Last Updated on October 20, 2026
A heat pump with solar panels can be an effective combination for reducing household energy bills. However, the two technologies have one important challenge: solar panels generate most of their electricity during the warmer months, while heat pumps use the most electricity in winter.
A typical 4 kWp solar panel system in central England could generate approximately 3,873 kWh annually, compared with around 2,850 kWh of electricity used by a heat pump in our example. Although the annual figures suggest solar panels could cover the heat pump’s demand, the seasonal difference means you will still need electricity from the grid.
We have compared solar generation and heat pump consumption month by month, using European Commission solar data, UK energy consumption figures and electricity tariffs available in October 2026.
We also look at whether battery storage is worthwhile, how much an off-peak tariff could save and what financial support is available when installing both systems.
Quick answer: Yes, solar panels work well with heat pumps, but they will not usually power the heating system throughout winter. A 4 kWp array generates approximately 3,873 kWh annually, but only 32% of that electricity arrives between October and March, when our model places 75% of the heat pump’s annual electricity demand.
Contents
- 1 Can a heat pump run on solar panels?
- 2 How much of a heat pump’s winter electricity can solar panels cover?
- 3 Do you need a battery with solar panels and a heat pump?
- 4 Which electricity tariff is best for a heat pump with solar panels?
- 5 What grants are available for a heat pump with solar panels?
- 6 Is there VAT on heat pumps and solar panels?
- 7 FAQs
- 7.1 Can you run a heat pump on solar panels alone?
- 7.2 How many solar panels do I need for a heat pump?
- 7.3 Do I need a battery with a heat pump and solar panels?
- 7.4 Does Cosy Octopus work with solar panels?
- 7.5 Is the Boiler Upgrade Scheme grant affected by solar panels?
- 7.6 Is there VAT on a heat pump with solar panels?
- 8 Our Verdict
- 9 Sources
Key takeaways
- Solar generation: A 4 kWp system in central England generates approximately 3,873 kWh annually, including 1,245 kWh from October to March.
- Heat pump consumption: Our example household needs approximately 2,850 kWh annually, with 75% used during those same six months.
- Measured performance: A German property with a 12.3 kWp solar array and an 11.7 kWh battery covered 36% of its heat pump’s electricity demand.
- Electricity tariffs: Cosy Octopus offers off-peak electricity from 14.12p per kWh in London from 21 October 2026.
- Financial support: Eligible installations can receive a £7,500 Boiler Upgrade Scheme grant, while qualifying heat pumps, solar panels and batteries are zero-rated for VAT until 31 March 2027.
Can a heat pump run on solar panels?
Yes. Solar panels can generate electricity to power an air source heat pump, reducing the amount of electricity purchased from the grid.
However, generating enough electricity over a year is not the same as generating enough at the times your heating system needs it.
Fuse Energy cites Energy Saving Trust guidance suggesting that an average solar array of approximately 3.5 kWp can generate enough electricity annually to match a typical home’s heat pump consumption.
The main limitation is seasonal.
Solar panels produce considerably more electricity during spring and summer, while a heat pump’s demand increases in colder weather.
How much electricity does a heat pump use?
To illustrate the relationship, we have modelled a household currently using 9,500 kWh of gas annually, matching Ofgem’s medium-consumption figure.
Using an existing boiler efficiency of 84%, as assumed in a government impact assessment, the property needs approximately 7,980 kWh of useful heat.
The Electrification of Heat trial recorded a median seasonal heat pump efficiency of 2.80.
At that efficiency, the heat pump would use approximately 2,850 kWh of electricity annually.
We have distributed that demand across the year using heating degree days, with 20% of the heating requirement allocated consistently to hot water.
Solar generation vs heat pump electricity demand
The table compares a 4 kWp solar array with the modelled heat pump.
| Period | Solar generation | Heat pump consumption | Solar generation relative to heat pump demand |
|---|---|---|---|
| December to February | 488 kWh | 1,225 kWh | 40% |
| March to May | 1,238 kWh | 829 kWh | 149% |
| June to August | 1,365 kWh | 166 kWh | 822% |
| September to November | 781 kWh | 630 kWh | 124% |
| Whole year | 3,873 kWh | 2,850 kWh | 136% |
Solar generation is based on the European Commission’s PVGIS calculator for a south-facing 4 kWp array at 35 degrees in central England. Heat pump consumption is our illustrative model.
The figures show why solar panels and heat pumps complement one another without eliminating the need for grid electricity.
Between October and March, the panels generate approximately 1,245 kWh, while the heat pump needs around 2,127 kWh.
December presents the biggest challenge.
The solar array produces approximately 4.3 kWh per day, compared with around 13 kWh per day required by the heat pump.
Even if all the electricity generated by the panels went directly into the heat pump, it would cover only around a third of December’s demand.
How much of a heat pump’s winter electricity can solar panels cover?
The amount depends on the size of the solar installation, the heat pump’s efficiency, household electricity consumption and how much solar generation is available when the heating is running.
A useful real-world example comes from research by the Fraunhofer Institute for Solar Energy Systems in Germany.
Researchers monitored a property built in the 1960s in Freiburg with a 13.9 kW ground-source heat pump, a 12.3 kWp solar array and an 11.7 kWh battery.
According to pv magazine’s report, the system supplied approximately 36% of the heat pump’s electricity demand.
The figure included 51% coverage during hot water operation and 28% during space heating.
Even with a solar array around three times the size of our example, the property still needed grid electricity for most of its heating demand.
How much money could solar-powered heating save?
Every kWh of solar electricity used directly by a heat pump avoids purchasing that electricity from the grid.
At Ofgem’s October to December 2026 average electricity rate of 26.32p per kWh, the potential savings are:
| Solar contribution to heat pump electricity | Solar electricity used | Gross electricity saving | Net benefit after 4.1p export opportunity cost |
|---|---|---|---|
| 10% | 285 kWh | £75 | £63 |
| 20% | 570 kWh | £150 | £127 |
| 30% | 855 kWh | £225 | £190 |
| 36% | 1,026 kWh | £270 | £228 |
Calculations assume the alternative is exporting the electricity at 4.1p per kWh through an eligible SEG tariff. They exclude standing charges and changes in electricity prices.
The net benefit accounts for the export payments you would otherwise receive if the electricity were sent to the grid.
Export tariffs can pay considerably more than 4.1p.
Our guide to the best SEG export tariffs in the UK compares the available rates.
Do you need a battery with solar panels and a heat pump?
Not necessarily.
A home battery stores electricity generated by solar panels during the day, allowing you to use it later when the sun is no longer shining.
This can be particularly useful during spring and summer, when solar generation is high and the heat pump’s electricity demand is relatively low.
However, winter presents a different situation.
In December, our example solar array produces approximately one-third of the electricity required by the heat pump.
That leaves relatively little surplus solar electricity available for storage.
A battery may therefore provide more value in winter by charging from the grid during cheaper electricity periods and supplying the household when prices are higher.
Should you install a battery at the same time?
Installing a battery alongside solar panels and a heat pump can be convenient, but it is worth assessing the additional cost carefully.
The best battery capacity depends on how much electricity the property uses in the evening, the amount of surplus solar generation and the available electricity tariffs.
For some households, installing solar panels and a heat pump first, then reviewing actual electricity consumption before adding storage, may be a sensible approach.
Our guides to home battery storage, choosing the right battery size and home battery off-peak tariff savings explain the options.
Which electricity tariff is best for a heat pump with solar panels?
A time-of-use electricity tariff can help reduce heat pump running costs by offering cheaper electricity at certain times of day.
One example is Octopus Energy’s Cosy Octopus tariff, which is designed for homes with electric heating.
The tariff provides three lower-cost electricity periods:
- 4am to 7am
- 1pm to 4pm
- 10pm to midnight
There is also a more expensive peak period between 4pm and 7pm.
According to Octopus Energy’s published tariff data, the London variable rates change on 21 October 2026 to:
| Pricing period | Electricity rate |
|---|---|
| Off-peak | 14.12p/kWh |
| Standard | 28.80p/kWh |
| Peak | 43.19p/kWh |
These rates are specific to London and the stated tariff version. Other regions have different prices.
How much could Cosy Octopus save?
Using our example heat pump consuming 2,850 kWh annually, the following table illustrates the effect of moving electricity demand into cheaper periods.
| Electricity tariff and usage pattern | Annual heat pump electricity cost |
|---|---|
| Ofgem average rate, 26.32p throughout | £750 |
| Cosy Octopus standard rate only, 28.80p | £821 |
| Cosy Octopus, 30% during cheap periods | £695 |
| Cosy Octopus, 50% during cheap periods | £612 |
| Cosy Octopus, 70% during cheap periods | £528 |
Calculations use London rates effective from 21 October 2026 and exclude standing charges. They assume electricity not used during cheap periods is purchased at the standard rate, with no peak-rate consumption.
Moving 50% of heat pump electricity consumption into the cheaper periods reduces the annual cost by approximately £209 compared with using the standard Cosy rate exclusively.
For comparison, the same household’s original gas consumption of 9,500 kWh would cost approximately £757 at the current average gas unit rate of 7.97p.
The figures demonstrate why electricity tariff selection can make a significant difference to heat pump running costs.
Can solar panels and off-peak tariffs work together?
Yes.
Solar panels can supply electricity during daylight hours, while a suitable tariff allows the heat pump to use cheaper grid electricity at other times.
For example, a household might use solar electricity during the afternoon and schedule some heating or hot water production during lower-cost periods.
Pre-heating the home before the expensive evening peak may also reduce electricity purchases between 4pm and 7pm.
However, the best schedule depends on the property’s insulation, heating controls and the heat pump’s operating characteristics.
Our guide to the January 2027 energy price cap explains how electricity prices could change.
What grants are available for a heat pump with solar panels?
The main financial support for eligible heat pump installations in England and Wales is the Boiler Upgrade Scheme.
Under the scheme, qualifying homeowners can receive £7,500 towards an air source heat pump installation.
According to GOV.UK, an additional £1,500 is available until March 2027 for eligible homes currently heated by oil or LPG that are not connected to the mains gas network.
The heat pump must meet the scheme’s eligibility requirements.
Ofgem’s guidance for property owners explains that the installation must be completed by an MCS-certified installer, who applies for the grant on the customer’s behalf.
The scheme generally requires the heat pump to replace an existing fossil fuel or electric heating system.
Does having solar panels affect Boiler Upgrade Scheme eligibility?
The government and Ofgem guidance cited above does not identify solar panels as a reason for disqualification.
However, the grant is intended to support the eligible heat pump installation rather than pay for solar panels.
If you are arranging both systems together, ask the installer to confirm the grant eligibility and show the amount clearly on the quotation.
You can read more in our guides to heat pump grants and the Boiler Upgrade Scheme.
Is there VAT on heat pumps and solar panels?
Qualifying installations of air source heat pumps, solar panels and battery storage currently benefit from 0% VAT.
According to HMRC’s VAT Notice 708/6, the zero rate applies until 31 March 2027, with the reduced rate of 5% scheduled to apply from 1 April 2027.
This can make installation timing important for homeowners considering both technologies.
For example, if the combined eligible installation cost is £15,000 before VAT, a 5% VAT charge would add £750.
The actual VAT treatment depends on the installation and eligibility conditions.
Supply-only purchases are generally subject to standard VAT rules, so ask your installer to itemise the applicable VAT treatment in the quotation.
If you are considering both systems, our heat pump cost guide and guide to whether solar panels are worth it can help you compare the investment.
FAQs
Can you run a heat pump on solar panels alone?
Not reliably throughout the year.
Our example 4 kWp solar array generates approximately 3,873 kWh annually, more than the 2,850 kWh required by the heat pump.
However, December solar generation is approximately 133 kWh, compared with around 404 kWh of heat pump electricity demand.
You will normally still need electricity from the grid, particularly in winter and overnight.
How many solar panels do I need for a heat pump?
Our central England solar model produces approximately 968 kWh per installed kWp annually.
On that basis, a 3 kWp array could generate approximately the same amount of electricity over a year as a heat pump using 2,850 kWh.
However, that does not mean it can supply the heat pump directly throughout the year.
The correct solar system size should account for total household electricity consumption, roof space, export arrangements and the seasonal difference between generation and heating demand.
Do I need a battery with a heat pump and solar panels?
No. Solar panels and a heat pump can operate together without battery storage.
A battery allows you to store surplus solar electricity for later use, but its value depends on how much surplus electricity is available.
In winter, when heat pump consumption is highest, solar generation is often relatively low.
An off-peak electricity tariff may provide more immediate savings than a battery for some households.
Does Cosy Octopus work with solar panels?
Yes.
Cosy Octopus is designed for eligible homes with a heat pump or other qualifying electric heating and a smart meter.
Solar panels can supply electricity during the day, while the tariff offers cheaper grid electricity during three designated periods.
Check the import and export tariffs together before switching, as they have separate rates and conditions.
Is the Boiler Upgrade Scheme grant affected by solar panels?
Having solar panels is not identified as a disqualifying factor in the GOV.UK and Ofgem guidance referenced here.
The scheme provides £7,500 towards eligible air source heat pump installations in England and Wales.
Solar panel installation costs are not included in that grant.
Your installer should confirm eligibility and handle the grant application.
Is there VAT on a heat pump with solar panels?
Qualifying installations of air source heat pumps, solar panels and batteries are zero-rated for VAT until 31 March 2027.
HMRC’s published rules provide for a 5% reduced VAT rate from 1 April 2027.
The exact treatment depends on the equipment, installation and eligibility conditions.
Our Verdict
A heat pump with solar panels can be an effective way to reduce household energy costs, but the systems should be designed around the property’s actual requirements.
Solar panels can generate more electricity over a year than a typical heat pump consumes, yet their winter output is much lower than the heating system’s demand.
In our example, solar electricity covering 10% to 30% of the heat pump’s annual consumption provides a net benefit of approximately £63 to £190 a year at current rates and a 4.1p export tariff.
A suitable off-peak electricity tariff may deliver greater savings, particularly during winter.
We would recommend sizing the heat pump according to the property’s heat loss, selecting solar panels based on the household’s overall electricity requirements and considering battery storage only after assessing its additional financial benefit.
For eligible homeowners, the £7,500 Boiler Upgrade Scheme grant and the current 0% VAT treatment can also make installing both systems more affordable.
Eco Happy can help you explore suitable heat pump and solar installations and arrange a survey-based quotation for your property.
Sources
- European Commission – PVGIS Solar Generation Data
- European Commission – PVGIS Temperature Data
- Fuse Energy – Solar Panels and Heat Pumps
- MoneySavingExpert – Energy Price Cap Predictions
- UK Government – Boiler Efficiency Impact Assessment
- Energy Systems Catapult – Electrification of Heat Trial
- pv magazine – Combining Heat Pumps, Solar and Battery Storage
- Ofgem – Energy Price Cap Unit Rates and Standing Charges
- Ofgem – October to December 2026 Price Cap
- Octopus Energy – Cosy Octopus
- Octopus Energy – Cosy Variable Tariff Data
- Octopus Energy – Cosy Fixed Tariff Data
- Octopus Energy – Outgoing SEG Tariff Data
- GOV.UK – Boiler Upgrade Scheme Grant Amounts
- Ofgem – Boiler Upgrade Scheme for Property Owners
- HMRC – VAT on Energy-Saving Materials
