What Homeowners in the South East Should Expect
If you live in the South East and are considering solar panels, it is completely natural to wonder “Will my solar panels be worth it in winter?” Shorter days, cloudy skies and cold weather – sounds like a bad recipe for solar, right?
The reality is more positive than most people think. Modern solar PV systems continue to generate useful electricity throughout winter, and the cold weather can actually improve panel performance.
In this guide we’ll explain how solar works, efficiency, generation levels and common myths in winter.
Winter Solar Irradiance in the UK
Solar irradiance is the amount of solar energy reaching a given area. It varies by season, weather and location. In the UK:
- Solar irradiance is highest from April to September and lowest from November to January.
- A typical UK roof will generate far more electricity in summer than in winter, this is completely normal.
- However, even in the darker months, daylight (not just direct sunshine) still drives solar generation.
South East England: A Sunnier Part of the UK
The South East is one of the best performing regions in the UK when it comes to solar power. It generally receives above average annual solar irradiation compared with northern and western regions. Coastal and southern areas such as Sussex, Kent and Essex often see more bright winter days than inland northern locations.
While exact output depends on your roof orientation, shading and system size. Many South East homeowners see roughly 15-25% of their annual solar production from the winter months (November to February). The key message: output drops in winter but it does not stop, and in the South East, conditions are comparatively favourable.
Cold Weather Can Improve Solar Panel Efficiency
One of the biggest surprises for homeowners is that solar panels dislike heat more than cold. Solar panels are tested at a standard temperature of 25°C. As panel temperature rises above this, output gradually decreases due to what is called the temperature coefficient. On very hot days, panels can reach 40-60°C on the roof, causing a small efficiency drop. In cold, clear winter weather, panels often operate closer to their ideal temperature range, which can make each unit of sunlight more productive.
So while there is less total sunlight in winter, the panels themselves are working in a more favourable temperature range. When a bright, crisp winter day arrives, your system can perform very efficiently.
What Kind of Winter Output Should You Expect?
Exact figures will depend on your property, but here is a simplified view for a typical domestic system in the South East.
Consider a 4kW solar PV system on a south facing roof with minimal shading. Over a full year, such a system will often generate in the region of 3,400-4,000 kWh of electricity. In December and January, monthly generation might be around 10-20% of peak summer months.
A sunny June might generate 380-420 kWh, while a typical December may only generate 70-120 kWh of electricity. However, even at these lower levels, the winter production of your solar panels still offsets electricity you would otherwise be buying from the grid, helping to power lighting, appliances and standby loads. Your winter solar production can also feed into a solar battery for use when you need it most.
The important thing to see is solar is a 12 month system, strong production in the spring and summer, moderate in autumn and lower but still meaningful in winter.
Cloud, Rain and Overcast Skies: Do Panels Still Work?
Yes, solar panels work on daylight, not direct sunshine. In winter, overcast days reduce output but rarely drop to zero. Diffuse light (when the sky is cloudy) still contains solar energy, and the South East experiences many seasons in a day, short sunny spells between cloudy periods, which can deliver useful generation spikes.
Modern inverters track the optimal operating point of your array in real time, ensuring your system captures as much energy as possible from available light, whether direct or diffuse.
Snow, Frost and Ice: Will They Stop My Solar Panels?
In much of the South East, heavy settled snow on roofs is relatively uncommon. When it does occur:
- A thin layer of frost or light snow may temporarily reduce output
- Glass fronted panels are smooth, so snow typically slides off once the sun comes out or temperatures rise slightly
- The small amount of heat generated during operation can help clear panels more quickly
In the rare event of heavy snowfall:
- It is not recommended to climb onto the roof or attempt to clear the panels yourself due to safety
- In most cases, any loss of generation is short lived and has minimal effect on annual output
Common Misconceptions About Solar Panels in Winter
Misconception 1: “Solar panels do not work at all in winter”
They absolutely do, output is lower, but generation continues throughout the daylight hours. Many homes still see noticeable savings on winter electricity bills.
Misconception 2: “UK winters are too dark for solar to be worthwhile”
While winter is darker, solar economics are based on annual production, not just winter. The strong spring and summer performance in the South East compensates for low winter output, which is why payback periods for well designed systems remain lower in the South East.
Misconception 3: “Solar panels only work in hot countries”
Solar relies on light, not heat. Many high performing solar markets have climates comparable to or cooler than the UK. The South East’s relatively good solar resource makes it especially suitable.
Misconception 4: “Batteries are pointless in winter”
A battery may not fully charge every day in winter, but it can still capture daytime generation to use in the evening peak. Solar batteries also help you benefit from off peak tariffs, charging your battery over night on lower priced grid electricity then using it during the evenings when grid electricity is at its peak price.
How to Maximise Winter Performance from Your Solar Panels
To get the best possible winter performance in the South East:
1. Good system design
- Optimised panel layout for your roof orientation and pitch
- High quality panels and inverter matched to your usage
2. Minimise shading
- Avoid chimneys, trees and adjacent buildings shading key parts of your solar array
- Consider SolarEdge power optimisers if unavoidable shading affects parts of your roof or you have panels on different orientations
3. Regular monitoring
- Check your online portal or app to see how your system is performing each season
- Spot any sudden drops that might indicate a fault or issue early
4. Combine with a battery (optional)
- Store excess energy in brighter winter periods
- Improve self-consumption across the whole year
5. Use electricity smartly
- Shift flexible usage (dishwashers, washing machines, EV charging) into daylight hours while your solar panels are generating free electricity where possible
- Even in winter, this helps you make more direct use of your solar output
Is Solar Still Worth It If Winter Output is Lower?
For most South East households, the answer is an outstanding yes, provided the system is properly designed and installed for your property and not a standard off the shelf system.
When assessing the value of solar, you should consider:
- Total annual generation, not just winter output
- Rising electricity prices and potential future price volatility
- The lifespan of solar panels (minimum of 25 years with performance warranties)
- The added resilience and energy independence a solar PV and battery system can provide
A well designed system will deliver the majority of its production from March to October, with winter acting as the quieter season but still contributing meaningful savings.
Considering Solar Panels in the South East? Speak to SolarTherm UK
If you are based in the South East and are curious about how solar panels would perform on your specific roof, the best next step is a tailored assessment.
SolarTherm UK can
- Analyse your roof orientation, shading and location
- Provide realistic monthly generation estimates and savings, independently verified by EPVS (Energy Performance Validation Scheme) for accuracy
- Design a system with or without battery storage, aligned to your budget, energy use and future energy needs
- Handle installation, commissioning and aftercare
Contact SolarTherm UK today for a free, no obligation quote and design, tailored to your property, usage and future energy needs. No hard sell, just honest, expert advice.
Your home. Your energy. Your future.
