One of the most common questions we hear from homeowners is: "How many solar panels do I actually need?" The answer depends on several key factors, and getting it right means the difference between a system that barely dents your bills and one that transforms your energy costs entirely.
Understanding Your Energy Usage
The average UK household uses between 2,900 and 3,900 kWh of electricity per year. However, this varies enormously. A two-person flat might use just 1,800 kWh, while a four-bedroom house with an electric vehicle could consume over 5,000 kWh annually.
Start by checking your electricity bills from the past 12 months. Your supplier will show your annual consumption in kWh, and this is the baseline figure you need.
Panel Output and UK Sunlight
Modern solar panels typically output between 380W and 420W each. At Solar Maintenance Solutions, we install 415W panels as standard, which means each panel generates approximately 375 kWh per year in the North of England, and up to 420 kWh per year in Southern regions.
The Quick Calculation
Here is a simple formula: divide your annual electricity usage by 375 (for Northern England) or 400 (for Southern England). This gives you the approximate number of panels needed to offset 100% of your electricity.
- Small home (2,000 kWh/yr): 5-6 panels (Bronze package)
- Average home (3,500 kWh/yr): 9-10 panels (Silver package)
- Large home (5,000+ kWh/yr): 13-16 panels (Gold package)
Roof Considerations
A south-facing roof at 30-35 degrees pitch provides optimal output. East or west-facing roofs lose roughly 15-20% efficiency, meaning you may need an extra panel or two to compensate. Our MCS-certified engineers assess every roof during the free site survey and design a layout that maximises your generation.
Battery Storage Changes the Equation
Without a battery, you typically self-consume around 50% of what your panels generate. With a Tesla Powerwall or EcoFlow PowerOcean, that figure jumps to 80% or higher. This means a smaller system with battery storage can save you more than a larger system without one.
Our Solar Savings Calculator can model this for your specific situation. We recommend every homeowner explores both options before deciding.
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