Surprise! Insulation Cools Too
When most people think of loft insulation, they think of staying warm in winter. But did you know that a properly insulated loft can actually help keep your home cooler in the summer months too? Yep, not very intuitive is it?! Fact: your loft space could be acting like a giant oven with heat radiating down into the rooms below. But using the right insulation acts like a barrier—stopping that heat from making your home uncomfortable during hot spells.
Let’s break down how it works—and what you can do to make the most of your insulation this summer.
The Science: Why Heat Rises… and Why It Also Falls
Your roof takes the brunt of the sun’s rays all day long. As it heats up, the loft space beneath it can reach sweltering temperatures—often exceeding 40–50°C in the summer. And the bad news is: without proper insulation, that heat slowly transfers downward through the ceiling and into your living spaces. 🥵
But here’s the good news: with proper loft insulation in place (plus an insulated loft hatch), that heat is blocked and slowed—just like in winter, only in reverse! According to our Loft Insulation Guide, materials like mineral wool trap heat by reducing thermal conductivity, whether that’s keeping warmth in or out.
👉 It’s all about thermal resistance—and good insulation works both ways.
Practical Proof That Insulation Works (Not Just Theory)
Want to see the real-world impact of proper loft insulation in summer? One homeowner’s experiment, detailed in a post from Get Energy Savvy, provides striking visual evidence. After removing a small patch of insulation roughly the size of a dinner plate, they used a thermal imaging camera on a hot summer day. The result: a 4 °C hotter “hot spot” on the ceiling directly beneath the uninsulated area, compared to the properly insulated sections .
“The hot spot on the ceiling is at least 4 °C warmer than the properly insulated ceiling around it.”
This experiment confirms the point we make here: even small gaps or thin insulation can cause noticeable heat to leak into your rooms. If your insulation isn’t tidy, complete, or up to the recommended depth of 270 mm, you could be letting unwanted heat in—just like that kitchen-plate-sized patch in the thermal image.
🔗 Read the full experiment and see the imaging results for yourself at Get Energy Savvy’s article: “This is how helpful loft insulation is in summer at keeping you cool”.
What Happens Without Insulation
Without insulation:
- Loft temperatures rise fast in direct sunlight
- Heat builds up and is conducted through ceiling plasterboards
- Upstairs rooms feel stuffy, hot, and hard to cool—even with fans
With insulation:
- The thermal barrier blocks heat from moving into your home
- Temperatures downstairs remain far more manageable
- You reduce the need for fans, A/C, or opening windows to hot air
DIY Checks You Can Do This Weekend
- Inspect your loft hatch: Is it uninsulated or draughty? Use a thick insulated cover or attach foam insulation board
- Measure your insulation depth: Anything less than 270mm may need topping up
- Check for gaps or compression: Squashed insulation won’t work properly
- Improve ventilation: Roof ventilation helps prevent heat and moisture build-up
Pro Tip
If your insulation is outdated, damp, or incorrectly installed, it won’t protect you in summer or winter. The Loft Boys offer a full insulation inspection (during your free survey) and fitting service using the latest materials for maximum year-round benefit.
Loft Insulation Isn’t Just About Lower Energy Bills
We usually talk about insulation in terms of saving money on winter heating—but in reality, better insulation means:
- More comfortable bedrooms during hot nights
- Lower cooling costs if you use fans or air conditioning
- Reduced wear and tear on roof timbers due to extreme heat cycles
Conclusion: Stay Cool with a Smarter Loft
If you’re sweltering upstairs during summer, your loft may be to blame. Investing in good insulation isn’t just about staying warm—it’s about staying comfortable year-round. And don’t forget about the loft hatch—if that’s also not insulated it could be another way to for heat coming in or out.
Want to know how your loft’s doing?
Get in touch with The Loft Boys today to book your free loft survey.
Request a quote todayWas this post useful? Here are some other’s you might like...
Beware of the Latest Loft Insulation Scam: Protecting Yourself and Your Loved Ones
