a good tariff and smart controls, heat pumps can compete strongly on running costs – and they’re far better on carbon emissions. In a draughty home without fabric upgrades, they may need to work harder, eroding some of the benefit.
3. EPC and carbon impact
From an EPC perspective:
- Efficient gas boilers can improve your EPC by increasing heating efficiency, especially when replacing very old models. See Does a New Boiler Improve Your EPC Rating?.
- Heat pumps are typically treated even more favourably, because they deliver multiple units of heat per unit of electricity and significantly reduce carbon emissions.
For carbon‑reduction goals and future‑proofing, heat pumps generally come out ahead – provided the home is heat‑pump‑ready (good insulation, correctly sized radiators, etc.).
4. Grants and funding
This is where the picture changes significantly:
- Boiler grants: Targeted mainly at low‑income or vulnerable households in inefficient homes. See Boiler Grants UK 2025.
- Heat pump grants: The Boiler Upgrade Scheme offers substantial support towards low‑carbon systems for eligible owner‑occupiers.
- Broader home energy grants can support insulation, heating controls and other measures that benefit both options – see Home Energy Grants UK 2025 (/insights/home-energy-grants-uk).
If you qualify for strong heat‑pump support and your home is suitable, the net cost gap between boiler and heat pump may be smaller than it first appears.
5. Which is better for which types of home?
Better suited to a boiler (for now)
- Homes on mains gas with limited scope for fabric upgrades in the short term.
- Properties where radiators and pipework are sized for higher flow temperatures, making heat pumps harder to integrate immediately.
- Situations where budget is tight and a like‑for‑like swap is the only realistic option.
Better suited to a heat pump
- Well‑insulated homes (especially newer builds or deeply retrofitted properties).
- Homes planning or already having underfloor heating or oversized radiators.
- Owners with long‑term plans who prioritise carbon reduction and resilience to future gas‑price volatility.
Mixed cases
Many homes fall somewhere in between, where the best path might be:
- Improve fabric and controls first (loft, walls, draughts, smart thermostats).
- Fit a modern boiler now if the existing one is at end‑of‑life.
- Plan for a heat‑pump‑ready retrofit over the next 5–10 years.
6. Comfort, noise and practicalities
Boilers
- Familiar on/off behaviour with quick response on radiators.
- Compact indoor unit; no external fan.
- Needs flue and safe gas supply; may require future changes as gas policy evolves.
Heat pumps
- Run for longer at lower flow temperatures, giving a more consistent background warmth.
- External unit with fan noise, usually modest but needs thoughtful placement.
- Often need larger radiators or underfloor loops and careful commissioning to perform well.
Both systems can provide good comfort when designed correctly; poor design on either side leads to complaints.
7. Landlords: boiler or heat pump?
For landlords, the choice is tied to EPC compliance, tenant appeal and capital planning:
- A modern boiler can help move properties towards E or D and potentially C, especially when combined with insulation.
- Heat pumps may become a stronger option over time as standards tighten and grant schemes evolve – particularly in well‑insulated, modern rentals.
Start by understanding your obligations and timelines via EPC Rules for Landlords in 2025–2030, then use:
to see where heating upgrades (boiler or heat pump) fit into a wider plan.
8. How to decide what’s right for you
To make a grounded choice:
- Check your EPC using our EPC checker and review the recommendations.
- Improve insulation and draught proofing – these benefit both boilers and heat pumps.
- Use New Boiler Cost UK (2025): Complete Price Guide and Air Source Heat Pump Costs UK to benchmark realistic prices.
- Investigate grants you might qualify for – both for boilers and low‑carbon systems.
- Consider your time horizon: are you planning to stay for 2, 5 or 15+ years?
In some cases, the best answer is staged:
- Short term: replace a failing boiler with a modern unit to restore reliability and improve efficiency.
- Medium term: continue to upgrade fabric and controls.
- Long term: review the case for a heat pump when the home and policy environment are ready.
9. FAQs
Is a heat pump always cheaper to run than a gas boiler?
Not always. It depends on energy prices, the heat pump’s efficiency in your particular property, and how you use heating and hot water. In well‑insulated homes with good design and tariffs, heat pumps can be competitive or cheaper; in leaky homes without fabric upgrades, they may struggle.
Will a heat pump improve my EPC more than a boiler?
In many cases, yes – EPC calculations tend to reward low‑carbon heating systems with high seasonal efficiency. However, full EPC impact depends on the whole home (insulation, windows, controls), not just the heat source.
What if my boiler is old but my house isn’t ready for a heat pump?
You may be best doing a two‑stage upgrade: install a modern boiler now for reliability and modest EPC gains, while planning fabric improvements so a future heat pump can work efficiently.
Where can I learn more about improving my EPC?
Start with our improvement hub, 27 Ways to Improve Your EPC Rating, and the band‑specific guides How to Improve EPC from E to D and How to Improve EPC from D to C. They’ll help you see where boilers and heat pumps sit in the bigger picture.