Maximising Your Solar PV System in the UK During Winter

Winter in the UK brings shorter days, lower sun angles, and often cloudier weather. For solar PV system owners, this can feel like a time when your panels aren’t pulling their weight. However, with some planning and smart energy habits, you can still get the most out of your solar investment—even in the darkest months.

1. Understand Winter Solar Production

• Shorter Days, Lower Sun Angle: In December, the UK can see as little as 7–8 hours of daylight. Solar panels receive sunlight at a lower angle, which reduces efficiency slightly compared to summer.

• Lower Temperatures Are Actually Helpful: Cold weather improves panel efficiency. Unlike heat, which can reduce output, crisp winter days can generate more electricity per hour of sunlight.

• Cloud Cover: Solar systems still generate electricity on cloudy days, though at 10–25% of peak output depending on cloud density.

  
  

Tip: Checking your system’s performance via your inverter app or monitoring platform will help you see what’s realistic during winter.

2. Optimise Panel Orientation and Cleaning

• Angle Matters: For fixed panels, tilt between 30–40° in the UK generally captures the best winter sunlight. Some homeowners with adjustable mounts tilt panels steeper in winter to catch lower sun angles.

• Keep Panels Clean: Rain usually does a good job of cleaning panels, but winter debris—fallen leaves, frost, or snow—can reduce output. Gently removing obstructions improves performance.

• Shading: Shorter daylight means that even small shadows (from chimneys, trees, or neighbouring buildings) have a bigger impact. Trim any overhanging branches or foliage.

  
  

3. Shift Energy Use to Daytime

• Time Your Appliances: Running washing machines, dishwashers, or charging electric vehicles when the sun is shining maximises self-consumption of solar electricity.

• Smart Plugs and Timers: These can automatically run appliances during peak sunlight hours.

• Battery Storage: If your system includes a battery, store excess energy during the day and use it in the evening to reduce reliance on expensive grid electricity.

  
  

4. Monitor Performance Closely

• Track Output: Use your solar monitoring software or inverter display to see how much energy your panels are producing.

• Compare Month-to-Month: Seasonal dips are normal, but sudden drops could indicate a fault, shading, or dirt build-up.

• Act Early: Promptly addressing any issues keeps your system efficient year-round.

  
  

5. Maximise Feed-In Tariffs and Export

• UK Smart Export Guarantee (SEG): Even if you’re generating less electricity, exporting surplus solar to the grid can still earn money.

• Combine with Energy Efficiency Measures: Reducing household consumption during winter (e.g., LED lighting, draught-proofing) ensures more of your generated electricity goes to valuable use.

  
  

6. Plan for Snow and Frost

• Snow: Snow usually slides off panels due to their smooth surface and tilt, but persistent snow can block sunlight. A long-handled soft brush or a roof rake designed for solar panels can clear it safely.

• Frost: Panels are fine under frost; it generally melts quickly once the sun rises.

  
  

7. Consider System Upgrades

• Add a Battery: Storing daytime solar for evening or overnight use improves winter self-consumption.

• Smart Home Integration: Using apps to schedule heating or EV charging based on solar production helps maximise savings.

• Panel Cleaning & Maintenance: Professional checks before and after winter ensure optimal performance.

  
  

Key Takeaways

1. Winter solar output is naturally lower, but cold weather helps efficiency.

2. Align panels, reduce shading, and keep them clean for maximum sunlight capture.

3. Shift energy-intensive activities to daylight hours and consider battery storage.

4. Track performance and address issues promptly to maintain output.

5. Export surplus energy through the SEG for additional financial benefit.

   
   

With these strategies, UK homeowners can keep their solar PV system productive, save on energy bills, and continue to reduce carbon emissions—even in the shortest, greyest days of winter.