Plug in solar is the hot topic at the moment. A couple of panels, a small inverter, and a lead that plugs into an outside socket. No scaffolding, no installer, a few hundred pounds. People ask me about it every week, so here is my view as an electrician and a solar installer.
Short version: yes, it has a place. But there are caveats, and the big one is safety.
What plug in solar is
A plug in kit is usually one or two panels of around 400 watts each, a micro inverter that turns the DC from the panels into AC, and a cable with a plug on the end. You stand the panels somewhere sunny, plug in, and the inverter pushes power into your house through the socket. Whatever the house is using at that moment comes from the panels first and the grid second.
The appeal is obvious. It is cheap, it is quick, and if you rent or your roof is not suitable it may be the only solar you can have.
The safety points
The DC cables coming off the back of a solar panel are live whenever there is daylight on it. You cannot switch them off. On a roof mounted system those cables are fixed, protected and out of reach. On a plug in kit they are wherever you leave them.
If the cables are laid loosely against a fence or across the ground, they get damaged. If something chews through them and the two conductors touch, you get a flash over. It melts things and it can start a fire. It does not happen often, but it is a real risk on a system that a lot of people set up without thinking about it.
The other point is the socket. You are pushing power into a circuit that was designed to take power out. Most modern circuits with RCD protection cope fine. Older installations may not. I would want the home electrics checked before plugging anything in, and I would want the kit installed tidily, with the cables clipped and protected, not trailing across the patio.
What it will do for your bills
Be clear about this. A plug in kit will cover the background load of the house. The router, the fridge, the freezer, the television on standby, the things that tick over all day. On a sunny day one or two panels will cover that, and it adds up over a year because that background load never stops.
It will not run the house. It will not run the heating, the oven, or an EV charger. And it does not help in the evening when the lights come on, because the sun has gone. Some kits include a small battery that can run a few lights after dark, which helps, but it is not going to run a four bed house.
Per unit of power, plug in solar is expensive next to a roof mounted system. The kit is cheap, but a full system produces ten or twenty times as much for perhaps ten times the price. If you can have a proper system, that is where the value is.
Where to put it
The panels are big, around 1.7 metres by 1.1 metres each. They need somewhere sensible to go, pointing in a useful direction and out of shade. A panel facing a tree that shades it most of the day will make almost nothing. South, east or west facing, tilted, and clear of shadows is what you want.
My verdict
Plug in solar is a reasonable buy for someone who cannot have a roof system, understands what it will and will not do, and sets it up safely. It is a poor substitute for a proper system if your roof is suitable. If you are not sure which camp you are in, a free survey will tell you.
If you want a straight answer on your own house, we cover Cambridgeshire, Bedfordshire and Northamptonshire. We do a free survey and give you a clear written quote. Call 01480 400607 or read about our solar and battery installs.
Jason Pope
Owner, Selec Group