Solar Panels with a Heat Pump: The UK Homeowner Guide
Installing solar PV alongside a heat pump is the single most effective way for a UK homeowner to cut energy bills and carbon emissions. This guide covers system sizing, grants, costs and install order, so you get the pairing right.
Quick Answer
A solar + heat pump combo in a typical 3-bed UK home costs £13,500–£17,500 after the £7,500 Boiler Upgrade Scheme grant and 0% VAT on solar. It saves £1,500–£2,000 per year versus a gas boiler plus grid electricity. The heat pump covers heating and hot water, and solar PV offsets the extra electricity demand. Payback is typically 8–12 years on the combined system.
Last updated April 2026
Why Pair Solar Panels with a Heat Pump?
A heat pump is an electric heating system, typically 3–4× more efficient than a gas boiler, but it shifts your home's energy consumption from gas to electricity. Gas currently costs around 6p/kWh, electricity 28p/kWh. So moving from gas to electric heating cuts kWh demand but not necessarily cash cost, unless you generate your own electricity.
What is COP (Coefficient of Performance)?
COP measures how much heat a heat pump produces per unit of electricity consumed. A modern air source heat pump installed in a well-insulated UK home typically runs at a seasonal COP (SCOP) of 3.0–4.0, meaning it delivers 3–4 kWh of heat for every 1 kWh of electricity. A gas boiler is capped at a COP of about 0.9 (9% losses to flue gas). Higher SCOP = lower running cost, which is why MCS installers always target a SCOP of at least 2.8 for BUS grant eligibility.
Solar PV closes that gap. In a typical UK 3-bed home:
- Heat pump alone: cuts heating emissions ~70%, but total bills may be similar to gas
- Solar alone: offsets daytime electricity use, saves £700–£1,100/year on a 4.4 kWp system
- Combined: solar generates the electricity your heat pump consumes, cutting total energy bills by £1,500–£2,000/year and emissions by 80–90%
The pairing works especially well because heat pumps have high daytime consumption (preheating the home and hot water tank) , which lines up with peak solar generation. With a battery added, self-consumption of solar jumps to 80%+ and the combined system approaches grid independence for 6–8 months of the year.
How to Size a Combined Solar + Heat Pump System
A heat pump typically doubles a UK home's electricity consumption because it now provides heating and hot water that used to come from gas. So the right solar array is larger than for a gas-heated home. Aim to cover 40–60% of combined annual demand to keep payback attractive.
| House type | Heat demand | Heat pump size | Recommended solar | Combined cost (after grants) |
|---|---|---|---|---|
| 2-bed flat / small terrace | 6,000 kWh | 4 kW ASHP | 3.5 kWp (8 panels) | £11,000–£14,000 |
| 3-bed semi (typical UK home) | 10,000 kWh | 5–6 kW ASHP | 4.4–5.3 kWp (10–12 panels) | £13,500–£17,500 |
| 4-bed detached | 14,000 kWh | 8 kW ASHP | 5.3–7 kWp (12–16 panels) | £16,000–£21,000 |
| 5-bed / large detached | 18,000+ kWh | 10–12 kW ASHP | 7–9 kWp (16–20 panels) | £20,000–£26,000 |
Costs include 0% VAT on solar and the £7,500 Boiler Upgrade Scheme grant on the heat pump. Assumes typical UK electricity demand patterns and a 55%/45% summer/winter solar generation split. Actual sizing depends on insulation, heat loss calculation, and roof space.
Grant Stacking: BUS + 0% VAT
You can claim both schemes on a single combined installation. They apply to different equipment so there is no double-funding restriction.
Heat pump: £7,500 BUS
The Boiler Upgrade Scheme (BUS) pays £7,500 towards an air source heat pump. Eligible homes must have a valid EPC with no outstanding insulation recommendations. Your installer applies on your behalf and discounts the invoice.
Heat pump guide →Solar: 0% VAT
Residential solar PV and battery storage installations in the UK attract 0% VAT until March 2027, saving you 20% on the full system cost. This applies to supply-and-install contracts from VAT-registered installers.
Solar grants guide →Example: 3-bed semi, combined install
Heat pump £14,000 − £7,500 BUS = £6,500. Solar 4.4 kWp at 0% VAT = £7,700 (would be £9,240 at 20% VAT). Total after grants: £14,200. About the cost of a kitchen refit, for a 25-year asset.
Which Should You Install First?
If you're doing both at once, have the installer plan them together. Ideally use the same installer, or two installers coordinating. If you're doing them in stages, the order depends on what you already have:
Existing gas boiler working fine → install solar first
Solar pays back faster (6–8 years vs 10–15 for a heat pump). Install solar now, save cash, then replace the boiler with a heat pump when it dies. Size the solar array for future heat pump demand (add 30–50% capacity) so you don't have to top up later.
Boiler is failing → install heat pump first
Don't replace a dying gas boiler with another gas boiler if you plan to go electric, as you'd waste 10–15 years of heat pump efficiency. Install the heat pump now with the £7,500 BUS, then add solar within 12 months so your grant-funded heat pump runs on your own electricity.
Building new or doing a deep retrofit → both at once
Single scaffolding, single project manager, one disruption. You can also install a hybrid inverter sized for future battery, and DC-couple a battery later. Aim for MCS-certified installers on both technologies.
Should You Add a Battery Too?
Yes. A 5–10 kWh battery transforms the economics of a solar + heat pump combo. Heat pumps run hardest in winter when solar generation is lowest, so during heating season the match between solar and demand is poor. A battery paired with an off-peak tariff (e.g. Octopus Go at 7p/kWh overnight) lets you charge cheaply, use stored power through the day, and still capture excess summer solar.
Typical battery add-on: £3,500–£6,500 at 0% VAT. Combined with smart tariff switching, a 10 kWh battery can shave another £400–£700/year off the combined system's running costs.
For details, see our solar battery storage guide, size a combined system with the solar calculator, and if you need to spread the cost, see solar financing options.
Common Pitfalls to Avoid
- Undersized solar array. Sizing for pre-heat pump electricity demand means you'll only cover 20–30% of combined use. Always size for post-heat-pump demand.
- Oversized heat pump. Many installers oversize to avoid call-backs. An oversized heat pump cycles too often, runs less efficiently, and costs more than necessary. Insist on a proper MCS heat loss calculation (not a rule-of-thumb sizing).
- Missing the EPC condition. BUS requires no outstanding insulation recommendations on your EPC. Upgrade insulation first (or at least close out EPC actions) before applying.
- Poor installer coordination. The solar installer may wire the inverter where the heat pump installer wants to put the outdoor unit. Or the DNO application for one can clash with the other. Use a single-project installer or brief both teams on the full plan.
- Leaving the old radiators in place. Heat pumps run at lower flow temperatures (40–50 °C vs 70 °C for gas). Undersized radiators will leave rooms cold. A good MCS heat pump installer specifies radiator upgrades where needed.
Frequently Asked Questions
Can I claim both the £7,500 BUS grant and 0% VAT on solar?
Yes. The Boiler Upgrade Scheme applies to the heat pump only, and 0% VAT applies to the solar PV and battery only. The two schemes don't overlap, so both apply to a combined installation.
Will solar panels fully power my heat pump?
In summer and shoulder seasons yes, a correctly sized solar array can cover 70–100% of heat pump demand. In winter, solar generation drops to 10–20% of summer peaks while heat demand is highest, so you'll still draw from the grid. A battery and smart tariff fill most of the gap.
How much does a solar + heat pump combo cost in the UK?
For a typical 3-bed UK home, budget £13,500–£17,500 after grants: £6,500 for a heat pump (after £7,500 BUS) and £7,000–£11,000 for a 4.4–5.3 kWp solar array at 0% VAT. Larger homes cost £20,000–£26,000 combined.
How long is the payback on a combined system?
Typically 8–12 years on the full combined system versus continuing with a gas boiler and grid electricity. Solar alone pays back in 6–8 years; the heat pump component is slower (10–15 years) because it mainly replaces gas, which is cheaper per kWh than electricity. The combination is better than either alone.
Do I need a special inverter for the combo?
No, a standard hybrid inverter works. A heat pump draws AC from your home circuit just like any other appliance. The only considerations are: (1) size the solar array for post-heat-pump demand, (2) consider a battery-ready hybrid inverter (Huawei, GivEnergy, Solis) to add storage later, and (3) confirm your DNO connection supports both loads.
Do both need to be installed by MCS-certified installers?
Yes. The Boiler Upgrade Scheme requires an MCS-certified heat pump installer. 0% VAT on solar and the Smart Export Guarantee require MCS-certified solar installation. Using uncertified installers invalidates both financial benefits.
What about gas hybrid heat pumps?
A hybrid heat pump pairs a heat pump with a gas boiler for peak demand. It's a valid transitional option but doesn't qualify for the £7,500 BUS grant in most cases. For a new installation with solar, a standalone air source heat pump with a battery is usually the better economics.
Related Guides
Heat Pumps
Air source & ground source heat pumps: costs, BUS grant up to £7,500.
Solar vs Heat Pumps
Comparing two leading renewable technologies.
Solar Incentives
0% VAT, Smart Export Guarantee, ECO4, and business capital allowances.
Battery Storage
Solar battery costs, sizing, popular models, and payback analysis.
Sources
- Ofgem: Boiler Upgrade Scheme (BUS)
- HMRC: 0% VAT on energy-saving materials
- MCS: Certified installer directory
- DESNZ: UK Housing Energy Fact File 2024
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He fact-checks all content against official MCS and Ofgem data and maintains relationships with MCS-certified installers across the UK.
Ready for a Combined Quote?
Get free, no-obligation quotes from MCS-certified installers who handle both solar and heat pumps. One quote, one project manager, one grant application.