How does plug-in solar work?
Plug-in solar works by turning daylight into electricity your home can use, then feeding it into your mains via a normal socket. A panel makes power, a small box called a microinverter converts it into the kind of electricity your mains runs on and flows into your home for your appliances to use. The less you draw from the grid, the more you save. No rewiring, no installer and no fuse-box work.
The short version
Daylight hits the panel and the panel produces direct current (DC). The microinverter behind it converts that into alternating current (AC) at 230 volts and 50 hertz, which is exactly what comes out of your wall. That AC flows in through the plug and joins the electricity already moving around your home. Your fridge, router and anything else switched on use it first. Whatever they don’t use, you draw from the grid as normal.
Daylight becomes DC electricity
DC is converted to AC, matched to your mains
AC flows in through a normal socket
Appliances use the solar power first
The saving comes from using what you generate
Electricity always flows to the nearest demand, so the power your kit makes gets used by your own appliances before anything else. A unit (a kilowatt-hour, or kWh, the measure on your electricity bill) that you generate and use yourself saves you the full price you’d have paid for it, around 24.5p, giving you immediate payback. A unit you export to the grid earns only a few pence at most, and only then if you’ve signed up to the Smart Export Guarantee (SEG), a scheme you apply for separately through your energy supplier. So plug-in solar pays you back best when you’re using power during daylight: the washing machine on in the afternoon, the dishwasher during the day, devices charging while the sun is up. We go into the numbers in our savings guide.
What happens when it’s cloudy or dark
Output rises and falls with the daylight. On a bright day the kit runs near its full rating; under heavy cloud it makes less but keeps going, because panels run on daylight rather than direct sun. After dark the output is negligible; moonlight is around 400,000 times dimmer than direct sunlight, far too faint to register in any meaningful way, and your home runs on the grid as it always does. The system handles that transition automatically. We cover this in more detail in our guide to solar in cloudy UK weather.
The microinverter is doing the clever work
Two jobs sit inside that one small box. First, it synchronises its output precisely to the grid’s voltage and frequency, so the electricity it adds blends in cleanly. Second, it watches the grid constantly and if the mains drops it shuts off within about a second so it can’t push power into a dead network. That second job is the core safety feature and it’s covered in our guide to whether plug-in solar is safe.
Can you see what it’s making?
Yes. The microinverter reports what it’s generating, so you can see your output on your phone rather than guess. Watching the numbers is also the easiest way to learn the habit that saves the most: running the things that use power while the sun is up.
Common questions
A panel turns daylight into DC electricity. A microinverter converts that into AC at 230V and 50Hz, the same as your mains. It flows in through a normal plug and your appliances use it first, so you draw less from the grid.
No. That’s the point of plug-in solar. It connects through a standard socket rather than being hardwired into your consumer unit, which is what made it electrician-only before the rules changed.
Two things. It converts the panel’s DC into mains-matched AC and provides the safety cut-off (anti-islanding) that shuts the system down within about a second if the grid goes off.
You save the most by using your own power as it’s generated, worth around 24.5p per unit (a kilowatt-hour, or kWh, the measure on your electricity bill). Exporting spare power to the grid earns only a few pence per unit, and only if you’ve signed up to the Smart Export Guarantee (SEG) through your energy supplier; it’s not automatic. Plug-in solar pays back best when you use electricity during daylight.
No. Panels need daylight, so the kit makes nothing after dark and your home runs on the grid as normal. Output scales up and down with how much light there is.
Solar for everyone
We didn’t build a solar company for people who already have solar. We built one for the millions who’ve never been able to benefit from it.
See the Sola kits- ENA Connect Direct: Engineering Recommendation G98, covering grid-connection, synchronisation and anti-islanding for small generators.
- ENA Type Test Register, listing type-tested microinverters.
- Energy Saving Trust: Solar panels: explains DC-to-AC conversion and cloudy-day generation.
- Ofgem: Smart Export Guarantee (SEG) for generators: eligibility and how to apply.
This guide is general information, not legal or electrical advice. Rules and product standards for plug-in solar are still settling in 2026, so check the current position for your property and network operator before you buy or connect. Last updated: 30 July 2026.