What could a kit save you?
Pick a kit and who's home in the day. You'll get a yearly figure, 10 and 20-year totals and the carbon saved.
Checked 4 November 2026
Get more from it
Use power while the sun's out
Your home uses the kit's power first. Put the washing machine, dishwasher or dryer on in daylight and more of it comes off your bill.
Where the figures come from
| What | Our figure | Source |
|---|---|---|
| Yearly generation, 800W kit | About 700 kWh (south-facing, 30° tilt, unshaded, North West England) | Energy Saving Trust: plug-in solar panels, updated 1 October 2026 |
| Kits over 800W | Panel power × 875 kWh per kW, less a fifth of the extra over 800W | Our estimate, from the Energy Saving Trust figure |
| Used at home | 40% to 70% (70% = busy four-person home, someone in all day) | Worked out from Energy Saving Trust figures |
| Unit rate | 26.32p per kWh, 1 October to 31 December 2026 (Direct Debit, GB average) | Ofgem price cap, announced 26 August 2026 |
| Power sent to the grid | Counted as nothing | Self-installed plug-in kits generally don't qualify for export payments |
| Most into your home | 799VA (3.5A), every kit | The maker's datasheets |
| 10 and 20-year totals | Today's unit rate, panels losing 0.5% a year | Our assumption |
| Carbon | 0.131kg CO₂e per kWh used at home | UK Government GHG conversion factors 2026 |
An estimate, not a promise. Direction and shade aren't modelled, and your result will vary with location, shade and when you use power.
The sums
- Generation. 700 kWh a year for an 800W kit, scaled down for smaller kits. Bigger kits are held to 800W at midday but make more in the mornings, evenings and on duller days: about 850 kWh for the Plus 1030W and 980 kWh for the Max 1260W.
- Saving. Generation × share used at home × unit rate, rounded to the nearest £5.
- 10 and 20 years. The yearly saving added up at today's rate, with the panels losing 0.5% of their output a year. If prices rise, you'd save more.
- Carbon. Each kWh you use from the panels instead of the grid saves about 0.131kg of CO₂e.
Change the generation figure or your unit rate under "Change the figures we use".