Busting the Heatwave Myth with Solar Essex

When summer temperatures rise, one of the most common questions we hear at Solar Essex is:
“Do solar panels stop working when it gets really hot?”

It’s a fair concern — after all, solar panels sit in direct sunlight all day. But the truth might surprise you. Let’s break down how panels handle the heat, what conditions they work best in, and when you can expect peak performance throughout the year.

Do Solar Panels Still Work in Extreme Heat?

Yes — and very reliably. Solar panels are designed to operate in conditions far hotter than anything the UK will ever see. Most are tested to function up to around 85°C, with operating ranges typically between -40°C and 85°C.

It’s true that efficiency drops slightly once the temperature goes above 25°C, but the impact is minimal. For example:

• At 40°C, your panels will still perform at around 95% efficiency.
• Compare that to a dull, overcast day, when output can fall as low as 33% efficiency.

So, even in a heatwave, panels continue to produce clean electricity at very high levels.

Could Hot Panels Become a Fire Risk?

The idea that overheating solar panels might catch fire gets mentioned now and then — but the evidence doesn’t back it up. A 2018 UK study found that fires involving solar PV were the result of faulty components or poor installation, not high temperatures.

In reality, the main “danger” of heat is simply a small dip in efficiency, not a safety hazard.

What’s the Ideal Operating Temperature?

Panels actually thrive in cooler sunshine. The sweet spot is usually between 1°C and 20°C on a bright, clear day. Above 25°C, efficiency edges down slightly, but not enough to cancel out the benefits of long summer daylight hours.

Which Months Deliver the Most Energy?

For UK homes, May to July is the golden window for solar generation. The combination of long daylight hours and mostly clear skies makes this period the most productive.

That said, panels don’t “switch off” in winter. Even from November to January, a well-positioned south-facing system can generate around 12% of its annual energy output.

Can You Keep Solar Panels Cooler?

On big solar farms, you might see cooling techniques like fans or water sprays to counteract heat. But for homeowners, it’s generally not worth the effort or expense — panels are designed to cope perfectly well with UK summers.

If you do want a quick DIY trick on an especially hot day, spraying the panels with water can help lower their temperature while also washing away dust. Just make sure to avoid electrical components and wiring, as water exposure can affect warranties.

The Takeaway

Heat has only a minor impact on solar output, and UK conditions are nowhere near extreme enough to cause problems. Solar panels are built to handle a wide range of climates, making them an excellent choice for Essex homes and beyond.

Thinking of Going Solar?

At Solar Essex, we provide tailored system designs based on your home, energy use, and future needs. No pushy sales — just clear, expert advice.

📞 Call us today to start your solar journey.