Why I’m still bullish on residential solar

The latest available DESNZ solar deployment release, published on 29 September 2026, covers August 2026. It records:

That is a 12.5% increase in recorded domestic installations in a year. Domestic solar accounts for roughly 30% of total UK solar capacity. These are provisional statistics, not a count of every solar-equipped household: the dataset has coverage limitations, and installations should not be treated as a household-adoption rate.

Solar also retains broad public support. In the Spring 2026 DESNZ Public Attitudes Tracker, 84% supported solar energy and 4% opposed it. That is support for the technology generally—not proof that everyone wants panels on their own roof or supports every local development.

Solar panels generate electricity from daylight, including in cloudy conditions, but output changes with the season, location, roof direction and shading. Winter production is much lower than summer production.

Two measures are often confused:

• Self-consumption: how much of the solar electricity you generate is used in your home rather than exported.
• Self-sufficiency: how much of your home’s electricity demand is met by that solar electricity.

They have different denominators. A home can generate more electricity over a year than it consumes and still buy electricity from the grid on most winter evenings. A normal home battery moves energy between hours; it does not store a summer’s surplus for winter.

The old article also used Ofgem’s 2,700 kWh benchmark as though it described an average single-family home. Ofgem’s updated decision lowered the medium-use benchmark for single-rate electricity meters to 2,500 kWh a year from 1 July 2026. It is a comparison benchmark, not a prediction for your property. Use your own annual consumption, especially if you have an electric vehicle or heat pump.

The government’s May 2026 solar cost release covers installations from April 2025 to March 2026. It gives useful context, but the definitions matter.

On a total installed capacity basis, the mean domestic installed cost was approximately £1,955 per kW for the 0–4 kW band and £1,645 per kW for the 4–10 kW band. These Great Britain figures include generation equipment, installation, connection and applicable VAT, but exclude batteries and other additional devices.

The often-quoted £1,595 per kW figure is the median across domestic and non-domestic installations in the smaller band. It is not a domestic-only average. Nor should the new total-installed-capacity series be compared casually with older declared-net-capacity figures: the government warns that changing the capacity measure changes the cost per kW.

For an existing home, the roof, access, scaffolding, electrical work and equipment choice still determine the quote. Get an itemised price and a generation estimate for your actual roof. Our solar costs guide explains the main items to compare.

Here is an illustration, not a promise of savings or a measured household. Assume:

• A 4 kWp array generating 3,600 kWh a year: an assumed yield of 900 kWh per kWp, not a UK-wide guaranteed output.
• Household electricity use of 3,500 kWh a year.
• 1,080 kWh of solar used directly in the home, with the remaining 2,520 kWh exported.
• An import price of 26.32p/kWh, the Ofgem October–December 2026 Direct Debit average for Great Britain.
• An assumed solar-only installation quote of £7,000.

The formula is straightforward: solar electricity used at home × avoided import price, plus exported electricity × export price. Export income is not an extra saving to add again to that total.

The 5p and 15p rates are comparison assumptions, not universal offers. SEG suppliers set their own rates and eligibility terms; compare the complete import/export arrangement. Standing charges remain payable. This simple payback holds prices and output constant and excludes finance, maintenance, replacements and degradation, so it is not a lifetime investment return.

A battery changes both sides of the calculation

Suppose a battery diverts an additional 1,000 kWh a year from export and returns 900 kWh to the home after losses. The extra avoided purchases are worth about £237 at the same import price. But the household gives up export income on the full 1,000 kWh:

• At a 5p export rate, the additional annual value is about £187.
• At a 15p export rate, it is about £87.

Those figures are before the battery’s purchase, finance and replacement costs. This is an annual-flow illustration, not a battery-sizing or hourly-dispatch model. Cheap overnight charging, time-varying tariffs and flexibility payments can change the result, but they must be modelled separately rather than assumed.

I remain positive about batteries. I just want the quote to show what the battery adds—not give it credit for savings the panels would already produce. Compare your own scenarios with our solar calculator and home battery guide.

There is a meaningful national opportunity without assuming every roof is suitable. Rather than repeat an uncertain estimate of Britain’s entire rooftop potential, here is a calculation anyone can check.

Assume each additional suitable roof receives 4 kWp, producing 900 kWh per kWp a year. One million roofs would add 4 GW of capacity and 3.6 TWh of annual generation.

For context, DUKES 2026 reports 96.2 TWh of UK household electricity consumption and 323.0 TWh of total UK electricity demand in 2025. Total demand includes uses and losses outside final household consumption.

These are scale illustrations, not forecasts or findings that this many additional suitable roofs exist. The percentages compare annual energy, not supply at every hour. They do not account for future demand growth, curtailment, storage losses or the grid investment needed to integrate more generation.

Even the one-million-roof example is a substantial contribution. I do not need to claim that residential solar can replace most national electricity supply to think it is worth pursuing.

My original wording on incentives was wrong. The Feed-in Tariff closed to new applicants from 1 April 2019, not 2024. Existing eligible participants continue receiving payments under their scheme terms.

Support has changed rather than vanished:

• The Smart Export Guarantee, launched in 2020, pays eligible small generators in Great Britain for metered exports. It does not provide the old Feed-in Tariff’s generation payment.
• Qualifying installed solar panels and electrical battery storage currently receive zero-rated VAT. Under the published rules, the relief runs to 31 March 2027, with a 5% rate scheduled afterwards. Equipment bought without qualifying installation is treated differently.
• The Warm Homes Plan sets out £15 billion of public investment, including support for low-income households and an intended low- and zero-interest finance offer for technologies such as solar and batteries. That is a programme commitment, not a £15 billion solar-only fund or an immediately available grant for every household. Eligibility and delivery differ by scheme and nation.

The policy question has moved on from simply bringing back the old tariff. I would judge support by whether it helps households get a well-designed system at a fair price, including people who cannot pay the upfront cost themselves.

Using an existing roof avoids taking additional land for that installation. Many domestic systems can also use permitted development rights. But planning exemptions have limits and conditions, and rules differ across the UK. Listed buildings, designated areas, roof suitability, building regulations and network-connection requirements still matter.

I would not repeat the earlier claim that residential solar is universally 20–30% cheaper for society than solar farms. A household saving the retail price of electricity is not the same calculation as the system-wide cost of producing a kilowatt-hour. Comparing a farm’s total capital cost with a household subsidy also leaves out the household’s own spending.

The government’s Solar Roadmap makes the case for solar at several scales and explicitly addresses network constraints and connection reform. Rooftop solar can reduce imports at the time it generates; a suitably controlled battery can move some energy into higher-demand hours. Neither removes the need to maintain and expand the network. Large amounts of local export can create constraints too.

That is why I have removed the earlier unsourced transformer-age claim and the blanket prediction that household solar would cut peak demand by 20–30%. Those are not necessary to make the case for roofs.

My priorities are practical: predictable support rather than stop-start incentives; finance that does not swallow the savings; routes for tenants and lower-income households to benefit; straightforward network connections; and clear standards for quotes, installation and aftercare.

For an individual household, I would start with the roof and the electricity bill, compare solar with and without a battery, and ask the installer to show the assumptions. For government, I would treat rooftops as a serious part of infrastructure policy alongside solar farms, wind, storage and the grid.

That is why I am still bullish. We already have a growing base of domestic installations, unused roof space and a technology households can put to work. The opportunity is substantial enough to stand on accurate numbers.