Do Solar Panels Work in Winter? What Surrey Homeowners Can Expect

As the clocks go back and the mornings turn grey, one question lands in our inbox more than any other: do solar panels actually work in winter?

It's a fair worry. If you're thinking about investing in solar, you want to know it will pull its weight all year, not just in July. In this post, I'll explain what really happens to your panels between November and February, how much power you can expect from a typical Surrey home, and how to make the most of the darker months.

The Short Answer: Yes, Solar Panels Work in Winter

Solar panels run on daylight, not heat. As long as there's light reaching the roof, your panels are generating electricity, even on a cold, overcast day.

In fact, cold weather can help. Solar panels lose a little efficiency as they heat up, which is why a crisp, bright January day can produce surprisingly strong output for the amount of sun available. A scorching summer afternoon is actually less efficient per hour of sunshine.

What changes in winter isn't how well the panels work, but how much light they get. Days are shorter, the sun sits lower in the sky, and cloud cover is more frequent. That means less total generation, but certainly not zero.

How Much Power Will My Panels Make in Winter?

As a rough guide, a typical 4kW south-facing system in Surrey might generate around 3,500 to 3,900 kWh over a full year. But that output isn't spread evenly.

• Summer months (May to August): often 400 to 500 kWh a month

• Winter months (November to February): more like 80 to 150 kWh a month

So in the depths of December, you might produce around a quarter of what you'd get in June. That still covers a meaningful chunk of daytime use, such as your fridge, freezer, broadband, lighting and a wash cycle or two.

The key thing to remember is that solar savings are calculated over a whole year. The long, bright summer days do the heavy lifting, and winter adds a smaller but steady contribution. Every installer quoting you should base their savings estimate on annual figures, not a single season.

These figures are approximate. Your actual output depends on your roof direction, pitch, shading and system size, which is exactly what a proper site survey works out.

What About Snow, Frost and Fog?

Snow: A heavy covering will stop generation until it clears, but in Surrey that's rare and short-lived. Panels are smooth, angled and slightly warmer than the roof around them, so snow usually slides off within a day or two. Please never climb onto the roof or use a hose to clear them. It's dangerous and can damage the glass.

Frost: A light frost melts quickly once the sun is up. Clear, frosty mornings are often some of the best winter generating days.

Fog and heavy cloud: Output drops, but diffuse light still gets through. Modern panels are designed to capture this scattered light, so a dull day still produces some power.

Short days: In December, Surrey gets roughly eight hours of daylight compared with over sixteen in June. Fewer hours of light is the main reason winter output is lower.

Why a Battery Makes Winter Solar Even Better

This is where a home battery really earns its keep. In summer, your battery fills up from your panels. In winter, when the sun can't fill it alone, it can charge from the grid overnight on a cheap off-peak tariff.

Here's how a typical winter day might look with a solar and battery system:

1. Overnight: The battery charges from the grid at a low off-peak rate.

2. Morning: You run the house from the battery instead of paying peak prices.

3. Daytime: Your panels top up the battery and power the home while the sun is out.

4. Evening: The battery covers the expensive teatime peak, when energy prices are usually at their highest.

This means you can keep saving money all winter, even on days when your panels produce very little. For many of our customers, the battery is what turns solar from a summer saver into a year-round one. If you drive an electric car, pairing it with a smart charger and an off-peak tariff adds even more winter savings.

5 Tips to Get the Most From Your Solar This Winter

1. Shift heavy loads to the middle of the day. Run the washing machine or dishwasher between roughly 11am and 2pm, when winter sun is at its strongest.

2. Set your battery to charge off-peak. Make sure your battery schedule matches your tariff's cheap hours. If you're not sure, your installer can set this up for you.

3. Review your energy tariff. Tariffs designed for solar and battery homes can make a big difference in winter. It's worth checking yours every few months.

4. Keep an eye on your monitoring app. A sudden drop in output on a clear day could point to a fault or new shading, such as an overgrown tree.

5. Clear the path for light. Trim back branches that have grown over the summer. Low winter sun casts longer shadows, so trees that were never a problem in June can shade your panels in December.

   
   

Is Winter a Good Time to Install Solar?

Many people assume they should wait until spring. In reality, winter can be one of the smartest times to install.

• You're ready for spring. Install now and your system is up and running before the long, productive days arrive, so you don't miss a single month of peak generation.

• A battery starts saving straight away. Even before the sunny months, a battery can cut your winter bills by charging on cheap overnight rates.

• Shorter waiting times. Installers are often less booked up in the winter months than in spring and summer, so you can usually get a survey and installation date sooner.

Installation itself carries on through winter in all but the worst weather. Our team simply plans around the forecast.

The Bottom Line

Solar panels absolutely work in winter. They produce less than in summer because there's less daylight, but they keep generating on cold, cloudy days, and a well-designed system is sized to deliver savings across the whole year. Add a battery, and you can keep cutting your bills right through the darkest months.

If you're wondering what solar and battery storage could do for your home, Solarsmith Surrey can help. We'll look at your roof, your energy use and your budget, then design a system with honest, year-round figures, winter included.

Get in touch with Solarsmith Surrey today for a free, no-obligation design and quote, and be ready to make the most of the sun when spring arrives.