With energy prices still high and solar hardware costs falling, the question most homeowners are asking is: does solar actually pay? Here is an honest look at the numbers for 2026.
The Core Calculation
Solar payback depends on four variables:
- System cost — what you pay to install
- Bill savings — electricity you generate and use instead of buying from the grid
- SEG income — payments for electricity you export
- Electricity price — what you currently pay per kWh (and what it might rise to)
Using current 2026 figures:
| Variable | Value |
|---|---|
| Electricity unit rate (Ofgem cap) | 24.5p/kWh |
| Standing charge | £0.61/day |
| Average household consumption | 3,500 kWh/year |
| SEG rate (competitive tariff) | 15p/kWh |
| Solar system VAT | 0% |
Savings by System Size
| System size | Annual generation (kWh) | Used on-site (~50%) | Exported (~50%) | Bill saving | SEG income | Total annual benefit |
|---|---|---|---|---|---|---|
| 3kW | 2,400 | 1,200 | 1,200 | £294 | £180 | £474 |
| 4kW | 3,200 | 1,600 | 1,600 | £392 | £240 | £632 |
| 5kW | 4,000 | 2,000 | 2,000 | £490 | £300 | £790 |
| 4kW + battery | 3,200 | 2,400 | 800 | £588 | £120 | £708 |
Self-consumption rate increases with battery from ~50% to ~75%. Generation estimates assume South-facing, unshaded, UK average sun hours.
Payback Periods
| System | Installed cost | Annual benefit | Payback |
|---|---|---|---|
| 3kW no battery | £5,500 | £474 | 11.6 years |
| 4kW no battery | £7,500 | £632 | 11.9 years |
| 5kW no battery | £9,500 | £790 | 12.0 years |
| 4kW + 5kWh battery | £11,500 | £708 | 16.2 years |
| 4kW + 10kWh battery | £14,000 | £780 | 17.9 years |
Note: Battery storage extends payback because it adds £2,500–£5,000 in upfront cost. However, batteries provide resilience against grid outages and increase energy independence, which some households value beyond pure payback.
Who Gets the Best Return?
Solar ROI is highest for households that:
- Use lots of electricity during daylight hours — working from home, running a dishwasher or washing machine during the day, daytime EV charging
- Have high electricity consumption — above 4,000 kWh/year
- Have a south-facing roof with minimal shading
- Plan to stay in the property for at least 10 years
- Pair solar with a heat pump — heat pumps running on cheap solar electricity dramatically improve both systems’ economics
- Have an EV — solar + EV home charging is one of the best combined investments in 2026
Solar ROI is weakest for:
- East or north-facing roofs
- Heavily shaded roofs (trees, chimneys, neighbouring buildings)
- Households with very low electricity consumption
- Those likely to move within 5 years
- Rented properties (you cannot install solar without landlord consent)
What About Rising Electricity Prices?
If electricity prices rise, solar payback improves. The Ofgem cap has fluctuated between £1,568 and £3,549 since 2022. Analysts expect prices to remain above pre-2021 levels for the foreseeable future. Each 1p/kWh increase in the unit rate improves the annual return on a 4kW system by approximately £16.
Does Solar Affect Your Mortgage?
In 2026, solar panels are generally viewed positively by mortgage lenders. Higher EPC ratings (solar typically improves a home from band D to band C or above) are increasingly required for green mortgage products, which offer lower interest rates. If your home’s EPC rises from D to C as a result of solar, you may be eligible for better mortgage terms at your next renewal.
Realistic Expectations
Solar is not a quick-win investment. The payback period is measured in years, not months. It should be viewed as a long-term infrastructure investment with:
- Guaranteed returns — unlike market investments, savings are certain as long as you use electricity
- Hedge against energy price rises — the higher electricity goes, the better your returns
- 25-year panel warranty — most tier-1 panels guarantee at least 80% output at 25 years
- Low maintenance costs — annual cleaning and a monitoring check; inverter replacement likely after 10–15 years (£500–£1,000)
Planning Permission for Solar Panels
In most cases, solar panel installation on a domestic property in England, Scotland, and Wales is permitted development — you do not need planning permission, provided:
- The panels do not protrude more than 200mm from the roof surface (measured from the plane of the roof)
- The installation is not on a flat roof where panels would be visible from a highway
- The property is not a listed building (listed buildings require listed building consent)
- The property is not in a World Heritage Site (where additional restrictions may apply)
Properties in conservation areas may still be permitted development for roof panels, but cannot install panels on a wall or roof that faces a highway. If in doubt, contact your Local Planning Authority before installation.
Choosing a Solar Installer
With dozens of solar installers competing for business, quality varies significantly. To protect yourself:
- Use only MCS-certified installers — MCS (Microgeneration Certification Scheme) certification is required to access the Smart Export Guarantee and government grant schemes. Check at mcscertified.com
- Get at least three quotes — prices for the same system can vary by £1,000–£2,000 between installers
- Ask for a system design with shading analysis — a responsible installer should model your roof’s orientation and any shading from trees or chimneys before quoting
- Check reviews and TrustMark registration — long-established, well-reviewed installers are lower risk for warranty claims
- Confirm what the warranty covers — panels typically carry a 25-year performance warranty; inverters 5–10 years; workmanship 1–2 years minimum
Avoid installers who pressure you into a decision at the initial visit, quote without visiting the property, or offer prices that seem implausibly low.
Related Guides
- Solar Panels UK — Costs, Savings and Grants — detailed cost guide
- Smart Export Guarantee Guide — best SEG rates
- Green Technology hub — full guide to green home technology
- Heat Pump vs Gas Boiler Running Costs — pairing solar with a heat pump