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Tom’s Guide
Tom’s Guide
Technology
Grace Dean

I tried a 'night flush' on my home to beat the heatwave — and it works like a charm for keeping things cool

A thermometer outdoors in a heatwave.

Some couples argue about what's for dinner or who needs to take the bin out next. In my house, we've recently argued over how to keep cool in a heatwave. Granted, when it gets really hot, everyone's tempers are a little... shorter, but I firmly stood by my point that during the scorching weather, we should be keep the windows closed.

In fact, what I really wanted to convince him to do was 'house flushing' and after the most recent heatwave, I've finally converted him. Performing a 'house flush' sounds unusual, but it's actually pretty simple. It's a technique that takes closing the windows to the next level and it's quickly become my favorite heatwave hack. Paired up with the 'caveman method', I'm managing to keep my house a heck of a lot cooler.

How does it work?

@gbisbydiy ♬ Gets Like That (Jamie Jones Remix) - Jamie Jones & Max Dean & Luke Dean

To perform a 'night flush' on your home, you keep your windows closed during the day when it's hotter outside than it is inside. Then, at night, when (or if) it gets colder outside, you can open up the windows and flush out all the heat from inside and invite in the finally cooler air.

As @gbisbydiy explains on TikTok: "The key is understand when to let the outside air in and when to keep it out. Avoid the common mistake of opening windows when the temperature outside is higher than inside. This only services to let more heat into your home. Instead, focus on utilizing cooler periods, particularly overnight, to your advantage."

Like flushing a toilet, grab hold of those window handles and release them to open up your windows and dump out all that hot air that's accumulated inside. Then, you'll hopefully achieve a much cooler and more relaxing evening.

Here's what happened when I tried it

(Image credit: Shutterstock)

Ever since I wrote about the 'caveman method' in 2025, I've sworn by keeping my windows covered during a heatwave, turning my house into a cool oasis (or at least cooler than outside).

But still, sometimes my husband will start going around opening them up and telling me to let some air in and that's when we end up having to argue about it. When I found out about 'night flushing' I felt a little more vindicated and thought I'd give it a try, pitching it to my husband as another one of those hacks that I find that actually turns out to be really useful.

And it's been the perfect happy medium that we needed. My husband was happy to have the windows open at night and I got to keep them shut during the day. During the most recent heatwave, I tried performing a 'night flush' for almost an entire week and it worked out great.

I felt a distinct difference in the indoor temperature to outside during the day and kept the windows shut overnight if it didn't feel like it was any cooler outside than in at night. When it was cooler, I let the breeze blow through my home. Then, once the hot weather broke entirely, I performed an all-day flush on my home, keeping the windows open and performing a full cleanse of all the heat that might have been hiding inside. Bring on the next heatwave!

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