As Britain braces for another summer of extreme heat, sustainability experts are urging households to use a simple “Caveman Method” to keep their homes cool without turning to expensive, energy-hungry air conditioning.
Experts at Green Doors, the award-winning Luton-based sustainable door and window company, say many people make their homes hotter during heatwaves by opening windows and doors at the wrong time of day.
Instead, founder and CEO Joseph Holman says homeowners should treat their properties like caves during the hottest hours by shutting windows, doors, curtains and blinds to keep hot air and direct sunlight out.
The advice comes after unusually warm weather hit much of the UK during May and has been timed to mark World Environment Day 2026.
While air conditioning is still uncommon in British homes, demand for cooling products is expected to rise as heatwaves become more frequent. Green Doors says households can reduce costs and cut energy use by focusing on passive cooling methods first.
Joseph Holman, CEO of Green Doors, said: “The instinct when temperatures rise is often to throw open every window in the house, but during the hottest hours that can actually make your home warmer. The Caveman Method works by preventing heat from getting inside in the first place.
“World Environment Day is a reminder that some of the most effective environmental solutions are also the simplest. Keeping your home cool without consuming additional electricity reduces both carbon emissions and energy bills, while helping households stay comfortable during increasingly frequent heatwaves.
“The best cooling system is often prevention. If you can stop heat entering your home, you reduce the need for fans, portable air conditioning units and other energy hungry appliances.”
Holman was inspired by traditional cave dwellings in Cappadocia, Turkey, where homes remain cool even during periods of intense outdoor heat.
He says the same principle can help British households prepare for hot weather: block heat before it enters the home, then ventilate only when outside temperatures fall.
Five Sustainable Ways to Keep Your Home Cooler This Summer. Alongside the Caveman Method, Green Doors recommends several environmentally friendly measures that can help households stay comfortable during future heatwaves:
1. Close blinds and curtains before rooms heat up. Blocking direct sunlight can significantly reduce solar heat gain, particularly on south and west-facing windows.
2. Open windows strategically. Keep windows closed during the hottest part of the day and open them during cooler early morning and evening periods to encourage natural ventilation.
3. Reduce unnecessary indoor heat sources. Switch off lights and appliances where possible, as they generate additional heat inside the home.
4. Use external shading where possible. Awnings, canopies, shutters, trees and planting can all help block sunlight before it reaches windows.
5. Invest in long term, passive cooling improvements. Modern glazing, integral blinds, reflective glass and other heat management solutions can help homes remain cooler naturally, without increasing energy consumption.
As a company dedicated to extending the life of doors and windows through reuse and upcycling, Green Doors, which last year won a King’s Award for Enterprise for Sustainable Development, advocates for sustainability being built into every aspect of home improvement.
“At Green Doors, we’re passionate about reducing waste and helping people make more sustainable choices,” added Holman.
“Whether it’s giving a door a second life instead of sending it to landfill, or helping homeowners reduce their energy use during a heatwave, the principle is the same: making smarter use of the resources we already have.”
Green Doors has saved thousands of doors and windows from landfill and continues its mission to promote practical, affordable sustainability across the home improvement sector.
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