Plug-in Solar vs Rooftop Solar: Which to Choose?

Plug-in solar and rooftop solar solve the same problem - cutting your electricity bill with your own generation - from opposite ends. One is a cheap, plug-and-go device for people who cannot touch the roof; the other is a permanent installation that generates several times more. The right choice is mostly decided by whether you own your home.

Plug-in solar becomes legal in the UK on 27 August 2026 (see our complete guide). Figures here are general guidance, not a guaranteed return.

The core difference is scale and permanence. Rooftop solar is a multi-kilowatt system wired into your consumer unit by an installer, generating thousands of kilowatt-hours a year and feeding surplus back to the grid for payment. Plug-in solar is a single 800W device that plugs into a socket, offsets what you are using at that moment, and is designed to be unplugged and taken with you. That 800W AC ceiling, and the battery-less "plug-in microgenerator" category it belongs to, are set by SI 2026/848, in force from 27 August 2026.

That difference cascades into cost, savings and who each one is for.

Rooftop, by a wide margin. A typical UK domestic rooftop system is several kilowatts and can generate several thousand kilowatt-hours a year. A plug-in system is capped at 800W AC by SI 2026/848 and realistically produces around 600 to 800 kWh a year - useful, but a fraction of a rooftop array. If raw generation is the goal and you can install on a roof, rooftop is the clear winner.

Plug-in solar has a far lower upfront cost and no installation bill, which is its whole appeal. But it earns nothing for exported power, so its saving is limited to what you self-consume - see our plug-in solar savings guide for the maths. Rooftop costs far more to install but generates more and earns export income through a Smart Export Guarantee (SEG) tariff - Ofgem requires licensed suppliers to pay for surplus electricity exported to the grid - so its total lifetime saving is much larger.

Payback is hard to compare cleanly today: no certified plug-in kit is on sale yet, so its price is unknown, while rooftop payback depends on system size, roof and tariff. As a rule of thumb, plug-in wins on low risk and low outlay; rooftop wins on total return over its life.

Renters, leaseholders and flat-dwellers who cannot install rooftop solar, and homeowners who want a low-cost, reversible way to shave the daytime base load without a big commitment. It is also the natural first step for anyone testing whether home solar suits them. See our guide for renters and flats.

Homeowners with a suitable, owned roof who want the largest possible bill reduction and export income, and who are comfortable with the upfront cost and a permanent installation - especially if they also want a battery, which plug-in solar cannot include under the 2026 rules: the government's plug-in solar consultation defines the plug-in microgenerator as a battery-less system.