Short answer: They can be, for flats, balconies and renters. Compliant kits up to 800W have been legal in Great Britain since 27 August 2026 and plug into a normal socket. They make a small amount of power compared with a roof system, so on a house with a suitable roof, a full system is usually better.
What changed on 27 August 2026
Until this summer, solar panels that plug straight into a wall socket could not legally be sold or used in the UK. New regulations, SI 2026 No. 848, changed that from 27 August 2026 (legislation.gov.uk). Compliant kits can now be bought and plugged into a normal domestic socket, without an electrician, as long as they stay within the limits.
The main limit is size. A compliant plug-in kit is capped at 800W of output. That is roughly a fifth of an average home roof system, which the Energy Saving Trust puts at 4.5 kWp (Energy Saving Trust).
What a plug-in kit makes in Derby
PVGIS gives a south-facing panel in central Derby about 979 kWh a year per kWp at a 35 degree tilt (PVGIS). A full 800W kit set up like that would make roughly 780 kWh a year. On a balcony, panels are often mounted near vertical, face east or west, or sit in partial shade from the building, so the real figure is usually lower.
The saving comes from using that power as it is made. At the East Midlands price cap of 25.36p per kWh (Ofgem), every unit you use instead of buying is worth that. There is no battery storage in the first phase of the rules, so power made while nothing is running is lost.
Who plug-in solar suits
Plug-in kits make most sense for people who can’t have a roof system: flat owners with a south-facing balcony, renters, and people with a small outbuilding or a sunny garden wall. They are cheap to try and easy to take with you when you move.
For a house with a roof that faces south, east or west, a roof system makes several times more power, can include a battery, and usually pays back better over its life. How much do solar panels cost in Derby? sets out those numbers.
Own a house with a sunny roof?
A full system makes several times more than a plug-in kit. Call for a free quote.
Permission and safety
If you rent, you need your landlord’s written permission for anything fixed to a balcony, wall or railing. Leaseholders need the freeholder’s approval as well. Buy a kit that is clearly marked as meeting the UK plug-in solar requirements, rather than one made for another country, and register it through the Energy Saving Trust’s checklist.
In a conservation area or on a listed building, check with the council before fixing panels to a wall that faces the street. The national rules for solar on houses in those areas are stricter, as the planning guide explains.
Bottom line
Plug-in solar kits up to 800W have been legal in Great Britain since 27 August 2026. They suit flats, balconies and renters who can't have a roof system. On a house with a suitable roof, a full system makes far more power. Call 01332 919162, 9am to 7pm, 7 days.