What will an 800W plug-in solar kit actually run?
An 800W plug-in solar kit will not power your house. What it will do is cover the devices humming away in the background all day, the ones you never think about, and take a slice off your bill for doing it. This guide puts real numbers on what that means in a UK home.
The short answer
On a bright day an 800W kit comfortably covers your fridge, router, a few LED lights, a laptop and a phone charger, all at once. Add it up: a 150W fridge, a 20W router, a 50W laptop and three 10W bulbs comes to about 250W, well inside the kit's ceiling with room for a TV on top.
Switch on a 3kW kettle or an 8.5kW electric shower and you are instantly past what the panels can supply. Nothing breaks. The grid quietly makes up the difference, exactly as it did before.
Now legal to plug in. Socket connection became lawful in England, Wales and Scotland on 27 August 2026. A certified kit goes straight into a fixed BS 1363 socket, no electrician needed, and you notify your DNO under G98 within 28 days. Full detail in the plug-in solar legality guide.
Over a year, a well-sited 800W kit makes somewhere between 550 and 860kWh. Ofgem's medium household now uses 2,500kWh of electricity a year, so the kit generates the equivalent of roughly a quarter to a third of your annual use. The share you actually save on is smaller, because you only benefit from what you use as it is being made. In practice that is nearer 15–20% of the bill.
Which makes this a bill-trimming exercise, not a route off the grid. How much you get out of it depends less on the panels than on who is home during the day and what is switched on.
How much energy it actually makes
Worth separating two numbers that get muddled. 800W is the most the inverter can push out at any instant, like a car's top speed. kWh is energy over time, and it is the only one that appears on your bill.
In June and July an 800W kit produces roughly 2.5–4.0kWh a day. In December a grey day might not clear 0.5kWh. Over the year, for a south-facing kit at a sensible tilt:
| Region | Estimated annual output |
|---|---|
| South-East England | 700–800kWh |
| Midlands | 650–750kWh |
| Northern England | 620–740kWh |
| Scotland | 570–690kWh |
For scale: boiling a kettle uses about 0.25kWh, a washing machine cycle roughly 1.5kWh, and a fridge-freezer gets through 1–2kWh a day. So 3–4kWh on a good summer day runs the fridge from morning to night, charges the laptop, and still leaves something over.
Those regional figures assume a decent tilt. A kit clamped near-vertical to a balcony railing gives up 20–30% against an angled mount, which is why a real balcony installation often lands at 550–650kWh rather than 800. More on that below.
What it can and can't run
A plug-in kit doesn't wire to a particular appliance. It pushes solar into your home's circuits, and whatever is drawing power at that moment takes it before the grid gets a look in. So the useful question is not "can it run my fridge" but "what is my house drawing right now, and is it under 800W".
A typical daytime load sits well inside 800W. Anything that heats water or air does not.
Covered comfortably:
| Appliance | Typical draw | In practice |
|---|---|---|
| Fridge-freezer | 100–200W | Cycles on and off; the kit covers it either way |
| Broadband router | 10–20W | Runs on solar all day, every sunny day |
| LED lights | 5–10W each | A whole room's worth barely registers |
| Laptop and monitor | 50–120W | A full working day, comfortably |
| Television | 60–120W | Daytime viewing covered |
| Phone and tablet chargers | Under 10W | Rounding error |
Partly offset, grid tops up the rest: washing machines (800–2,000W at the heating stage), dishwashers, microwaves and toasters. The kit contributes what it can and you import the difference.
Beyond it entirely: electric showers (7–10kW), ovens and hobs (2–4kW), tumble dryers (2–3kW), EV chargers (2–7kW), fan heaters (1–3kW). Anything whose job is to make heat is in a different weight class.
Background load: where it earns its keep
Background load is the electricity your home draws whether or not anyone is doing anything: things that are always on, or cycling on a timer.
- Fridge-freezer: 100–200W when the compressor runs
- Router and modem: 10–20W
- Smart speakers, TV standby, alarm system: 10–30W between them
- A NAS drive or an always-on PC: 30–80W
- Aquarium pump or similar: 10–50W
In most homes that totals 150–300W, running all day. An 800W kit swallows it whole in decent sun with capacity left over.
The arithmetic is simple. A 200W background load across five strong hours of sun is 1kWh you didn't buy. Do that most days from April to September and it adds up.
Which is why households with more running in the background get more from a kit. A home office, a second fridge in the garage, a heat pump ticking over low and steady: all of it soaks up solar that would otherwise leave the house for nothing.
Three real days in a UK home
Working from home. Laptop and monitor around 120W, a couple of lights at 20W, router at 15W, fridge at 120W. Call it 275W. On a sunny summer day the kit makes 4–5kWh across eight hours while your desk-and-background load uses about 2.2kWh. The spare covers a microwave lunch or a midday washing machine cycle. Dinner and the evening shower still come off the grid.
House empty nine to five. Fridge at 120W, router at 15W, a handful of standby devices. Around 150W, or 1.2kWh across the daylight hours. If the kit makes 4kWh, under a third of it gets used and the rest leaves the house. This is the case where timers earn their money.
Evening cooking and TV. Production stopped at sunset. The oven at 2–3kW, the hob, the lights and the telly all come from the grid. Without a battery the kit contributes nothing to the busiest part of your electrical day.
The pattern across all three: plug-in solar shaves your daytime imports. Your smart meter won't show a "solar" line. It will just show you buying less between about 10am and 4pm.
What seasons, weather and placement do to it
800W is a ceiling, not a promise. Panels hit their rated output under test conditions, and UK weather is not test conditions.
- Season. A south-facing kit may touch 700–800W at midday in June. The same kit in December might peak at 150–250W, across far fewer hours.
- Orientation. South is best. East or west costs you roughly 10–25% over the year. North is rarely worth the money.
- Shading. Trees, neighbouring buildings, even the railing itself. With two panels on one inverter, shade on one can drag down the pair, not just the shaded panel.
- Mounting angle. A near-vertical balcony mount delivers roughly 70–80% of what the same panels would make at a 30–40° tilt on a shed roof or garden frame.
Stack the good version against the realistic one and the gap is wide. A south-facing garden mount at 30°, unshaded, can reach 800kWh a year. The same kit clamped flat to a partly shaded balcony rail is more likely to land at 550–650kWh. That is the difference between covering your fridge for eleven months of the year and covering it for seven.
What happens to the electricity you don't use
Your appliances take the solar first. Anything left over flows out through the meter to the local network.
You will not be paid for it. Smart Export Guarantee payments require an MCS-certified installation, and a self-installed plug-in kit cannot be MCS certified. Exported units are a gift to the grid.
This is why self-consumption matters more than raw output. Generate 700kWh but use only 60% of it yourself and just 420kWh saves you anything. Push that to 80% and you have gained 140kWh without buying a single extra panel.
A battery would solve this, and mostly it can't. Certified kits arriving for the new rules are deliberately panels-only, because the legal definition of a plug-in microgenerator excludes anything designed to import electricity from your installation to store for later. Any battery has to be a separate product on its own circuit. We go into the detail in the plug-in solar and batteries guide.
What it saves
At the July–September 2026 price cap rate of 26.11p per kWh, the sum is straightforward: annual output, multiplied by the share you use yourself, multiplied by the unit rate.
| Situation | Output | Self-consumption | Annual saving |
|---|---|---|---|
| London, garden mount, someone home most days | 780kWh | 70% | ~£143 |
| Midlands, tilted balcony, mixed occupancy | 680kWh | 60% | ~£107 |
| Manchester, vertical rail, empty weekdays | 580kWh | 45% | ~£68 |
So £70 to £150 a year, with placement and occupancy deciding where you land in that range. To make it tangible, £100–£130 covers roughly a year of running your fridge, router and television.
An 800W kit costs around £500, with the range running £400 to £1,000 depending on panels and mounting hardware. At £100 a year that is a five-to-seven year payback. Poor placement or an empty house stretches it towards eight or ten.
One more thing that catches people: the 0% VAT rate on solar applies to supply-and-install packages from a single contractor. Buy a kit off the shelf and fit it yourself and you pay the standard 20%.
Browse our UK plug-in solar range, sized for balconies, patios and small gardens.
800W plug-in versus a full rooftop system
| 800W plug-in kit | Full rooftop system | |
|---|---|---|
| Typical size | One or two panels, 800W inverter | 10–14 panels, 3–5kW |
| Annual generation | 550–860kWh | 3,000–4,200kWh |
| Upfront cost | £400–£1,000 | £6,000+ |
| Installation | DIY since 27 Aug 2026 | MCS installer, survey, scaffolding |
| Export payments | None | Eligible for SEG |
| Annual saving | £70–£150 | £470–£650+ |
| Battery pairing | Separate circuit only | Straightforward |
| Take it with you | Yes | No |
A rooftop array makes five to eight times as much and gets paid for the surplus. If you own a house with a usable south-facing roof and you intend to stay, that is the better investment and it isn't close.
Plug-in is for the people that maths excludes: flats, rentals, no roof access, or a budget that doesn't stretch to five figures. About 19% of English homes are flats, and in London it is closer to half.
When it makes sense, and when it doesn't
Worth doing when:
- You rent or live in a flat with a sunny balcony, and a roof array was never an option.
- Someone is home during the day, or you work from home.
- Your background load is on the higher side: home office kit, a second fridge, a home server.
- You want to spend a few hundred pounds rather than several thousand.
- You have a shed roof, garden wall or patio that gets real sun.
Think again when:
- You have good, unshaded roof space. Get rooftop quotes first.
- You are hoping to run electric heating, a heat pump or an EV from solar. 800W is nowhere near.
- Your wiring is old, the consumer unit is unlabelled, or the sockets are in poor condition. Get an electrician to look before anything is plugged in.
- The only spot you have faces north or sits in shade for half the day.
Three practical things to check before you order: what the railing can take in a gale and what your building's rules say about it; whether a cable can reach a fixed wall socket, because extension leads and multi-way adaptors are prohibited; and whether your landlord, freeholder or managing agent will consent to brackets on the exterior.
The 2026 UK rules in brief
Plugging a generator into a normal socket was not permitted in Great Britain for years. That changed on 27 August 2026, when SI 2026 No. 848 came into force. Since that date a certified kit of up to 800W AC may be connected through a standard BS 1363 socket without an electrician.
- The kit must meet the Plug-in Solar Device Interim Product Specification, version 2, and the inverter must appear on the ENA G98 Type Test Register.
- 800W is the AC ceiling. Up to 2000W of panel DC is allowed behind it.
- Anti-islanding is mandatory, so the inverter drops out in a power cut rather than backfeeding the network.
- One plug-in device per household, not per circuit.
- Direct into a fixed socket. No extension leads, multi-way adaptors, travel adaptors or RCD adaptors.
- G98 notification to your Distribution Network Operator stays mandatory, within 28 days of switching on.
- Kits with an integrated grid-charging battery fall outside the definition and need hard-wiring by an electrician.
- Regulation 3 extends to England, Wales and Scotland only. Northern Ireland is not covered.
On insurance: tell your provider, and be wary of uncertified kit. A non-compliant DIY connection is exactly the sort of thing that gets picked over after an electrical fire claim. The balcony solar guide covers permissions, prohibited mounting surfaces and the notification process in full.
800W plug-in solar: your questions answered
Can an 800W kit run my fridge?
Yes, easily. A modern fridge-freezer draws 100–200W when the compressor is running and uses 1–2kWh a day, well inside what an 800W kit produces on any reasonable day between spring and autumn.
Will it run a kettle or a washing machine?
Not a kettle: at 3,000W it needs nearly four times the kit's output, so almost all of it comes from the grid. A washing machine is partly covered — the kit offsets a chunk of the 800–2,000W heating stage and most of the lower-power tumble and spin.
How much will an 800W kit save me a year?
Between about £70 and £150 at the July–September 2026 cap rate of 26.11p per kWh. Where you land depends on output and on how much you use as it is generated. Good placement plus someone home during the day pushes you to the top of that range.
Do I get paid for the electricity I don't use?
No. The Smart Export Guarantee requires an MCS-certified installation, which a self-installed plug-in kit cannot have. Surplus goes to the grid for nothing, which is why it pays to use what you make rather than to oversize.
Can I add a battery to store the surplus?
Not inside the plug-in kit. The legal definition excludes devices designed to import electricity for later storage, so certified kits are panels-only. A battery has to be a separate product on its own circuit, professionally installed.
What percentage of my electricity bill will it cover?
An 800W kit generates the equivalent of roughly a quarter to a third of a medium UK household's 2,500kWh annual use, but you only save on what you consume directly. Realistically that is 15–20% of your electricity bill.
Do I need to tell anyone I've installed one?
Yes. G98 notification to your Distribution Network Operator is mandatory within 28 days of commissioning, even for a plug-in kit. It is a short online form, not an approval process. Our G98 and G99 guide walks through it.
An 800W kit is a small, honest piece of equipment. It will not rebuild your relationship with the grid, but it will run the quiet half of your house through the daylight hours for the next twenty years, and it will come with you when you move. Work out which way your outdoor space faces, add up what you leave running during the day, and look for certified kits now the rules are live.