When we think about insulation, most of us picture cold draughts and heating bills. But with summer temperatures rising – and hot spells becoming more common in the UK – it’s worth remembering that insulation can also help keep your home cooler when it’s warm outside.

These days, more and more people are asking us about overheating in their homes. From stifling loft conversions to bedrooms that feel like ovens, high summer temperatures can make it hard to stay comfortable – or even safe.

It’s not just about comfort. Once indoor temperatures creep above 24°C, the risk of heat-related health issues rises – particularly for older people, young children, and anyone with a heart or respiratory condition. And it’s not just in Southern Europe: UK homes are among the least prepared in Europe for extreme heat.

What about humidity?

Hot weather and high humidity are a bad mix indoors. When air is damp, it becomes harder for sweat to evaporate, making it much harder for our bodies to cool down. That’s why managing moisture is a key part of keeping homes healthy in the summer, too. Breathable insulation materials can help regulate indoor humidity, avoiding the trapped, stuffy feeling you often get in poorly ventilated homes.

Where can you insulate?

It’s not just about the loft. Insulating walls, roofs, and floors – especially in converted lofts or sun-facing rooms – can all make a big difference. And when done with the right materials, you’ll feel the benefit year-round.

How insulation helps in hot weather

Insulation works both ways. In winter, it helps keep heat inside. In summer, it slows the heat coming in – helping your home stay cooler for longer.

Natural materials like woodfibre do this particularly well. They have a high thermal mass, which means they absorb heat slowly and release it gradually. In practice, that can delay heat build-up inside your home by 8 to 12 hours – keeping things cooler during the day, and more comfortable overnight.

It’s one of the reasons we recommend natural, breathable materials. Independent tests show they outperform many plastic-based insulations in extreme heat. In fact, natural options typically have five to ten times the thermal storage capacity of synthetic ones – meaning they absorb and release heat much more slowly. That helps delay overheating and keeps indoor temperatures more stable, even during a heatwave.

Avoiding the rush to air-con

Sales of air conditioning units have surged in recent years – and with it, energy use and emissions. But natural insulation offers a lower-carbon, low-maintenance alternative to mechanical cooling. Get it right, and you may not need to plug anything in at all.

Real homes, real benefits

Ironically, most people come to us to stay warm in winter – but the bonus is often a cooler home in summer. One example we often showcase is a 1930s end-of-terrace house that went as far as wrapping the whole home in woodfibre and external wall insulation. The result? Year-round comfort, and a clear sign that good insulation works both ways. It’s well worth exploring our other success stories to see what’s possible.

Too hot to sleep? Let’s talk.

If your home’s too hot in summer and too cold in winter, you’re not alone – but there is a better way. We can’t fix it overnight, but we can help you plan ahead. Smarter upgrades can make your home cooler in summer, warmer in winter – and more comfortable all year round.

Want to find out what’s possible for your home? Give our friendly team a call on 0330 223 2742 (Monday to Friday) or message us – we’re always happy to schedule a chat.

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Want to dig deeper?

If you’d like to understand more about how natural insulation performs in hot weather, these resources are a great place to start – or just have a chat with our knowledgeable team. Lina, in particular, has a real passion for insulation and is always happy to talk it through.

• What to consider when choosing natural vs synthetic insulation – from Ecological Building Systems
• Comparison of insulation materials – developed with GreenSpec, a trusted authority on sustainable building
• Types of insulation explained – from the Centre for Alternative Technology (CAT)