My rented house was like an oven, so I was thrilled when this 5-minute pantry staple was the secret to cooling it down damage-free

I work upstairs in my home office most of the day, and during the summer the heat used to be absolutely relentless – until I tried the clever aluminum window cooling hack that HVAC pros swear by.

It involves taking a few sheets of aluminum and covering windows with them in order to deflect light and warmth. I gave it a go, and now I do it on the days when my home office is particularly sweltering. I also spoke to the pros about why this DIY solution is so effective.

For those searching for ways to keep the house cool during heatwaves and are yet to try this clever technique, this is one worth giving a go.

What is the aluminum foil window cooling hack?

Essentially, putting foil, available at Walmart, on your windows works to cool down rooms because it not only blocks light, but also reflects light and heat away from your home. It's a renter-friendly hack as no permanent changes are needed and it only takes five minutes to put up.

Carr Lanphier, CEO of Improovy, adds, ‘I have found this to be a good technique in a pinch, especially if we’re experiencing extreme heat and the AC isn’t cutting it, or in rooms that get very hot throughout the day due to direct sun coming in through a window.’

While having one of the best fans is a great way to keep heat at bay, it’s always a good idea to combine different cooling techniques for the best results. I was struggling to come up with new solutions to try, until home improvement pros suggested that I try the aluminum foil hack.

Scott Levene, vice president at Levco, adds, ‘It can help reduce indoor temperatures and ease the strain on your AC system, especially in rooms that tend to overheat during the hottest part of the day.’

Scott adds that you don't need to put foil on every window – simply focus on windows that get direct sunlight.

Where can I try hanging aluminum foil during a heatwave?

I used it in my home office, as this is on the second floor in my house and is where I spend most of my 9-5 days. It also has a large window that I can reach easily – even with me being five foot two.

It’s best used on windows inside that are accessible, allowing for quick application, protection from the elements, and easy removal.

However, Carr stresses that the major con of this is looks – let’s just say it isn’t the most glamorous of techniques – so make sure to use it in rooms that guests won’t come across, like offices, storage rooms, and bedrooms.

‘It will also completely block light through that window and make your room or home very dark,’ Carr adds.

You can also use portable blackout curtains, available at Amazon, which stick on your windows with suction cups and are super effective, according to Head of Solved, Punteha van Terheyden, who has been using them for a decade to do exactly this.

How to do the aluminum foil window cooling hack

Wondering how to try this hack yourself? It’s super simple – and Joe Haycock, vice president at Fresh Air Concepts, has explained the steps below:

• Measure the window: Take a look at the window and measure just the glass part, not the whole frame. Use a high-quality tape measure, such as the Komelon power tape from Amazon.
• Cut a piece of aluminum foil: Make sure that this is a little bigger than the glass, so it covers everything you need.
• Gently crumple the foil a bit so it is not perfectly flat: This helps it stay in place and cuts down on reflections.
• Press the foil up against the inside of the glass: Ensure the shiny side is facing out toward the sun.
• Use masking tape around the edges to hold it in place: Tape the foil to the window frame, not the glass, and keep it a little loose so things do not get too hot underneath.

Top tip: Even if you’re doing this trick indoors, make sure to use weather-resistant tape (such as the Amazon Basics adhesive tape) to keep it safe from window condensation and humidity.

What to shop

Combining a number of cooling methods together will help you stay comfortable in the summer, especially if your home does not have AC.

All prices were correct at the time of publication.

Meet our experts

Carr Lanphier

Carr is the CEO of Improovy, which helps people find home renovation solutions in their area. He is a pro at fixing up homes and loves finding innovative ways to make rooms look and feel better.

Scott Levene

Scott is the vice president at Levco, which is an oil and HVAC service company in Trumbull, CT. Scott has been working for the company for over 18 years, and has helped numerous clients find smart cooling solutions.

Joe Haycock

Joe Haycock is the vice president at Fresh Air Concepts, a family-owned and operated HVAC company with nearly 30 years of experience serving residential and commercial customers in and around Baltimore.

Want to try even more clever cooling tricks? The caveman cooling hack, the sheet cooling hack, and the cross draft hack are also worth giving a go.