Solar PV with Heat Pump: Should You Install Both?
Yes for most well-insulated UK homes — solar PV + battery + air-source heat pump is one of the strongest decarbonisation packages available in 2026. Solar covers daytime base load and EV charging; battery covers heat-pump peak operation; heat pump replaces gas heating. The combination can cut a typical 4-bed UK home’s energy bills substantially — often by more than half — with the Octopus Cosy tariff and Predbat optimisation. Combined install costs are £18,000–£28,000 (PV plus heat pump) but BUS grant covers up to £7,500 of the heat pump.
UK heat pumps and solar PV used to be considered separately. In 2026 they’re increasingly specified together as a single decarbonisation package — solar generates daytime electricity, battery stores it for evening, heat pump consumes it. Get the sizing right and the household runs near-net-zero on electricity bills for the operational year.
Why the two work together
Heat pumps consume 2,500–4,000 kWh/year on a typical UK home replacing a gas boiler. That’s a meaningful load uplift on top of existing household consumption. Without solar PV, that load just imports from grid at peak rates. With solar PV (and battery storage), much of the heat-pump consumption is met from self-generated or off-peak-stored electricity. The combination shifts heating from gas to electricity AND keeps the electricity bill manageable.
Typical sizing for the combination
| Home | Solar PV | Battery | Heat pump |
|---|---|---|---|
| 3-bed semi, EPC C+ | 5–6kWp | 16kWh | 5–7kW air-source |
| 4-bed detached, EPC B+ | 6–8kWp | 16–24kWh | 7–9kW air-source |
| 5-bed older property, retrofitted to EPC C | 8–10kWp | 24–32kWh | 9–12kW air-source |
| Large detached, well-insulated | 10–14kWp | 32–48kWh | 12–16kW air-source |
The tariff that fits both
Octopus Cosy is built specifically for heat-pump households — three cheap windows per day for pre-heating, peak 4–7pm window the battery covers. See our Octopus Cosy article. Combined annual savings versus a baseline flat-tariff gas-boiler household are typically £2,000–£3,000/year on the full decarbonisation package.
Households comfortable with Home Assistant + Predbat sometimes prefer Octopus Agile for sharper savings, accepting the higher automation complexity. Agile + Predbat with heat pump beats Cosy by 5–10% net for households who tune it properly.
Indicative combined cost
| Component | Indicative cost |
|---|---|
| 5–6kWp solar + 16.1kWh battery (0% VAT) | £9,995–£11,800 |
| 7kW air-source heat pump install | £11,000–£14,000 ex-grant |
| BUS grant (Boiler Upgrade Scheme) | -£7,500 |
| Total combined investment | £15,500–£20,500 |
BUS grant on heat pumps
The Boiler Upgrade Scheme pays a flat £7,500 grant toward an air-source heat pump install (replacing a fossil-fuel boiler) and £7,500 for a ground-source heat pump. Apply through your MCS-certified heat-pump installer at the install stage. The grant materially improves the heat-pump payback maths.
Spectrum doesn’t install heat pumps directly but coordinates with specialist heat-pump installers across the East Midlands on combined PV-plus-heat-pump installs.
Combining solar with a heat pump?
We’ll design the solar and battery side, and coordinate with a heat-pump installer for the heating side. One coherent design, two MCS sign-offs.
Request a QuoteWhether to do them at the same time
Doing both together — pros:
- Single design optimisation across solar, battery, heat pump and consumer unit
- Avoids consumer-unit work twice
- Single G99 application covering combined load
- Cleaner tariff transition (move to Cosy/Agile once everything’s commissioned)
- Coordinated grant timing (BUS + 0% VAT)
Doing them separately — pros:
- Lower capital requirement at one time
- Solar payback can fund the heat-pump install years 3–4 later
- Heat-pump market may evolve (kit price, BUS amount) and you can wait
- Less disruption in one go
Most Spectrum customers who do both do them within 12 months of each other rather than simultaneously — lets the solar payback start while the heat-pump install is planned. The order doesn’t matter much; the combined benefit lands once both are running.
Sizing common pitfalls
- Under-sizing battery for heat-pump cold-evening load. Winter 4–7pm peak with heat pump running can pull 4–6kW. A 10kWh battery drains in 2 hours. 16–24kWh is usually the right answer for heat-pump homes.
- Over-sizing solar to ‘cover’ heat-pump. Summer surplus doesn’t store usefully into winter. Right-size for the year, not just the heat-pump load.
- Ignoring three-phase consideration. Combined load of solar export + heat pump + EV charging can push single-phase capacity. Three-phase upgrade may be required — check at site survey.
- Missing the BUS grant timing. The grant must be in place before heat-pump install commissioning. Apply early through your MCS heat-pump installer.
What changes for a 5-bed old-stock home
For larger, older or less-insulated homes, heat-pump load can run 5,000–8,000 kWh/year — double the well-insulated benchmark. Solar PV alone won’t cover that load; the heat-pump install needs to be paired with insulation improvements to bring annual consumption back into a manageable range. Otherwise the household just trades a high gas bill for a high electricity bill.
For these homes the package is solar + battery + heat pump + insulation upgrade — all four matter. Total investment lands at £30,000–£45,000 before incentives, with the £7,500 Boiler Upgrade Scheme grant on the heat pump and 0% VAT on the solar and battery taking a meaningful chunk off the headline figure.
FAQs
Does solar PV cover my heat pump electricity use?
Partially. A typical 5kWp solar array generates ~4,750 kWh/year. A heat pump consumes 2,500–4,000 kWh/year on a well-insulated home. Solar can cover a meaningful share of heat-pump consumption, particularly with battery storage. Winter coverage is lower than summer because of inverse seasonal solar/heating curves.
Can I run a heat pump on solar alone in winter?
No — UK winter solar generation is too low to cover heat-pump demand. December solar averages 10–15% of June output. Winter operation depends mainly on grid import via a time-of-use tariff (Cosy or Agile) and battery storage covering peak windows. Solar contributes meaningfully across the year, dominated by spring-summer-autumn months.
Should I install solar before or after a heat pump?
Order doesn’t matter materially. Many customers install solar first to start payback, then heat pump 1–3 years later when budget allows or the existing boiler nears end of life. Some do both together for design coherence. Both routes work; choose based on capital availability and existing heating system condition.
Does Spectrum install heat pumps?
No — Spectrum is MCS-certified for solar PV (NIC200223) but not heat pumps. We coordinate with specialist MCS heat-pump installers across the East Midlands for combined solar-plus-heat-pump installs. Customers get one coherent design and two MCS certifications — one per discipline.
How much does a solar + heat pump combination cost?
Typical combined cost in 2026 is around £15,000–£22,000 net of BUS grant for a 4-bed UK home: £9,995–£11,800 for solar + battery, plus £11,000–£14,000 for heat pump minus £7,500 BUS grant. Combined annual savings vs gas-boiler baseline are £2,000–£3,000/year.
Will solar void my heat-pump warranty?
No — heat pumps consume electricity from any source. The warranty is between you and the heat-pump manufacturer, independent of how the electricity arrives at the property. Some heat-pump installers value seeing solar in the install plan because it strengthens the home’s decarbonisation narrative.
What size heat pump for solar integration?
Heat pump sizing is determined by heat-loss calculation on the home — not by solar size. A well-insulated 4-bed semi typically needs 5–7kW heat output. Solar sizing follows separately based on roof and consumption. The two assets are independently sized but coordinated for combined load and tariff optimisation.
Related reading
- Octopus Cosy + Solar: maximising cheap heating slots
- Are solar panels worth it in 2026?
- Solar panel installation cost UK 2026
For the full Spectrum service overview see domestic solar overview.
Speak to Spectrum Energy Systems
MCS NIC200223. Solar PV + battery installs coordinated with specialist heat-pump installers across the East Midlands. Whole-home decarbonisation, one project plan.
Request a Quote