The short answer
Yes. Solar panels work all year round in the UK, including in winter. They need daylight, not heat, so they keep generating electricity on cold, bright days and even when it is cloudy.
They do produce less in winter than in summer. The days are shorter, the sun sits lower in the sky, and there is more cloud. As a rough guide, a UK system generates around 25–35% of its yearly electricity between October and March, and the rest between April and September (Good Energy).
At Eco Systems Group, we have installed solar panels and battery storage since 2012, across London, the South East and the East of England. This guide explains what happens to your panels in winter, and how to get the most from them.
What winter does to your solar panels
Cold weather: not a problem
Solar panels don’t need warmth to work. In fact, they convert sunlight into electricity slightly more efficiently when they are cool, because heat reduces a panel’s performance. A crisp, clear winter’s day can be a surprisingly good day for generation.
Short days and a low sun: the main reason output falls
In December there are only around eight hours of daylight in the South East, compared with more than sixteen in June. The sun is also lower in the sky, so its light is weaker by the time it reaches your roof. This is the biggest reason winter output is lower.
Cloudy days: still generating
Panels still produce electricity under cloud, because daylight still reaches them. Output is lower than on a bright day, but it doesn’t stop.
Snow: usually clears quickly
A light covering of snow normally slides off panels within a day or two, helped by their angle and smooth glass surface. Don’t climb onto the roof to clear them; it isn’t safe, and you could scratch the glass.
Does roof direction matter more in winter?
Yes. South-facing roofs make the most of the low winter sun. East- and west-facing roofs still work well across the year, and we design every system around your roof at the survey.
How to get the most from solar in winter
Add a battery
In winter, most of your solar power is made in the middle of the day, when many people are out. A battery stores it for the evening instead of sending it to the grid for a few pence. We install Fox ESS, Sigenergy and Tesla Powerwall batteries, and most can be added to an existing system. Read our guide to adding a battery to your solar panels.
Charge your battery on a cheap overnight tariff
This is where a battery really earns its keep in winter. Many energy suppliers offer cheaper electricity overnight. Your battery can charge at the low rate and power your home through the expensive evening peak, topped up by whatever your panels make during the day.
Keep the heat in with insulation
The cheapest energy is the energy you don’t use. Good cavity wall and loft insulation means your home holds on to more of its heat, so every unit of electricity, from your panels or the grid, goes further. As one company for solar, battery and insulation, we can look at all three at the same survey.
Keep an eye on the app
Your system’s app shows what you are generating, storing and using. In winter it helps you run the washing machine or dishwasher in the middle of the day, when your panels are producing.
Frequently asked questions
Do solar panels work on cloudy days? Yes. They generate less than on a bright day, but they still produce electricity from daylight that passes through the cloud.
Do solar panels work in the snow? A thin layer of snow will block some light, but it usually slides off within a day or two. Panels generate again as soon as they clear.
Is it worth installing solar panels in winter? Yes. Installers are often less busy, and your system will be ready for the longer, brighter days of spring and summer, when most of the year’s electricity is made.
How much electricity do solar panels make in winter? Roughly a quarter to a third of a system’s yearly output is generated between October and March. The exact figure depends on your roof, its direction and shading.
Do I need a battery for winter? You don’t need one, but it helps. A battery stores daytime solar power for the evening and can charge on a cheaper overnight tariff, which is where much of the winter saving comes from.
Get a free solar survey
Thinking about solar panels or adding a battery? Call Eco Systems Group on 0203 411 4885, email info@ecosystemsgroup.co.uk, or request a free, no-obligation quote online. We cover London, the South East and the East of England, including Essex, Kent, Surrey and Norfolk.
