Air Source Heat Pump and Solar Panels: The Perfect Combo

Combining a heat pump with solar panels could cut your heating bills by £500–£820 per year and reduce your home’s carbon emissions by up to 90%.

This guide breaks down the real savings, honest costs, and exactly how the two systems work together in a typical UK home — so you can decide if the combination is worth it for you.

A heat pump uses electricity to heat your home. Solar panels generate free electricity from sunlight. Put them together and you have a heating system that is partially powered by energy you produce yourself — reducing your bills, your carbon footprint, and your dependence on the grid.

It sounds like a perfect match, and in many ways it is. But the relationship between solar panels and heat pumps is more nuanced than the marketing suggests. The timing mismatch between solar generation (mostly summer daytime) and heat pump demand (mostly winter evenings) means the real-world savings are less dramatic than the headline figures — unless you add a battery or use smart controls.

How Solar Panels and Heat Pumps Work Together

The basic principle is simple: solar panels generate electricity, and your heat pump uses electricity. When the solar panels are generating, the heat pump can run on free solar power instead of drawing from the grid.

In practice, this works in three ways:

Direct Self-Consumption

When your solar panels are generating electricity and your heat pump is running simultaneously, the heat pump uses the solar electricity directly. This is the most valuable scenario because you avoid buying electricity from the grid entirely — saving the full unit rate (currently around 24.5p/kWh).

Grid Export and Import

When your solar panels generate more than you are using, the surplus is exported to the grid. Under the Smart Export Guarantee (SEG), you receive a payment for exported electricity — typically 4-15p/kWh. When the heat pump runs and the solar panels are not generating, you import from the grid at the standard rate.

Battery Storage

A home battery stores excess solar electricity for use later — for example, storing daytime solar generation to power the heat pump in the evening. This significantly increases the proportion of heat pump electricity that comes from solar, but the battery itself costs £3,000–£8,000.

The Timing Mismatch: The Honest Truth

Here is the challenge that marketing materials tend to gloss over: your heat pump needs the most electricity in winter, when solar panels generate the least.

Over a full year, without a battery, solar panels typically offset 20–35% of a heat pump's total electricity consumption. With a battery, this can rise to 40–55%.

Real-World Savings: The Numbers

Let us work through a realistic example for a 3-bedroom semi-detached house with a 4kW solar panel system and an 8kW air source heat pump.

Without Solar Panels

• Heat pump annual electricity consumption: 4,000 kWh
• Electricity cost at 24.5p/kWh: £980 per year

With Solar Panels (No Battery)

• Solar self-consumption by heat pump: ~1,000 kWh (25% of HP demand)
• Grid electricity for heat pump: 3,000 kWh × 24.5p = £735
• Saving on heat pump costs: £245 per year
• Additional solar savings on household electricity: ~£200 per year
• SEG export income: ~£80–£150 per year
• Total annual benefit: £525–£595

With Solar Panels and Battery (5kWh)

• Solar self-consumption by heat pump: ~1,800 kWh (45% of HP demand)
• Grid electricity for heat pump: 2,200 kWh × 24.5p = £539
• Saving on heat pump costs: £441 per year
• Additional solar savings on household electricity: ~£300 per year
• SEG export income: ~£40–£80 per year
• Total annual benefit: £781–£821

Combined Installation Costs

For comprehensive solar panel pricing, visit Home Solar Guide, our sister site dedicated to solar energy in the UK.

Smart Controls: Making the Combination Work Harder

The key to maximising the benefit of solar panels with a heat pump is smart timing — running the heat pump when solar generation is available.

Solar Diverters

A solar diverter detects surplus solar electricity and uses it to heat your hot water cylinder via an immersion heater. Simple and cheap (£200–£500).

Smart Heat Pump Controls

Some controllers pre-heat the house or boost the hot water cylinder when solar generation is high — using your home's thermal mass as a heat battery.

Time-of-Use Tariffs

Tariffs like Octopus Cosy offer cheaper rates at certain times. Combined with solar and a battery, you can avoid expensive peak rates entirely.

Home Energy Management Systems

Products from myenergi and GivEnergy coordinate solar panels, batteries, heat pumps, and EV chargers automatically (£200–£1,000).

Grants for the Combined System

The grant landscape for combining heat pumps and solar:

• BUS grant (£7,500): available for the heat pump. Solar panels do not affect eligibility.
• 0% VAT on solar panels: residential solar installations are currently VAT-free.
• Smart Export Guarantee: ongoing payments for electricity you export — typically 4–15p/kWh.
• ECO4 scheme: if you are on certain benefits, you may qualify for subsidised measures.

The individual incentives stack — claim the BUS grant for the heat pump AND benefit from 0% VAT on solar in the same project. Full details in our grants guide.

Is It Better to Install Both at the Same Time?

If you can afford it, yes. Installing the heat pump and solar panels together offers:

• Shared scaffolding — saves on hire costs
• Electrical work coordination — both connect to your consumer unit
• System integration — configured to work together optimally
• Single disruption period — not two separate projects

However, installing them sequentially is perfectly fine. Either order works.

Environmental Impact

Combining a heat pump with solar panels creates one of the lowest-carbon heating systems possible for a UK home.

As the UK grid continues to decarbonise (over 50% renewable), heat pump carbon emissions fall further. By 2030, a heat pump with solar will produce negligible emissions.

Check suitability with our suitability checker, or estimate costs with our calculator.

Frequently Asked Questions

Can solar panels fully power a heat pump?

In summer, yes — solar panels can cover the heat pump's hot water needs with surplus to spare. In winter, solar covers only 10–15%. Over a full year, solar typically offsets 20–35% without a battery, or 40–55% with a battery.

How many solar panels do I need to run a heat pump?

A 4kW system (roughly 10 panels) is a good starting point. Larger systems (5–6kW, 12–15 panels) offset more electricity but hit diminishing returns without a battery.

Do I need a battery to combine solar with a heat pump?

No, but a battery increases the proportion of heat pump electricity from solar — from 20–35% to 40–55%. The battery adds £3,000–£8,000.

Can I get grants for both solar panels and a heat pump?

Yes. The BUS grant (£7,500) covers the heat pump. Solar panels get 0% VAT. These stack.

Will solar panels affect my BUS grant eligibility?

No. Solar panels do not affect BUS grant eligibility in any way.

Is it worth adding solar panels if I already have a heat pump?

Yes, especially with a south-facing roof. Solar panels pay for themselves in 6–9 years. Having a heat pump increases the value of self-generated electricity. Visit Home Solar Guide for detailed solar information.