An 800W solar panel setup in the UK covers a broadband router, a laptop, a TV and a fridge’s average draw during daylight. It won’t cover a kettle, because 80% of measured UK kettle cycles peak above 1 kW. Modelled on a Manchester balcony, the kit’s best hour in five years averaged 653 watts.
That last figure is the one most buying guides skip. An 800 VA inverter is rated for 800 volt-amps, and the panels are rated at a laboratory peak. Neither is what arrives at your socket on a Tuesday in November. This page works out what 800W of solar delivers, using a method you can re-run, and puts common household appliances against it.
The short version
Modelled in PVGIS, 800 Wp hung vertically on a south-facing Manchester railing produces about 517 kWh a year. Across 43,824 modelled hours it never exceeded 653 W, and the median daylight hour was 67 W. The best hour of the day averages 310 W in April and 175 W in November. Anything the flat isn’t using goes to the grid, and earns nothing without an export arrangement.
An 800W kit doesn’t run appliances on its own
The word "run" is borrowed from a different kind of product. Much of the advice under 800W solar is written for 12V off-grid gear and portable power stations, where a battery holds energy and an inverter feeds a socket you plug into. In that world, asking what it runs makes sense.
A UK plug-in solar device works the other way round. It plugs into an existing socket and pushes its output back into the flat’s ring circuit, where it’s consumed by whatever happens to be switched on. There’s no store, and no separate socket. If generation is 200 W and the flat is drawing 320 W, the grid supplies the other 120 W and you don’t notice the handover. Our explainer on how plug-in solar panels work covers the mechanism.
So the useful question is how much of your consumption the kit offsets, and when. An appliance drawing less than the kit is making is fully covered, one drawing more is partly covered, and nothing switches off when a cloud passes.
How we worked out these output figures
Every output number here comes from PVGIS, the photovoltaic performance tool published by the European Commission’s Joint Research Centre, via its version 5.3 API in August 2026.
| Parameter | Value used |
|---|---|
| Location | Manchester, 53.48°N, 2.24°W |
| Databases | PVGIS-SARAH3 radiation, ERA5 meteo |
| Peak power | 0.8 kWp crystalline silicon |
| System loss | 14%, the PVGIS default |
| Slope | 90°, a vertical railing mount |
| Azimuth | 0° south, ±90° east and west |
| Mounting | Fixed, free-standing, DEM horizon |
| Hourly series | 2019 to 2023, 43,824 records per orientation |
Two runs, cross-checked. The PVcalc endpoint, which averages 2005 to 2023, returns 517 kWh a year. Averaging the hourly seriescalc output over 2019 to 2023 gives 515 kWh.
Four caveats, three of which push the real figure down. PVGIS models terrain, not the block opposite or the balcony slab above your head. It assumes a free-standing panel with air behind it, so one clamped flat against a railing runs hotter. The 14% loss allowance is generic rather than a measurement of any kit. And the hourly values are averages, so a brief peak can sit above the numbers below. Treat what follows as an optimistic ceiling. For a figure with your own postcode, our savings calculator runs the same estimate.
What an 800W kit actually produces
The modelled year for a vertical, south-facing 800 Wp array in Manchester. The last column is mean output in the best hour of the day, local clock time.
| Month | Average per day | Best hour of the day |
|---|---|---|
| January | 0.79 kWh | 151 W |
| February | 1.27 kWh | 197 W |
| March | 1.67 kWh | 242 W |
| April | 2.20 kWh | 310 W |
| May | 1.68 kWh | 227 W |
| June | 1.61 kWh | 222 W |
| July | 1.48 kWh | 198 W |
| August | 1.62 kWh | 218 W |
| September | 1.69 kWh | 238 W |
| October | 1.25 kWh | 199 W |
| November | 0.89 kWh | 175 W |
| December | 0.79 kWh | 164 W |
April beats June, which surprises people. A vertical panel points at the horizon, and in high summer the sun sits overhead and strikes the glass at a glancing angle. The same geometry is why November’s best hour is only about a fifth below June’s. What collapses in winter is the length of the day rather than the midday hour, the point our winter performance guide makes in detail.
Averages hide what matters, which is how the hours are distributed. Cloud cover and the sun’s angle mean most daylight hours produce very little:
- Highest single hour in 43,824 modelled hours: 653 W
- Hours above 600 W: 4 a year
- Hours above 400 W: 279 a year
- Hours above 200 W: 987 a year
- Hours above 100 W: 1,670 a year
- Median daylight hour: 67 W
Across five modelled years the array never produced 800 W in any hour. Averaged over a full November day, night included, output comes to about 37 W. And 517 kWh from 0.8 kWp is 646 kWh per kWp, the equivalent of 1.77 peak sun hours a day.
Appliance by appliance
The energy use figures below come from the Household Electricity Survey, an appliance-level study of 251 English households run for DEFRA, DECC and the Energy Saving Trust between May 2010 and July 2011, published on gov.uk as Intertek report R66141. It’s fifteen years old, and today’s products are more energy-efficient, so read the low figures as conservative.
| Appliance | Measured draw | Best hour in June, 222 W | Best hour in November, 175 W | A whole December day, 0.79 kWh |
|---|---|---|---|---|
| Broadband router | 11.5 W | Covered | Covered | 2.9 days of it |
| Refrigerator | 162 kWh/yr, about 18 W | Covered | Covered | 1.8 days of it |
| Set-top box | 19.8 W | Covered | Covered | 40 hours |
| Laptop | 32.3 W | Covered | Covered | 24 hours |
| Upright freezer | 35–40 W | Covered | Covered | 88% of a day |
| Fridge-freezer | 427 kWh/yr, about 49 W | Covered | Covered | 68% of a day |
| Desktop computer | 67.2 W | Covered | Covered | 12 hours |
| Television | 96.9 W | Covered | Covered | 8 hours |
| Washing machine | 0.58 kWh per cycle | Partly | Partly | 1.4 cycles |
| Portable air conditioner | Typically 1,000–1,200 W, range 700–2,500 W | No | No | No |
| Electric heater | Typically 1.5–3.0 kW | No | No | No |
| Kettle | 40% of cycles peak above 2 kW | No | No | 4 boils’ energy |
The two rows without a figure are the two we have no measured UK data for. The array’s highest modelled hour in five years was 653 W, so anything rated above that is out of reach even at the annual peak.
The always-on end of that list is where a plug-in kit earns its keep. A broadband hub, a set-top box and a fridge-freezer together sit near 80 W, and the array clears 80 W for roughly 1,870 hours a year, which is what suits a plug-in device to base load.
The kettle is the clean no, and it stands for most kitchen appliances. Measured across real households, 80% of kettle cycles peaked above 1 kW and 40% above 2 kW, against a device whose ceiling is 800 VA and 3.5 A. A boil is short, so 98% of measured cycles used under 0.2 kWh. The problem is the rate rather than the total, which also rules out a tumble dryer, a hair dryer and anything else that turns electricity into heat in a hurry.
The washing machine sits in between. Half of measured cycles used under 0.5 kWh and 90% under 1 kWh, so a whole December day’s generation is roughly one wash. During the heating phase it draws far more than the kit is making and the grid tops up the difference, but running it at midday shifts a real slice of the cycle onto your own panels.
Check the rating plate, not the marketing
Every appliance carries a rating plate, or a moulded label on its power supply, giving its power in watts or its current in amps. That’s the number to compare against the figures above, and it beats any generic table including ours. Because everything plugs into a BS 1363 socket on a 13 A fuse, nothing can lawfully draw much beyond 3 kW through one plug.
Output swings by the hour and by the compass
Two identical kits on one building can produce very different shapes of output. Same 800 Wp, vertical, Manchester:
| Orientation | Annual output | Best hour in June | Best hour in November |
|---|---|---|---|
| South | 517 kWh | 222 W at 12:00 | 175 W at 11:00 |
| East | 370 kWh | 250 W at 09:00 | 81 W at 10:00 |
| West | 357 kWh | 237 W at 17:00 | 65 W at 14:00 |
East and west both peak higher than south in June and then fall away sharply by November, because a vertical surface facing sideways catches the low winter sun at a glancing angle for a short window. About 67% of the south-facing array’s generation lands between 10:00 and 15:00 UTC.
Which shape suits you depends on when you’re at home. A west-facing kit puts its output into the late afternoon, when most households start using electricity in earnest. Our guide to the best direction for balcony solar covers all eight compass points. Location matters too: the same array models at 594 kWh in London, 636 kWh in Plymouth and 546 kWh in Edinburgh.
What happens to the electricity you don’t use
This is the part that decides whether an 800W kit is worth having, and it gets very little attention. Solar power the flat isn’t consuming flows out through the meter to the grid. Take a steady 150 W background draw. Against the modelled Manchester output, 196 kWh of the year’s 517 kWh, about 38%, would be surplus. Drop it to 100 W and the surplus rises to 52%. Put a constant 49 W fridge-freezer load against the same array and the kit supplies only about 146 kWh of that appliance’s 427 kWh year, because the fridge runs through the night.
Exported units earn nothing unless you have an export arrangement with a supplier. Most Smart Export Guarantee tariffs are gated behind MCS certification or an equivalent scheme, which a self-installed kit won’t have. Routes that don’t require MCS exist, with their own paperwork, fees and conditions, so our SEG tariffs guide is the place to check. At these volumes the payment is small regardless.
The obvious fix is battery storage, and the plug-in route doesn’t allow it. That exclusion is statutory rather than a clause in the specification, and our guide to why battery kits are excluded sets out the mechanism. Timing is the lever you’re left with. Run the washing machine and the dishwasher at midday instead of 19:00 and you convert excess power into savings. Our self-consumption guide covers how far that gets you.
Panel wattage: what 200W, 600W and 2,000W deliver
Output scales almost exactly with panel wattage until the inverter’s ceiling gets involved, so a smaller solar system produces proportionally less. Each figure queried separately rather than scaled:
| DC panel wattage | Annual output |
|---|---|
| 200 Wp | 129 kWh |
| 400 Wp | 259 kWh |
| 600 Wp | 388 kWh |
| 800 Wp | 517 kWh |
| 1,000 Wp | 646 kWh |
Going the other way, the specification caps AC power output at 800 VA but allows up to 2,000 W of DC panels behind it, with no more than four modules, no more than two in series, and open-circuit voltage at the inverter inputs no higher than 120 V DC. Clipping only shows up hour by hour, so this table uses the hourly series, which is why the 800 Wp row reads 515 kWh rather than 517:
| DC panel capacity | Annual output | Hours a year clipped |
|---|---|---|
| 800 Wp | 515 kWh | 0 |
| 1,200 Wp | 771 kWh | 48 |
| 1,600 Wp | 987 kWh | 279 |
| 2,000 Wp | 1,155 kWh | 512 |
At 2,000 Wp the inverter throws away about 10% of what the panels make and still delivers more than twice the output of an 800 Wp array. Extra panels mostly buy generation in the dim hours that make up most of a British year, and those never trouble the inverter’s ceiling. Above 960 W of panels the manufacturer must advise you to consider a professional assessment of your wiring. That’s an advisory rather than a limit, and crossing it isn’t a compliance failure.
Where this sits in the UK rules
From 27 August 2026 a compliant plug-in solar device can lawfully be sold and used in Great Britain, under SI 2026 No. 848. Before then the route doesn’t exist, and our page on whether balcony solar is legal in the UK explains why.
Two things to keep in view. G98 Issue 2 Amendment 1 2026 restricts a household to one device, whatever the specification permits per circuit, so the figures above are the whole of what one home can generate this way. And notification to your network operator is mandatory, with the simplified route still in development.
Nothing is verified compliant yet
Compliance turns on a verified ENA Type Test Register listing plus an on-product IPS declaration. At our last check on 11 August 2026 there were four entries under the plug-in solar device type, all assessed Non-compliant, leaving zero verified compliant devices. Non-compliant is a holding status rather than a refusal, and they’ll be reviewed again. It does mean there’s nothing on sale yet whose output you could measure against the model above.
Frequently asked questions
What can be powered with 800 watts of solar? In UK conditions a plug-in kit’s realistic midday output is closer to 175 to 250 W than to 800 W. That covers a broadband hub, a set-top box, a laptop, a television and a fridge’s average draw. It doesn’t cover a kettle, and anything whose rating plate reads above 653 W, the array’s best modelled hour, is beyond it as well.
Is 800W of solar enough power for a flat? Not close to a flat’s whole demand. Households in the Household Electricity Survey averaged 3,567 kWh a year against a modelled 517 kWh from a vertical 800 Wp array, roughly 15%, and only the part you’re at home to use.
How much power does an 800W solar panel produce in the UK? Modelled in PVGIS, 800 Wp mounted vertically and facing south in Manchester produces about 517 kWh a year, roughly 1.4 kWh a day. December and January average 0.79 kWh a day and April 2.20 kWh.
Why does an 800W system never produce 800 watts? The 800 W rating is the panels’ output under laboratory conditions of 1,000 W per square metre at 25°C, which UK weather rarely supplies, and a vertical mounting is far from the angle those tests assume. Across 43,824 modelled hours our array peaked at 653 W and spent four hours a year above 600 W.
Can an 800W solar panel run a fridge? In daylight, yes, in the sense that it covers a fridge’s average draw. A fridge-freezer in the Household Electricity Survey averaged about 49 W. The catch is that fridges run overnight too, so an 800 Wp array supplies only around a third of one’s annual consumption.
Is an 800W solar kit worth it in the UK? It depends on how much of the output you use rather than export. The government’s estimate of £70 to £110 a year models a 30° south-facing installation at its top end, and a near-vertical balcony sits at the bottom of that range. Running high-consumption appliances at midday is what moves the figure.
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