Wall output calculator

How much will your wall generate?

Pick a kit, the way your wall faces and how your household uses power. You get the sourced best case, the 10 and 20-year totals, and the kit that fits your wall.

Enter your wall

Kit

Where will the stand go?

On the wall On the ground, at 30°

Who's home in the day?

Clear wall space (metres)

Width

Height

Measure the patch clear of windows, vents and pipes.

Change the figures we use

Yearly generation for an 800W kit at 30°, facing south (kWh)

Your unit rate (pence per kWh)

Your estimate, explained

Best case for this kit (south, 30°, no shade)

around £180 a year

Generation, best case: 976 kWh a year
Used in your home: 70%
Over 10 years: around £1,760
Over 20 years: around £3,430
Carbon saved: about 90kg a year
Range, 40–70% used: £105–£180 a year
Your set-up: Being checked

See this kit

Inside the wall-output model

Every figure in the result comes from one of these. Where we don't have a source, the calculator says so.

Assumption	Figure we use	Source
Yearly generation, 800W kit	About 700 kWh, facing south at 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	Our estimate, from the Energy Saving Trust figure
Share 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	Ofgem price cap, announced 26 August 2026
10 and 20-year totals	Today's unit rate, panels losing 0.5% of output a year	Our assumption
Carbon	0.131kg CO2 per kWh of grid electricity	UK Government greenhouse gas conversion factors, 2026
Power sent to the grid	Counted as zero	Self-installed plug-in kits generally don't qualify for export payments
Wall directions and the steeper wall angle	Not modelled yet	Being checked against PVGIS, the European Commission's published solar model. No figure until it's checked
Kit space	The maker's stated space for each kit	The maker's datasheets, September 2026

Getting more from a wall kit

The biggest lever is when you use power. A south wall gets the sun through the middle of the day, so run the washing machine, dishwasher or tumble dryer then. East walls suit early risers and west walls suit afternoons and teatime.

Bigger panels help too. Each kit is capped at 799VA, but more panel power keeps a wall kit near that cap for longer as the sun moves across.

Why no figure for my east or west wall?

We only show figures we can source. We're checking each wall direction against PVGIS, the European Commission's published solar model, and will add them once they're checked. Until then, the best case is the top of the range.

Does the 800W limit matter on a wall?

Less than on the ground. An upright panel rarely hits its full rating, so the extra panel power in the bigger kits helps them get closer to the 799VA cap for more of the day.

Is my calculator data saved?

No. The calculator runs in your browser and sends nothing to us.