What could a kit save you?
Choose a kit size and who's home in the day. See your yearly saving, the totals over 10 and 20 years, and the carbon you'd save.
Checked 4 November 2026
Use more of it at home
A kit saves you money on the power your home uses as it's made. Run the washing machine, dishwasher or tumble dryer while the sun's out and you'll use more of it. That's how a busy household gets to the top of the range.
Where the numbers come from
| Assumption | Figure we use | Source and date |
|---|---|---|
| Yearly generation, 800W kit | About 700 kWh (south-facing, 30°, unshaded, North West England) | Energy Saving Trust: plug-in solar panels, updated 1 October 2026 |
| Kits over 800W of panels | Panel power × 875 kWh per kW, less a fifth of the extra above 800W | Our estimate, from the Energy Saving Trust figure |
| Share used at home | 40% to 70%, by who's home in the day (70% = busy four-person home) | Worked out from Energy Saving Trust figures; 70% is our busy-household example |
| Unit rate | 26.32p per kWh, 1 October to 31 December 2026 (Direct Debit, GB average) | Ofgem price cap, announced 26 August 2026. The next cap is announced on 25 November 2026 |
| Electricity sent to the grid | Counted as zero | Self-installed plug-in kits generally don't qualify for export payments |
| Most a kit sends into your home | 799VA (3.5A) | The plug-in solar product rules (800VA limit) |
| Direction and shade | Not modelled | We don't have sourced figures for other directions or shade, so we don't guess |
| 10 and 20-year totals | Today's unit rate, panels losing 0.5% a year | Our assumption |
| Carbon saved | 0.131kg CO₂e per kWh used at home | UK Government GHG conversion factors 2026 |
An estimate, not a promise. Your result will vary with location, shade and when you use electricity.
How it's worked out
- Generation. We start from about 700 kWh a year for an 800W kit. Less panel power scales down. More panel power makes extra in mornings, evenings and duller days but is held to 800W at midday, so we scale up by panel power less a fifth of the extra: about 850 kWh for 1030W and 976 kWh for 1260W.
- Use at home. 70% for a busy family home (four people, someone in all day, washing run in daylight), 58% if you're home most of the day, 49% in and out, 40% out all day.
- 10 and 20 years. The yearly saving added up at today's unit rate, with the panels losing 0.5% of their output each year. If prices rise, you'd save more.
- Carbon. About 0.131kg of CO₂e for every kWh you use from the panels instead of the grid.
Saving = yearly generation × share used at home × unit rate, rounded to the nearest £5.
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