A well designed solar system should give you reliable, consistent performance year after year. So when the numbers don’t look right or your system suddenly seems to dip, it can be frustrating. At Sheerwater Solar, we spend a lot of time diagnosing underperforming systems across Surrey, and the good news is this: most issues have clear, fixable causes.
If your solar isn’t delivering what you expected, here are some of the most common reasons why.
Trees grow, new buildings go up and even small changes in your surroundings can affect how much sunlight reaches your panels. A small patch of shade on one panel can impact the whole array if the system wasn’t designed to handle it. In many cases, optimisers or a redesign of the string layout can make a big difference.
Your inverter is the heart of the system. If it’s ageing, oversized, undersized or starting to fail, your entire output will drop. Warning lights, irregular production or repeated shutdowns are strong indicators that the inverter needs attention or replacement.
Dirt, dust, pollen and bird droppings reduce light absorption and directly cut into your production. Panels don’t need constant cleaning, but they do benefit from occasional maintenance, especially if they’re located near trees or busy roads. A professional clean can restore output much more than people expect – our sister brand Sheerwater Clean can help you with this and keep your panels operating at their best.
If you have a battery or optimisers, a single fault can drag down part of the system or cause mismatched performance. Modern batteries and optimisers have excellent diagnostics, but older models sometimes need a manual check to find the problem.
Many homeowners change how they use energy after installing solar. You might now have an EV, new appliances or a battery. If your original system was designed around old usage patterns, it may no longer be the right size. A reassessment can help make sure your setup matches your lifestyle.
Underperforming solar doesn’t always mean something is seriously wrong. With the right checks, most issues can be spotted early and resolved quickly. At Sheerwater Solar, we take a detailed, practical approach to diagnostics, looking at everything from shading and hardware to data logs and system design.
If you feel your system isn’t performing as it should, we’re always here to help you protect your investment, improve efficiency, and keep your home running sustainably for years to come.
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Reaching out to Sheerwater Solar is straightforward and hassle-free. Whether you’re interested in solar panels for your home or business in Woking, we’re here to guide you every step of the way. You can contact us directly by calling 01932 627 555 or by sending an email to info@sheerwatersolar.co.uk.
Alternatively, fill in our online form for a swift response.
What happens next?
In most cases, we’ll need to conduct an on-site survey at your property to assess the feasibility and provide you with a tailored quote. This visit allows us to understand your specific needs and explore the potential for renewable energy solutions. Following the survey, we’ll discuss the best options for integrating solar energy into your property, including detailed costs and the installation process.
We’re excited to assist you on your journey to renewable energy and look forward to hearing from you.