Solar panels and batteries: what to expect from your roof

Reviewed October 2026

How solar PV works in a home

Solar photovoltaic panels, usually shortened to solar PV, generate electricity from daylight. An inverter converts it into the kind your home uses. Whatever is being generated is used in the house first. Anything left over is stored in a battery, if you have one, or exported to the grid.

Panels need light, not heat, so they work all year, although a clear day in June produces far more than a dull one in December.

Is your roof suitable?

• Direction. An unshaded roof facing south is ideal. The Energy Saving Trust says a system facing east or west produces around 15 to 20% less.
• Shade. Nearby buildings, trees and chimneys reduce what a system produces.
• Space. An average system of about 4.5 kWp uses around 12 panels and covers 20 to 30 square metres of roof.
• Condition. The panels should last 25 years or more, so the roof beneath them needs to be sound before they go on.

What it costs, and what it earns

The Energy Saving Trust puts an average home system at around £7,600 to install. Installation in a home is zero-rated for VAT until 31 March 2027. The inverter will probably need replacing after about 12 years.

The return comes in two parts, and they are not worth the same.

A unit you use yourself is worth roughly twice a unit you export. That is why households who are at home in the day, or who can run appliances, a hot water cylinder or a car charger while the sun is out, see a quicker return.

On the Energy Saving Trust's figures, which use July 2026 prices and include export payments, a typical system pays for itself in about 9 to 12 years, depending on where you live and how much of the day someone is at home.

Batteries

A battery stores solar electricity you would otherwise export, so that you can use it in the evening. Paired with a time-of-use tariff, it can also be charged from the grid when electricity is cheap.

• Cost. The Energy Saving Trust gives a range of £1,500 to £10,000, and around £4,600 for a 5 kWh battery. A typical home system might be 10 kWh.
• Life. Typically 10 to 12 years, so a battery is likely to need replacing during the life of the panels.
• Return. The Energy Saving Trust's advice is candid: the savings can be significant, but are not always enough on their own to justify the cost. It depends on how much you would otherwise export, and on your tariff.

Grants and funding

• There is no national grant for solar panels that works like the Boiler Upgrade Scheme.
• Eligible low-income households can have solar panels fitted through the Warm Homes: Local Grant, where the council has funding.
• Installation in a home, including a battery, is zero-rated for VAT until 31 March 2027.
• The Smart Export Guarantee pays you for what you export. You need a meter that records exports every half hour, which usually means a smart meter, and an installation certified through MCS or an equivalent scheme.
• The Warm Homes Plan includes low and zero interest loans for solar panels and batteries. A first phase was due to open to borrowers from September 2026. When we last checked, the government had not published a list of lenders.

Planning permission in England

Solar panels on a house are usually permitted development, so no planning application is needed if they stay within these limits. The rules were updated on 27 August 2026.

• On a pitched roof, panels may project up to 200 mm from the roof slope and must not rise above the highest part of the roof, not counting the chimney.
• On a flat roof, the equipment may be up to 600 mm higher than the highest part of the roof.
• On a wall, panels may project up to 400 mm, or 200 mm where the wall adjoins a road.
• Listed buildings are excluded, and so are buildings in the grounds of one. You will need consent.
• In a conservation area, panels cannot go on a wall that faces a road, and a flat roof installation needs the council's prior approval.

Councils can remove these rights locally, so check with yours before work starts.

Plug-in solar

Since 27 August 2026 small plug-in solar kits have been legal to use in Great Britain. A kit produces up to 800 watts and plugs into an ordinary socket. The Energy Saving Trust says a kit must meet set standards and be registered before it is used, and that kits are better suited to a garden than a balcony. The government says one could save a household up to £110 a year.

They can be a way in for renters and for homes without a suitable roof, with a landlord's or freeholder's permission where it is needed. They are not a substitute for a roof system.

What solar does to your EPC

Solar panels usually raise an EPC rating, because the electricity they generate is counted in the calculation. Under the method in use since June 2025, a battery or a solar diverter can be recorded as well.

What we can record depends on the evidence. The MCS certificate states the size of the system in kilowatts peak, and with it we can enter the system exactly. Without it we have to work from what we can see on the roof, which is less precise. If you have had panels fitted since your last certificate, a new EPC will put them on the public register.

Choosing an installer

• Use an MCS certified installer. Without MCS certification, or an equivalent, you cannot join a Smart Export Guarantee tariff.
• Ask for the predicted annual generation in kilowatt hours, and how much of it you are expected to use yourself.
• Make sure the system is registered with your local electricity network operator. Solar panels and batteries both have to be.
• Keep the MCS certificate, the guarantees and the handover pack.

How Retrohaus helps

• Independent advice on whether solar suits the building, and what it would do to the rating
• A new EPC after installation, recording the panels and any battery
• Retrofit assessment and coordination where solar is fitted under a funded scheme

We also work with solar PV installers, providing the assessments, coordination and certificates that funded schemes require. See scheme and installer support.

Sources: Energy Saving Trust guides to solar panels (updated 1 October 2026) and battery storage (6 October 2026); GOV.UK, Smart Export Guarantee, the announcement on plug-in solar (26 August 2026) and guidance on registering energy devices; Ofgem, energy price cap for 1 October to 31 December 2026; HMRC VAT Notice 708/6; Planning Portal guidance on solar equipment and the 2026 amendment to the General Permitted Development Order; Elmhurst Energy on RdSAP 10 (May 2025). This page is general guidance, not a recommendation for any particular property.