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SolarDo solar panels work in winter? Yes, just less than summer
Yes, solar panels work through a UK winter. They run on light, not on sunshine, so shorter days and more cloud reduce output rather than stopping it. The harder question is what orientation does to the value of each unit you generate, and how a system should be sized around it.
Updated 4 August 2026 · written by the Clearline guidance team
The short answer
Yes, solar panels work in winter. They generate in proportion to the light intensity reaching them, so shorter days and more cloud reduce output rather than switching it off. A grey British afternoon is not an off switch, it is a dimmer. The same logic applies to a north facing pitch: it generates, it simply generates less than the south facing pitch on the same house.
Cloud turns panels down, it does not switch them off
Output tracks the light that lands on the glass. Bright overcast still produces meaningful electricity, a black storm front produces very little, and the annual generation figure on a proper quote already assumes a normal British mix of both.
- Module efficiency
- 23.5 per cent at standard test conditions
- Power at NOCT
- 403 W
Diffuse light is still light
On a clear day most of the light hitting a roof arrives straight from the sun. On an overcast day that light is scattered by cloud and arrives from across the whole sky instead. A panel does not care which route the light took. It responds to how much energy lands on the cell, which is why a bright overcast day can still be productive and a dark one is not.
This is also why the headline rating on your quote is a laboratory number. kWp, or kilowatt peak, is measured under standard test conditions that include a 25C cell temperature. It is a fair yardstick for comparing one panel or one system against another. It is not a promise of what your roof delivers on a Tuesday in February. If the basics are new to you, start with how solar panels work.
Bright and cool beats bright and hot
Every panel datasheet carries a temperature coefficient and it is negative. The REC Alpha Pure-RX is quoted at -0.24% per degree, the Longi Hi-MO X10 at -0.26% per degree and the Jinko Tiger Neo platform at -0.29% per degree. Hotter cells means slightly lower output, so a crisp bright day outperforms a muggy one on the same roof.
The inverter decides how early your system wakes up
Low light performance is partly a wiring decision, not just a weather one. Most UK systems carry more panel capacity than inverter capacity, with a DC to AC ratio typically between 1.10 and 1.30 and most designs landing between 1.15 and 1.25. A modestly sized inverter starts generating earlier in weak light and keeps going later, and because panel ratings assume 25C test conditions that British roofs rarely sustain, the windows where the inverter caps output are short. Extra panels also lift morning, evening and winter yield, which is exactly when a cloudy climate needs the help. The full trade off sits in inverter sizing explained.
| What changes | Direction of travel | Why |
|---|---|---|
| Overcast sky | Down, not off | Output follows the light landing on the panel, and cloud scatters light rather than removing it |
| Winter | Down | Shorter days and a lower sun angle, which is normal and already inside the annual figure |
| Hot cells | Slightly down | Datasheet temperature coefficients are negative, typically -0.24% to -0.29% per degree |
| North facing pitch | Down | Direct sun reaches it only briefly around midsummer mornings and evenings, so it works mainly on scattered light |
| East and west split | Flatter rather than uniformly lower | Generation spreads across morning and afternoon instead of concentrating around midday |
| Shade across one panel | Depends on the wiring | A plain series string performs at the level of its weakest panel |
Temperature coefficients taken from manufacturer datasheets for REC Alpha Pure-RX, Longi Hi-MO X10 and Jinko Tiger Neo, accessed August 2026.
South, east, west, north: what orientation really changes
South facing collects the most over a year because it faces the sun through the middle of the day. An east and west split collects less at the peak but spreads generation across breakfast and late afternoon. North facing is the weakest of the four because it sees direct sun only at the edges of a midsummer day and otherwise runs on scattered light.
Total generation is only half of the calculation. What matters to your bill is how many units you use yourself rather than export. A unit you consume replaces one you would have bought, and the Ofgem cap for 1 July to 30 September 2026 puts the average capped electricity rate at 26.11p per kWh on direct debit. A unit you export earns your export rate, and Outgoing Octopus paid 12p per kWh flat when supplier pages were checked on 3 August 2026. Solar alone typically sees around 25% to 30% of generation self consumed, and adding storage lifts that to roughly 70% to 85%. An east and west roof that generates while you are actually awake and using power can therefore beat a south roof whose midday peak goes straight out to the grid. Our battery storage guide and tariffs guide cover both sides of that.
Clearline does not publish a single national percentage for what a north facing roof loses. The honest number depends on your latitude, pitch, orientation and shading, and it comes out of a design model rather than a rule of thumb. Every county page carries a calculator built for that area, so put your own roof into your county page rather than taking an average.
A free design call runs your actual pitch, orientation and usage through the model and gives you a figure for your house instead of a national average.
Get your free quote →Pitch, flat roofs and the shading question
Pitch decides the angle at which light strikes the panel, so it interacts with orientation rather than acting on its own. A steeper pitch favours the low winter sun and penalises a north facing aspect more heavily. A shallower pitch behaves more like a flat surface, which softens the orientation penalty because a horizontal panel faces no direction in particular. Flat roofs are usually fitted on frames precisely so the angle can be chosen rather than inherited.
- On a pitched roof, permitted development limits mean panels must not sit above the highest part of the roof excluding the chimney, and must project no more than 200mm from the roof plane.
- On a flat roof, the highest part of the equipment cannot exceed 600mm above the highest part of the roof, which caps how steeply a frame can be tilted.
- Shade is a separate problem from orientation, and it is a wiring problem first. Panel level electronics such as optimisers or microinverters stop one shaded module dragging the rest of a string, and some modern back contact panels bypass shaded cells within the module itself.
- Optimisers can be deployed selectively on the affected panels only, so a partly shaded roof does not automatically mean paying for module level kit across the whole array. The answer is genuinely different for a clean single aspect roof and a chimney shaded multi aspect one, and we set out the triage in microinverters versus optimisers versus string inverters.
What all this means for sizing
- Treat cloud as already priced in. A credible annual generation figure assumes British weather, so discount the quote that promises otherwise, not the technology.
- Size against your usage pattern, not just the compass. Electricity generated while you are home is worth 26.11p, electricity exported is worth your export rate, and that gap decides the design.
- Do not write off a north facing or awkward pitch before it is modelled. It may still stack up once storage and export are in the picture, and it may not. Both answers are useful.
- Fill the roof you are already paying to scaffold. Scaffolding runs around 13% of a typical solar install cost and it goes up once, so marginal panels are the cheapest capacity you will ever buy.
- Get the shading answer before the kit answer, because it changes which inverter architecture is worth paying for.
- Put your postcode into the calculator on your county page for a local starting point before you speak to anyone.
Twenty minutes on video, your roof on the screen, and a straight answer on whether that north pitch is worth panelling. Installations are carried out by an MCS-certified installation team for your area.
Get your free quote →Cloudy days and awkward roofs, answered
Do solar panels work in winter?
Yes. Panels generate in proportion to the light intensity reaching them, so shorter winter days and more cloud reduce output rather than stopping it. Bright overcast conditions still produce a useful amount, heavy dark cloud produces very little, and a properly modelled annual generation figure already assumes a normal British mix of weather, winter included, rather than continuous sunshine.
Are north facing solar panels ever worth it?
Sometimes, and it depends on the whole design rather than the compass alone. A north facing pitch sees direct sun only at the margins of a midsummer day and otherwise runs on scattered light, so it generates least of the four aspects. Whether it pays depends on your pitch, your shading, how much you use during daylight and what your export rate is. Model it before ruling it out.
Is an east and west roof worse than a south facing one?
It usually generates less across a year, but it does not always save less. An east and west split spreads generation into the morning and late afternoon rather than concentrating it at midday, which can line up better with when a household is actually at home. Because a unit you use yourself is worth 26.11p against the July to September 2026 capped average, and an exported unit is worth your export rate, the timing matters as much as the total.
Does roof pitch matter as much as direction?
It matters, and the two interact. A steeper pitch favours the low winter sun and makes a north facing aspect worse, while a shallower pitch behaves more like a horizontal surface and softens the orientation penalty. Flat roofs are normally fitted on frames so the tilt can be chosen, subject to the permitted development limit of 600mm above the highest part of the roof.
Do I need optimisers if my roof is shaded or faces the wrong way?
Shading and orientation are different problems. Orientation lowers the light reaching every panel evenly, which no electronics can fix. Shading affects some panels and not others, and that is where optimisers or microinverters earn their money by stopping one shaded module dragging a whole series string. Optimisers can be fitted selectively to only the affected panels, and some back contact panels already bypass shaded cells inside the module.
Does cold weather damage solar output?
No, cold slightly helps. Panel datasheets carry negative temperature coefficients, typically between -0.24% and -0.29% per degree, so output falls a little as cells heat up and improves a little as they cool. Winter generation is lower because the days are shorter and the sun sits lower, not because of the temperature.
See the numbers next: LONGi 530 W panels, installed, or the solar panels guide.
Figures and specifications in this guide are sourced below and were checked on the date shown. Rates and product specifications change; we confirm the current picture on your free design call.
Sources
- Panels generate in proportion to light intensity, so they still produce on cloudy days and in winter sunsave.energy
- REC Alpha Pure-RX datasheet, temperature coefficient -0.24% per degree recgroup.com
- Longi Hi-MO X10 module specification, temperature coefficient -0.26% per degree qualityheating.co.uk
- Jinko Tiger Neo platform specification, temperature coefficient -0.29% per degree jinkosolar.com
- DC to AC ratio norms of 1.10 to 1.30, with most systems between 1.15 and 1.25, and how clipping works aurorasolar.com
- UK clipping windows, 25C test conditions and why a smaller inverter starts generating earlier in low light spiritenergy.co.uk
- Array oversizing relative to the inverter lifts morning, evening and winter yield freedomforever.com
- Self consumption of roughly 25 to 30% on solar alone, rising to 70 to 85% with a battery solarthermuk.co.uk
- Ofgem energy price cap, 1 July to 30 September 2026: 26.11p per kWh electricity average on direct debit ofgem.gov.uk
- Outgoing Octopus flat export rate of 12p per kWh, supplier page checked 3 August 2026 octopus.energy
- Permitted development limits for roof mounted solar, 200mm projection on a pitched roof and 600mm on a flat roof planningportal.co.uk
- How series strings, power optimisers and microinverters handle partial shading energysage.com
- Longi Hi-MO X10 cell level shading bypass design solenenergy.com
- Tigo TS4-A-O selective optimiser deployment on affected panels only tigoenergy.com
- Scaffolding at around 13% of a typical UK solar installation cost spartek.co.uk
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