The Simple Answer
On average, a typical domestic solar panel in the UK (with a rating of around 400W) generates between 300 and 450 KWH per year. Multiply that by the number of panels on your roof, and you’ll have a good estimate of your system’s annual output.
The Detailed Answer
The actual amount depends on several key factors:
- Panel Wattage: Today’s residential panels range from 350W to 450W. The higher the wattage, the more electricity generated.
- Sunlight Exposure: South-facing roofs with minimal shade will always perform best. However, modern systems—like those we install with SolarEdge optimisers—can handle partial shading and varied roof angles efficiently.
- Location: Solar panel output varies across the UK. Southern England receives more sunlight than northern Scotland, but even in less sunny areas, solar remains a smart investment.
- System Design: The total number of panels, their arrangement, and the inverter’s efficiency all play a role.
Example Calculation
Let’s say you install a 400W panel on a south-facing roof in Warwickshire. On average, that panel will generate:
- Daily: 1.1 KWH (in summer), 0.3 KWH (in winter)
- Annually: 350–400 KWH
A typical 10-panel (4kW) system might generate 3,600–4,000 KWH per year—enough to cover around 60–80% of an average UK household’s electricity needs.
How Much Electricity Does a 100W Solar Panel Produce?
A 100W solar panel is much smaller and is often used for sheds, caravans, or off-grid applications. In UK conditions, you can expect:
- Daily: 0.25–0.3 KWH (summer peak)
- Annually: 90–110 KWH
While not suitable for powering a whole home, these panels are perfect for charging small devices or providing a backup supply.
How Do Weather and Seasons Affect Output?
Solar panels work all year round—even in cloudy Britain. While peak summer months deliver the highest generation, panels still produce electricity on overcast days. Modern panels, like those from SunPower and GivEnergy, are engineered for high efficiency in low-light conditions.
- Summer: Up to 70% of your annual output is generated between April and September.
- Winter: Output drops, but your system continues to produce valuable electricity.
How Much Electricity Will My System Produce?
Every home is unique. At Stratford Energy Solutions, we design bespoke systems tailored to your roof, lifestyle, and energy goals. Here’s what you can expect:
- 4kW System (10 x 400W panels): 3,600–4,000 KWH per year
- 6kW System (15 x 400W panels): 5,400–6,000 KWH per year
- 10kW System (25 x 400W panels): 9,000–10,000 KWH per year
These figures assume optimal conditions. Our advanced site surveys and shading analysis ensure you get the most accurate forecast for your property.
Can Solar Panels Really Cover All My Electricity Needs?
For many UK homes, a well-designed solar system can meet the majority of annual electricity demand—especially when combined with battery storage. Our customers regularly achieve up to 80% bill reductions, with some even exporting surplus energy back to the grid for additional income.
How Battery Storage Maximises Your Solar Output
Pairing your panels with a battery, such as the Tesla Powerwall or GivEnergy, allows you to store excess daytime energy for use in the evening or during grid outages. This means:
- Greater self-sufficiency
- Reduced reliance on the grid
- Enhanced savings
Stratford Energy Solutions is a Tesla Powerwall Premium Installer, ensuring seamless integration and premium aftercare.
Real Results: Stratford Energy Solutions in Action
Our installations across Warwick, Kenilworth, Worcester, and Solihull showcase what’s possible:
- Precision Micro (Commercial): 260 panels, 23.78 tonnes CO2 saved annually, £2,460 monthly savings
- Bening Family (Residential): 16 Maxeon panels + Tesla Powerwall, designed for partial shade, delivering significant annual energy savings
These are more than numbers—they’re stories of empowered customers, lower bills, and a lighter environmental footprint.
Common Questions About Solar Panel Output
How much electricity does a solar panel produce daily?
A 400W panel in the UK produces about 1.1 KWH per day in peak summer, dropping to 0.3 KWH in winter.
How much electricity does a solar panel produce per month?
Multiply the daily average by 30. For a 4kW system, expect 300–350 KWH per month in summer.
How much does a solar panel produce over its lifetime?
Panels are warranted for 25+ years. Expect 90%+ output after 10 years, 80%+ after 25 years.
What factors affect solar panel output?
Panel quality, orientation, shading, weather, and system design all play a part.
Maximising Your Return: Tips from the Experts
- Choose premium panels for higher efficiency and longer lifespan.
- Keep panels clean and free from debris for optimal performance.
- Monitor your system with smart apps to track generation and usage.
- Invest in battery storage to maximise self-consumption.
The Environmental Impact: More Than Just Savings
Every KWH generated by your solar panels is a KWH not drawn from fossil fuels. In just one month, Stratford Energy Solutions’ installations produced 386 megawatt-hours—enough to boil over 5,000 kettles and prevent dozens of tonnes of CO2 emissions.
Conclusion: Your Next Step Towards Energy Independence
Understanding how many KWH a solar panel generates is the first step towards transforming your home’s energy future. With the right system, expertly installed and supported, you’ll enjoy lower bills, greater control, and a positive impact on the planet.
Ready to discover exactly how much you could save?
Contact Stratford Energy Solutions for your free, bespoke solar assessment today.