Solar Panels vs Heat Pumps: Which Should You Install First?
Solar panels and heat pumps can both reduce a home’s dependence on conventional energy, but they solve different problems.
Solar panels generate electricity. A heat pump replaces or supplements the system that heats your home and hot water. Therefore, the right technology to install first depends on your current heating system, roof, insulation, budget and renovation plans.
For many UK homeowners with a functioning gas boiler and a suitable roof, solar panels are usually the simpler first investment. They involve less disruption, can reduce electricity bills immediately and can later help supply some of the electricity used by a heat pump.
However, a heat pump may deserve priority when your boiler needs replacing, you use expensive oil, LPG or direct electric heating, or you are already renovating the property.
Quick answer
Most UK homeowners should consider installing solar panels first when their existing heating system is reliable, their roof is suitable and they want a relatively straightforward way to reduce electricity costs.
Install a heat pump first when your boiler is approaching replacement, you are moving away from oil or LPG, or building work already provides an opportunity to improve insulation, radiators and hot-water storage.
Neither technology should automatically come before essential insulation. A heat pump must be designed around the property’s calculated heat loss, while solar performance depends on roof orientation, shading and household electricity use. The strongest long-term result is often an integrated plan in which insulation, solar panels, a heat pump, smart controls and an appropriate tariff work together.
Solar panels vs heat pumps at a glance
| Factor | Solar panels | Air source heat pump |
|---|---|---|
| Main purpose | Generate electricity | Provide heating and hot water |
| Typical UK installation cost | Around £7,600 for a typical 4.5kWp system | Around £12,000 before eligible funding |
| Current support | No universal dedicated UK solar grant; local or household schemes may apply | £7,500 Boiler Upgrade Scheme grant in England and Wales, rising to £9,000 for qualifying off-gas-grid oil or LPG replacements |
| Property requirement | Suitable roof or ground-mounted location | Heat-loss survey, outdoor unit space and usually hot-water storage |
| Disruption | Usually low | Moderate; radiators, pipework or cylinder may need changing |
| Best for | Homes with good roofs, daytime electricity use, EVs or future electrification plans | Homes replacing old, inefficient or expensive fossil-fuel heating |
| Winter performance | Generates less during shorter winter days | Works in winter but consumes more electricity as outdoor temperatures fall |
| Typical first choice | Functioning boiler and suitable roof | Failing boiler, oil/LPG heating or major renovation |
Energy Saving Trust places the typical cost of a 4.5kWp domestic solar system at approximately £7,600 and estimates payback periods of roughly nine to twelve years in several Great Britain locations, depending on location and usage. Its current benchmark for an air source heat pump is approximately £12,000 before grants.
What should come before either technology?
Before deciding between solar panels and a heat pump, check whether the property is wasting unnecessary energy.
Insulation and draught-proofing do not generate energy, but they reduce how much energy the home requires. This is particularly important for heat pumps because the system must be sized according to heat escaping through the walls, roof, floor, windows and ventilation.
A poorly insulated property can still have a heat pump, but it may require a larger unit, higher flow temperatures, larger radiators and more electricity. Improving practical areas of heat loss first can reduce the heating requirement and improve comfort.
The correct starting point is therefore:
- Address urgent repairs, damp and ventilation problems.
- Complete sensible insulation and draught-proofing.
- Assess the roof and electrical supply.
- Calculate the property’s room-by-room heat loss.
- Plan the technologies as one system, even if they will be installed at different times.
When should you install solar panels first?
Overview
Solar photovoltaic panels convert daylight into electricity that can power appliances, an EV charger, battery storage and, eventually, a heat pump.
Panels still generate electricity on cloudy days, although output varies with daylight, orientation, shading and location. A typical 4.5kWp system may require approximately 20–30m² of roof area. South-facing roofs normally produce the most electricity, while east- and west-facing roofs can also be viable.
Solar panels are best installed first when:
- Your gas boiler remains reliable.
- You have an unshaded south-, east- or west-facing roof.
- You want a less disruptive first-stage improvement.
- You work from home or can shift electricity use into daylight hours.
- You own an EV or expect to purchase one.
- Your future plans include a heat pump or battery.
- Your immediate priority is reducing imported electricity.
Key advantages
Solar panels normally require fewer internal alterations than a heat pump. Installation may only require scaffolding, roof mounting equipment, an inverter, cabling and final electrical connections.
Surplus electricity can be exported under an eligible Smart Export Guarantee tariff or stored for later. Using solar electricity directly will often be more valuable than exporting it because imported electricity normally costs more than the amount paid for each exported unit.
Solar panels also have a long working life. Energy Saving Trust advises that panels should last at least 25 years, although an inverter may need replacing after approximately 12 years.
Things to consider
Solar generation is highest in spring and summer, while heat-pump demand is greatest in winter. Solar panels will therefore not power a heat pump independently throughout the year.
A battery can move electricity from daytime to evening, but it cannot store summer energy for winter. System sizing should be based on annual generation, household consumption, export rates and the value of using electricity on site.
Example UK use case
A family has a ten-year-old but functioning gas boiler, a south-west-facing roof and an electric car. Installing solar first can reduce household and vehicle-charging imports now. When the boiler eventually needs replacing, the property is already partly prepared for electric heating.
Expert recommendation
Choose solar first when there is no urgent need to replace the heating system. Ask the installer to consider future heat-pump demand, battery compatibility, inverter capacity and possible EV charging rather than designing only for present electricity use.
When should you install a heat pump first?
Overview
An air source heat pump uses electricity to transfer heat from outside air into the home’s heating and hot-water system. It commonly delivers around three units of heat for each unit of electricity used, although actual seasonal performance depends on temperatures, radiator sizing, flow temperature, controls and installation quality.
A heat pump is best installed first when:
- Your boiler has failed or needs replacing soon.
- You use oil, LPG or direct electric heating.
- You are completing an extension or major renovation.
- Underfloor heating or new radiators are already being installed.
- You want to remove fossil-fuel heating.
- Your roof is shaded, unsuitable or due for replacement.
- You qualify for significant heat-pump funding.
In England and Wales, the Boiler Upgrade Scheme currently provides £7,500 towards qualifying air-to-water and ground source heat pumps. From 21 July 2026, qualifying off-gas-grid properties replacing oil or LPG can receive £9,000. Separate arrangements apply in Scotland and Northern Ireland.
Key advantages
A heat pump addresses one of the largest sources of household energy consumption: space heating and hot water.
Installing it when a boiler already needs replacing avoids paying for another fossil-fuel system that may remain in place for many years. Renovation also provides an opportunity to install larger radiators, underfloor heating, upgraded pipework and suitable hot-water storage with less additional disruption.
Things to consider
A heat pump is not a direct boiler swap. Most air-to-water systems require an outdoor unit and a hot-water cylinder. Some radiators may need replacing because heat pumps normally circulate water at lower temperatures than conventional boilers.
Running-cost savings are not guaranteed. From July to September 2026, Ofgem’s average Direct Debit price-cap rates are 26.11p/kWh for electricity and 7.33p/kWh for gas. Because electricity costs considerably more per unit, heat-pump efficiency, controls and tariff selection strongly affect the financial result.
Example UK use case
A rural homeowner has an ageing oil boiler and plans to renovate the kitchen and ground floor. Installing the heat pump first may allow the owner to use available grant support, remove oil storage and install underfloor heating while floors are already being replaced.
Expert recommendation
Prioritise the heat pump when heating replacement is unavoidable or the existing fuel is expensive. Do not approve a quotation without room-by-room heat-loss calculations, proposed flow temperatures, radiator outputs and estimated Seasonal Performance Factor.
How should you choose the installation order?
| Your situation | Recommended first step | Why |
|---|---|---|
| Reliable gas boiler and suitable roof | Solar panels | Lower disruption and immediate electricity generation |
| Boiler likely to fail within two years | Heat-pump assessment | Avoid paying for an interim boiler without comparing alternatives |
| Oil or LPG heating | Heat pump | Higher potential grant and reduced fossil-fuel dependence |
| Major extension or renovation | Heat pump planning | Heating emitters, pipework and insulation can be incorporated into the work |
| EV owner with high daytime use | Solar panels | More opportunities to use generated electricity on site |
| Poorly insulated home | Fabric improvements | Reduces heating demand before system sizing |
| Shaded or unsuitable roof | Heat pump | Solar output may not justify the investment |
| Limited budget and no urgent heating issue | Solar panels | Usually simpler to phase and easier to install independently |
A practical decision process is:
- Review your heating system. Establish its age, condition and likely replacement date.
- Check the building fabric. Identify practical insulation, draught-proofing and ventilation improvements.
- Assess solar suitability. Check orientation, shading, roof condition and available area.
- Complete a heat-loss calculation. Do not size a heat pump from floor area or boiler capacity alone.
- Model energy use. Include heating, appliances, EV charging and planned future changes.
- Compare tariffs and exports. A specialist heat-pump or time-of-use tariff can materially affect savings.
- Create a staged plan. Specify what should be installed now and how it will connect to future equipment.
Will solar panels make a heat pump cheaper to run?
They can, but the benefit should not be overstated.
Solar panels generate some electricity that would otherwise be purchased from the grid. However, the seasonal mismatch means they produce the least energy during the period when space-heating demand is highest.
The most effective integrated systems combine efficient heat-pump operation with solar generation, smart controls, thermal or electrical storage and an appropriate tariff. Recent Energy Saving Trust modelling found that technology choice, performance and tariff selection must be considered together; its strongest combined scenarios achieved materially larger savings than installing equipment without tariff optimisation. Actual results remain property-specific.
How much will each system cost and save?
Use national cost figures as initial benchmarks, not quotations.
Solar pricing depends on system size, scaffolding, roof access, panel specification, electrical work and roof condition. Heat-pump pricing depends on heat loss, output, cylinder requirements, radiator changes, pipework, controls and electrical upgrades.
Solar payback may be easier to estimate because generation can be modelled from the roof and location. Heat-pump payback is more sensitive to the heating system being replaced, grant eligibility, seasonal efficiency and electricity tariff.
A property survey is required before relying on any savings or payback forecast.
Why the installer matters
Installation quality can make the difference between a well-performing renewable-energy system and an expensive disappointment.
For solar, the installer should assess shading, roof condition, structural suitability, inverter design, expected generation, export arrangements and fire-safe electrical installation.
For a heat pump, the installer should complete accurate heat-loss calculations, size every radiator, design for low flow temperatures, position the outdoor unit responsibly and explain weather compensation and controls.
MCS is the recognised UK quality mark for small-scale renewable installations. Using an appropriately certified installer is also normally required for government heat-pump funding and may be necessary for export arrangements and consumer protection.
Before choosing one technology, ask Simple Green Energy for a whole-home assessment covering roof suitability, heat loss, current energy use, future EV demand and available funding.
Frequently asked questions (FAQs)
Clear answers about installing solar panels and heat pumps, winter performance, insulation, costs, payback, radiators, hot-water cylinders and future battery storage. Speak to Simple Green Energy .
Planning solar and a heat pump?
Speak with Simple Green Energy about installation order, expected electricity demand, heat loss, radiator sizing, hot-water storage and whether battery storage suits the complete system.
Discuss my whole-home systemConclusion: which should you install first?
For the average homeowner with a suitable roof and a functioning gas boiler, solar panels are generally the logical first installation. They are less disruptive, begin generating electricity immediately and can support future electrification.
A heat pump should normally come first when the existing boiler needs replacement, the home relies on oil or LPG, or renovation work makes it practical to improve insulation and heating emitters at the same time.
The best answer is not based on the technology with the strongest headline saving. It is based on the property’s condition, energy demand and long-term upgrade plan.
Start with a professional survey, correct obvious heat loss and choose equipment that can work together. That approach is more likely to produce reliable comfort, realistic savings and long-term value than purchasing either technology in isolation.
