Did you know creating a free 'DIY Cool Room' saves you money, keeps you comfortable, and makes a 'big difference' in summer?

Fall may be on the horizon, but temperatures across the U.S. aren't set to drop anytime soon. If you've been struggling to cope, we've got the perfect solution – a DIY Cool Room. Better yet, it doesn't have to cost a single cent.

With one of the main caveats to using AC being the cost, this clever DIY trick focuses on cooling just one space, rather than your entire home. In turn, this helps you to save money and provides welcome relief to the sweltering heat at the same time.

Here, HVAC pros explain exactly how to make one, and why a DIY Cool Room works to keep you cool.

What is a DIY Cool Room?

As Josh Mitchell, HVAC technician and founder of Air Conditioner Lab, assures, 'When your whole house feels like an oven and running central air all day isn’t practical, creating a DIY Cool Room can make a big difference.'

In fact, he's tried this method himself to keep his home cool in a power outage, and even helped clients set it up when they're trying to save money at home and cut energy bills.

'It’s exactly what it sounds like,' he continues. 'Instead of trying to cool your entire house, you focus on one room.

'You turn that space into your main comfort zone, especially during the hottest part of the day. You bring your fans, AC unit, or other cooling gear into the room, close the doors, and stay there until the outside temperature cools down,'

This aligns as a modern-day version of the 'caveman cooling method,' and is one of the most efficient ways to run your AC during a heatwave.

Why does a 'DIY Cool Room' work?

A DIY Cool Room works, explains Josh, because lowering the temperature in one room is always going to be faster and easier than attempting the same for your whole home.

This way, you're cooling down a room at speed and with focus, rather than fighting heat in every corner.

'A standard 8,000 BTU AC unit takes about 20 minutes to cool a 250 square foot room by five to seven degrees,' he advises. 'In contrast, trying to cool the whole house might take hours and cost way more in electricity.

'By blocking off airflow and focusing your cooling power in one space, you put less strain on your equipment and stay comfortable without running up the bill.'

Therefore, this effective and unusual method for staying cool at home helps to escape any reason your home feels hot, without actually having to cool the entire space.

How to set up a 'DIY Cool Room'

To set up your DIY cool room, it's best to pick a space that's naturally cooler if possible, recommends Josh.

'North-facing rooms or those with fewer windows tend to stay cooler during the day,' he advises.

For this reason, Glenn Wiseman from Top Hat Home Comfort Services, says a basement is ideal.

Then, close all the doors and block out sunlight, either with blackout curtains, such as the Mainstays Iris Linen Look 100% Blackout Curtain Panel Pair available at Walmart, a thick blanket, or even cardboard.

If you're wondering whether blackout curtains keep heat out, 'This alone can reduce indoor temperature by two to three degrees,' says Josh. It's also been Head of Solved Punteha van Terheyden's secret heatwave solution for a decade.

Next, bring in a portable air conditioner or window unit, if you have one. 'The bestselling Midea AC Window Air Conditioner available at Amazon is quiet and energy-efficient,' says Josh, 'making it ideal for rooms around 300 square feet.

'If you’re using a portable AC, make sure the exhaust hose is properly sealed in the window. I also like the BLACK+DECKER Portable Air Conditioner available at Amazon, which works for small bedrooms or offices.'

Finally, all that's left to do is bring in your best fan or two to help move the cooled air around the room.

'Position one box fan in the window facing out to push hot air out of the room, and one inside blowing cool air toward you,' suggests Josh. 'The Vornado 630 Circulator Fan available at Amazon is a compact yet powerful circulator that performs well in tight spaces, helping distribute air evenly without taking up much room.'

To boost the effect of your fan, Glenn adds that you can actually engineer your airflow by rotating frozen water bottles or ice packs in front of your fan, which is a clever way to make a DIY air conditioner.

'This works because the cold water or ice with a fan allows the air flow to pull heat out of the air,' he explains. 'But, even without ice and with warm air, fans simulate a wind chill,' so this extra step certainly isn't necessary if you don't happen to have any ice on hand.

'It’s not high-tech, but it can drop the air temperature in your immediate area by a few degrees,' Josh adds.

'DIY Cool Room' essentials

Meet our experts

Josh Mitchell

Air Conditioner Lab was founded by HVAC and tech enthusiast Josh in 2014, as a way for him to document his findings on home air conditioners and cooling methods, including affordable DIY methods like making a 'Cool Room' to save money on energy bills.

Another clever and affordable way to cool down your space is with the sheet cooling hack, which 'turns an underperforming setup into something surprisingly effective' according to HVAC experts. You can also set up a cross-draft to quickly reduce the heat without an AC unit.