Solar panels are worth it for most London homes with a south, east or west facing roof, someone at home in the day or a battery, and plans to stay for at least the payback period of 7 to 12 years. They are not worth it on a north facing or heavily shaded roof, on a house you expect to sell within a few years, or when the loft and walls are still uninsulated and the same money would cut more energy. Here is the honest version for each case.
Key takeaways
- A south facing 4 kW system in London makes around 3,400 to 3,800 kWh a year; east or west facing roughly 15 to 20% less.
- The value is in the electricity you use yourself. Export is paid at only 5p to 15p per kWh under the Smart Export Guarantee.
- Typical payback is 7 to 12 years on a £5,000 to £8,000 system, against a panel life of 25 years or more.
- An EV or a heat pump makes solar more worthwhile because they soak up the daytime power.
- A battery raises self-use but adds £3,000 to £7,000, so it needs its own sums.
- Insulate first: a well insulated home needs less energy and a smaller, cheaper system.
Are solar panels worth it in 2026?
Yes, for the average London house with a usable roof, on the numbers alone. A 4 kW system costs £5,000 to £8,000 installed at 0% VAT, and is worth an indicative £400 to £850 a year in electricity you do not buy plus export payments. That is a 7 to 12 year payback on equipment that keeps producing for 25 years or more.
The "for the average house" part is doing a lot of work in that sentence. Roof direction, whether anyone is home in the day, and whether you have or plan an electric car or a heat pump each swing the answer. The sections below take them one at a time.
| Situation | Worth it? | Why |
|---|---|---|
| South facing roof, someone home in the day | Yes | High generation, high self-use, payback at the short end |
| East or west facing roof | Usually | Around 15 to 20% less output, still a sensible payback |
| North facing or heavily shaded roof | No | Output too low to recover the cost in a reasonable time |
| Everyone out 9 to 5, no battery | Marginal | Most power is exported at 5p to 15p per kWh |
| Everyone out 9 to 5, with a battery | Usually | Battery shifts daytime power into the evening |
| Electric car or heat pump | Yes | Large daytime loads use the power instead of exporting it |
| Selling within 3 to 5 years | Probably not | You will not reach payback; some value is recovered in the sale price |
| Loft or walls still uninsulated | Not yet | Insulation cuts more energy per pound; do that first |
Does the roof have to face south?
No, but it helps. South is the benchmark: around 3,400 to 3,800 kWh a year from a 4 kW system in London. East or west gives roughly 15 to 20% less, and one array on each pitch spreads generation across the morning and evening, which can suit a working household better than a single south array that peaks at lunchtime.
Shading matters more than direction. A chimney, a dormer, a neighbour's gable or a street tree can shade part of an array for hours, and on a string inverter one shaded panel drags the whole string down. A proper survey checks the sky from the roof. A north facing pitch is not worth panelling; if that is your only roof, a battery on an off-peak tariff may do more for your bills than panels.
Why daytime use decides the payback
Solar power is worth the full import price when you use it and only the export price when you do not. With import at around 25p per kWh and export at 5p to 15p, a unit used in the house is worth two to five times a unit sent to the grid. Everything about payback follows from that.
- Someone home in the day. Working from home, retired, young children: self-use of 40 to 50% is realistic without a battery, and payback sits at the short end.
- Everyone out until six. Self-use can fall to 25 to 35%. Payback stretches to the long end unless you add storage.
- Timers and habits. Running the dishwasher, washing machine and immersion heater at midday costs nothing and can lift self-use by 10 to 15 percentage points.
Do a battery, an EV or a heat pump change the answer?
Battery
A 5 kWh battery costs £3,000 to £4,500 and a 10 kWh battery £4,500 to £7,000, at 0% VAT, with a life of around 10 years or 6,000 cycles. It stores midday power for the evening, can charge from the grid at off-peak rates, and usually lifts self-use to 60 to 80%. It also adds cost, so the combined payback is often similar to panels alone, with a higher annual saving. See is a home battery worth it.
Electric car
An EV is the best use of surplus solar. A solar-aware charger diverts spare power to the car, so electricity that would have been exported at 5p to 15p replaces petrol instead. If the car is at home in the day, solar goes from marginal to clearly worth it. See EV charger installation cost.
Heat pump
A heat pump uses most of its electricity in winter, when the panels make the least, so solar does not run the heating. It does cover hot water and the shoulder months, and a heat pump household uses more electricity overall, so more of the solar is used at home. The order of works still matters: fabric, then heat pump, then solar. See do I need to insulate before a heat pump.
Is solar worth it if you might move?
If you expect to sell within three to five years, you will not reach payback through bills. Solar does add to a home's appeal and can lift the EPC rating, which matters to buyers and to any landlord facing the EPC C target, but it rarely returns the full installed cost in the sale price. Treat it as a comfort and running-cost decision for a home you plan to keep.
If you own the home for the long term, the calculation reverses: after payback the system produces free electricity for another 13 to 18 years on a typical 25 year panel warranty, and the inverter is the only major part likely to need replacing in that time.
Why we say insulate before you generate
We are an insulation company and we arrange solar because customers ask for it after an insulation job. The order matters. A loft top-up costs £400 to £900 and cuts heat loss through the roof at once. Draught proofing is £250 to £700 for a whole house and pays back in months. None of that depends on the sun being out.
Once the fabric is right, the house needs less energy and the solar system can be sized to what you use rather than to what the roof will take. A free heat loss survey puts the measures in order with indicative costs, and solar is quoted alongside them, arranged and project-managed by Stay Warm and installed by accredited, MCS certified installers.
Frequently asked questions
How long does it take for solar panels to pay for themselves?
Typically 7 to 12 years for a 4 kW system costing £5,000 to £8,000 in London. High daytime use, an EV or a battery push it towards the short end; a household out all day with no storage sits at the long end.
Are solar panels worth it without a battery?
Yes if someone is home in the day or you can shift appliance use into daylight hours. If the house is empty until evening, most of the power is exported at 5p to 15p per kWh and the payback stretches, so a battery is worth costing.
Are solar panels worth it on an east or west facing roof?
Usually. Output is roughly 15 to 20% lower than a south facing roof, so payback is a year or two longer. Panels on both an east and a west pitch spread generation across the day, which suits many working households.
Is there a grant for solar panels?
Not a cash grant for most homeowners. The support is 0% VAT until 31 March 2027, the Smart Export Guarantee for exported power, and the Warm Homes: Local Grant for owner occupiers on a low income in an EPC D to G home, where the council appoints the installer. See our solar panel grants guide.
Should I insulate before fitting solar?
Yes. Loft insulation, draught proofing and wall insulation cut the energy the house needs regardless of the weather, and a better insulated home can run a smaller solar system and a smaller heat pump. Our free heat loss survey puts the measures in order.