Plug-in solar
Plug-in and balcony solar calculator
An 800 W kit plugs into a socket, with no electrician and no roof. Tell us where it goes, which way it faces and what stands in front of it, and we work out what it would make, what it saves you and how fast it pays back.
Last updated 2 November 2026.
What would a plug-in kit make here?
Say where the kit goes, which way it faces and what stands in front of it. Add your postcode for your own area's sun.
Know the height and distance?
Estimated generation
560–690 kWh/year
2 panels (0.88 kWp), hung upright, facing south, open sky.
Bill saving
£95–£145
A year, with no export payment
Kit cost
£400–£800
Off the shelf
Payback
4–6yrs
Before it pays for itself
CO₂ saved
≈ 111kg
A year, against grid electricity
About 73%
of what the same panels would make on a pitched south roof. Upright panels miss the high summer sun.
About 41%
of its energy comes October to March, when the low sun hits an upright panel square on. A pitched roof: about 32%.
How that adds up
- Used at home, about 70%
- 390–480 kWh
- Given to the grid, the rest
- 170–210 kWh
- Bill savings
- £95–£145/yr
A plug-in kit has no export contract, so the power nobody is using at the moment it is made goes to the grid for free. Running the washing machine, the dishwasher or a laptop while the sun is up is what makes it pay.
Climate data from PVGIS for typical UK (Birmingham), on panels hung upright facing south with open sky. UK 2026 prices. Estimates to plan around, not a survey. How we measure.
Month by month
How an upright kit generates across the year. Flatter than a roof: the low winter sun suits it.
Most generation lands in the brighter months (highlighted). A system is sized for the whole year, not just summer. Estimated from PVGIS climate data for your postcode area — a roof survey confirms your exact figure.
Solar resource data: © European Union, 2025, PVGIS, EU Science Hub.
Before you buy
What to check on a plug-in kit.
- 800 W at the socket. A complete, factory-built kit up to 800 VA, no battery, with a moulded plug, is what the Great Britain rules allow since 27 August 2026. Look for UKCA or CE marking for the UK market.
- Tell your network operator. A G98 notification within 28 days of plugging in. It is a free form, and one plug-in kit per property.
- The socket. Outdoor-rated, on an RCD-protected circuit, and never an extension lead through a window.
- Stands and frames. Bolt or weigh down a garden stand against the wind, and check a flat roof or shed can carry the frame before it goes up.
- Fences and timber. In England a kit fixed to a wooden fence, balcony, gate or timber cladding has no permitted development rights, so it may need planning permission. Brick and render follow the ordinary solar rules.
- Whose wall it is. Leaseholders need the freeholder's or management company's written consent for the outside of the block; renters need the landlord's.
- No export payment. Without an MCS certificate the kit cannot join the Smart Export Guarantee, so run the day-time loads while the sun is up.
Want more than 800 W?
A wall-mounted array has no socket limit.
An MCS installer can fix a full array to a sunny wall, wire it to a proper inverter and sign you up for export payments. Size it from your wall space and see the listed installers covering your area.
How it works
What this calculator works out.
Generation where the kit sits
The sun on a panel at 90° (balcony, wall, fence) or 30° (stand) facing your direction, from the PVGIS climate record for your postcode area, with the sky in front blocked as high as you said, then the 800 W limit. Upright and south-facing, a kit makes about 70–75% of what it would on a pitched south roof; on a stand, close to all of it.
Shade
Whatever stands in front of the panels hides the low sun. Houses across a road take roughly a quarter off an upright south kit's output; a block of flats or tall trees close by, nearer half. Pick the nearest description or type the height and distance.
Saving
A plug-in kit saves only on the power something in the home is using as it is made, with nothing for the rest. After the sun itself, being home by day matters most.
Payback
Kit cost divided by the annual saving, as a range. A kit is cheap enough that a sunny spot pays back in a handful of years; a shaded or north-facing one may never.
The figures behind it
2026 assumptions.
Panels
440 W each, 1.134 m by 1.762 m
A standard retail module, the size most plug-in kits ship with.
Placement
Upright, or 30° on a stand
A balcony rail, house wall or fence holds the panels at 90°. A garden stand or flat-roof frame tilts them back, at the common retail angle.
Plug-in limit
800 W
The most a plug-in kit may put into a socket in Great Britain since 27 August 2026. Past two panels the microinverter clips the peaks, and the estimate takes that off.
Kit cost
£400–£800
A one- or two-panel kit with microinverter and mount, plus £150–£250 for each panel after that.
Electricity price
24–30p per kWh
Low end tracks the Ofgem price cap; high end covers non-direct-debit and regional spread.
Export payment
None
A plug-in kit has no MCS certificate, so it cannot join the Smart Export Guarantee.
Power used at home
50–85%
A kit this small sits under the fridge, router and standby load, so most of it is used as it is made. Set by how often you are home.
Shade
0°, 10°, 25° or 40° of sky blocked
How high what stands in front of the panels reaches above the horizon. Type a height and distance for your own figure. Applied across the sky the panels look at.
Grid carbon
0.177 kg CO₂ per kWh
UK electricity generation factor, DESNZ 2025.
Got a roof as well?
Check your own roof.
Enter your property number and postcode today, and we'll read your roof from the sky to get a better understanding of whether or not your roof is suitable for solar panels. Free, takes minutes, and no account necessary.
Common questions
Plug-in and balcony solar, answered.
How much does an 800 W plug-in solar kit make in the UK?
Two upright panels on a south-facing, unshaded balcony or wall come out at roughly 550–700 kWh a year in this calculator, depending on where in the country you are. The same kit tilted on a garden stand makes about a third more. East or west facing, expect around two-thirds of the south figure; behind two-storey houses, about a quarter less again. The tool shows the range for your own spot and area.
Is a plug-in kit better upright or tilted?
Tilted, if you have the space. In the Midlands a south-facing kit on a 30° garden stand makes about a third more over the year than the same kit hung upright on a balcony. Upright still earns its place: it takes no floor space, it sheds dirt, and its output is flatter across the year. Pick your placement in the calculator to compare the two.
Why do upright panels make more of their energy in winter?
An upright panel faces the low winter sun square on and catches the high summer sun at a glancing angle, so its output is flatter across the year than a pitched roof’s. In London a south wall makes around 40–45% of its energy between October and March, against about a third for a roof at 40°. It still makes less over the whole year, but more of it lands when bills are highest.
Do I get paid for the electricity a plug-in kit exports?
No. The Smart Export Guarantee needs an MCS certificate, which a plug-in kit does not have, so anything the kit makes while nothing in the home is drawing it goes to the grid for free. That is why the calculator asks when you are home. A wall-mounted array fitted by an MCS installer can join an export tariff like any rooftop system, and our wall-mounted solar calculator works that out.
Can I fit a plug-in panel to a fence, balcony rail or shed?
Yes, and that is where most kits go. In England a plug-in kit on a wooden fence, balcony, gate or any timber-clad part of a building is not permitted development, so it may need planning permission; on a brick or rendered wall it follows the same rules as other solar. Leaseholders need the freeholder’s consent for anything on the outside of the block, and renters the landlord’s. Check wind loading on an exposed balcony or stand.
Do I need an electrician or to tell anyone?
A complete kit of up to 800 W plugs into a normal socket under the rules in force since 27 August 2026, with no electrician. You still notify your network operator under G98 within 28 days, which is a free form. Use an outdoor-rated socket on an RCD-protected circuit, and keep to one plug-in kit per property.
Can I add more than two panels?
You can, but the 800 W limit is on the inverter, not the panels, so a third or fourth panel adds less than the first two: the peaks are clipped on bright days. The calculator takes that off for you. Past four panels you are into wall-mounted territory, where an MCS installer fits a proper inverter and you earn export income. Our wall-mounted solar calculator covers that.
