What could a plug-in kit save you?
Pick a kit and tell us who's at home in the day. You'll see a yearly saving, the totals over 10 and 20 years, and the carbon you'd save.
Checked 4 November 2026
Getting more from your kit
Your home uses the kit's power the moment it's made, so the more you run in daylight, the more you save. Put the washing machine, dishwasher or tumble dryer on while the sun's out and a busy home can reach the top of the range.
The figures we use
| What | Figure | Where it's from |
|---|---|---|
| Power from an 800W kit | About 700 kWh a year, facing south at 30°, no shade, North West England | Energy Saving Trust: plug-in solar panels, updated 1 October 2026 |
| Kits with over 800W of panels | Panel power × 875 kWh per kW, less a fifth of the extra above 800W | Our estimate, built on the Energy Saving Trust figure |
| Share used at home | 40% to 70%, by who's home in the day (70% is a busy four-person home) | Worked out from Energy Saving Trust figures; 70% is our busy-home example |
| 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 a kit sends 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% of output 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 depends on where you live, your spot and when you use electricity.
The sums
- Power made. We start from about 700 kWh a year for an 800W kit. Kits with less than 800W of panels scale down. Kits with more make extra in the morning, the evening and on duller days, but are held to 800W at midday, so we scale them up by panel power less a fifth of the extra: about 850 kWh for the Plus 1030W and 980 kWh for the Max 1260W.
- Used at home. Only power your home uses as it's made saves you money: 70% for a busy home, 58% if someone's in most of the day, 49% if you're in and out, 40% if you're usually out.
- Saving. Power made × share used at home × unit rate, rounded to the nearest £5.
- 10 and 20 years. The yearly saving added up at today's unit rate, with the panels losing 0.5% a year. If prices rise, you'd save more.
Open "Use your own figures" to put in your own unit rate or generation figure.