The downsides, plainly The disadvantages of solar panels

Nine downsides to weigh up

1. The upfront cost. The Energy Saving Trust puts the average home system, about 4.5 kWp, at around £7,600. It typically takes 9 to 11 years to pay back in England, including export payments. Solar and batteries are 0% VAT until 31 March 2027; after that the rate is due to go back to 5%.
2. They make least when you need most. Output drops in winter, when days are short and the sun is low, and panels make nothing at night. Most of the year's electricity comes between spring and early autumn.
3. Not every roof suits. A south-facing roof is best. East and west-facing roofs produce about 15 to 20% less, according to the Energy Saving Trust, and a north-facing roof isn't recommended. Shade from trees, chimneys or nearby buildings cuts output too.
4. Daytime power, evening use. Panels generate in the day, while many homes use most electricity in the evening. Export pays around 12p a unit while buying from the grid costs more than twice that, so what you can't use yourself is worth less. A battery helps, but the Energy Saving Trust puts home batteries at £1,500 to £10,000.
5. No power in a power cut. A standard system switches off when the grid goes down, for the safety of engineers working on the lines. Backup needs extra equipment and setup.
6. The inverter needs replacing. Panels should last 25 years or more, but the inverter usually needs replacing at least once, often after around 12 years. MoneySavingExpert puts a replacement at around £800.
7. Export rates vary a lot. Smart Export Guarantee tariffs range from about 1p to 25p a unit, and the best rates are often tied to buying your electricity from the same supplier.
8. Planning limits in some places. Listed buildings always need consent, and conservation areas, national parks and flats have extra rules. Most houses don't need permission at all.
9. They may not add value when you sell. Which? found most estate agents said solar panels don't typically increase a home's value, though they can make it easier to sell. Keep your MCS certificate and paperwork for the buyer.

Do solar panels damage your roof?

They shouldn't, if they're fitted properly. MCS installation standards require the installer to check the roof structure can take the panels. On a pitched roof, panels sit on rails fixed to the rafters through brackets that slip under the tiles, so the roof stays weatherproof. The risk comes from rushed or uncertified work, so check who you're hiring.