What Will a Kit Save on Your Bill? Let's Work It Out

Pick a kit and tell us who's in during the day. You'll see a yearly saving, the total over 10 and 20 years, and the carbon you'd save. With a busy family home and the Max 1260W, that's around £180 a year.

Checked 4 November 2026

Your details in

Kit

Who's home in the day?

Where will the panels sit? Facing roughly south, no shade Facing east or west, or shaded for part of the day Not sure yet

Change the figures we use

Yearly generation for an 800W kit (kWh)

Your unit rate (pence per kWh)

Your saving out

Estimated bill saving

around £130 a year

Estimated generation: 700 kWh a year
Used in your home: 70%
Over 10 years: around £1,270
Over 20 years: around £2,490
Carbon saved: about 64kg a year
Range, 40–70% used: £75–£130
Unit rate: 26.32p per kWh

An estimate, not a promise. It assumes a south-facing, unshaded spot at 30°, North West England, about 700 kWh a year from an 800W kit (Energy Saving Trust), 40–70% of it used at home, and the Ofgem price cap unit rate of 26.32p per kWh (1 Oct to 31 Dec 2026). Electricity you send to the grid isn't paid for. Your result will vary with location, shade and when you use electricity.

See this kit

How we work it out (no fiddled numbers)

What we assume	The figure	Where it's from
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 with more than 800W of panels	Panel power × 875 kWh per kW, less a fifth of the extra above 800W (Plus 1030W about 850 kWh, Max 1260W about 980 kWh)	Our estimate, worked from the Energy Saving Trust figure
Share used at home	40% to 70%, by who's in during the day. 70% is a busy four-person home with someone in all day	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. Next cap announced 25 November 2026
Power 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), every kit	The maker's datasheets
Direction, shade and wall mounting	Not modelled	We haven't got sourced figures for these, so we don't guess. Facing away from south, or shade, means less
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

Saving = yearly generation × share used at home × unit rate, rounded to the nearest £5. It's an estimate, not a promise: yours will vary with your spot, shade and when you use power.

Ways to squeeze more out of it

The kit only saves you money on power your house uses while it's being made. So the trick is to shift jobs into daylight:

Put the washing machine on a delay timer so it runs at midday.
Same with the dishwasher, if it has one.
Damp terrace? Run the dehumidifier while the sun's out.
Slow cooker on in the morning, tea's ready by six.
Charge laptops, phones and the e-bike in the day.

Plug-in kits can't be used with a home battery, so daytime use is where the savings are.