The headline figure doing the rounds is £110 a year in savings. The government used it in their March 2026 announcement, and it has appeared in most of the press coverage since. It is a reasonable ballpark, but the actual saving you get depends on several things that are specific to your home and how you use electricity.
Where the £110 figure comes from
The Department for Energy Security and Net Zero based its estimate on a standard 800W system generating around 400 kilowatt hours per year, assuming a south-facing position and average UK sunshine. At the current Ofgem price cap rate of 27.69p per kWh, that works out to roughly £110 in electricity you do not buy from the grid.
Some independent estimates put the figure higher. A well-positioned south-facing system in central England can generate 650 to 700 kWh per year according to solar modelling data, which at the same rate saves closer to £180 annually.
What actually affects your saving
The single biggest factor is whether you are at home during the day. Plug-in solar feeds electricity directly into your home circuits as it generates. If nobody is using electricity at that moment, the surplus flows back to the grid, and without a Smart Export Guarantee meter setup, you will not be paid for it. The system is most valuable when your daytime electricity use is high.
Panel orientation matters almost as much. A south-facing panel at a 35 to 40 degree tilt gets the most out of UK sunshine. East or west-facing positions typically produce 60 to 70 percent of the optimal output. North-facing installations are not worth doing.
The electricity price cap also affects your return. Rates have been volatile in recent years. The higher the unit rate, the more each kilowatt hour you generate is worth to you.
How long before the kit pays for itself
A basic 800W kit currently costs between £400 and £600 from most suppliers. At a saving of £110 to £180 per year, the payback period works out at between three and five years. After that, every unit of electricity you generate is pure saving.
Adding battery storage extends the payback period but increases total savings by letting you use solar-generated electricity in the evening rather than losing it back to the grid. Whether that makes financial sense depends on the cost of the battery and your evening electricity usage.
The base load approach
One of the most effective ways to get value from a plug-in system is to focus on base load. These are the appliances that run continuously regardless of what else is happening: the fridge, the broadband router, devices on standby. A well-positioned 800W system in summer can comfortably cover this load during daylight hours, effectively stopping the meter on your most consistent energy costs.
You do not need to change your behaviour for this to work. The system quietly offsets what you would otherwise be drawing from the grid, every day the sun is shining.