Does opening the garage door help to keep your house cool?

A partially open garage door might seem like a smart move to keep air flowing, but does it really work?

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When dealing with extreme heat, we are open to trying just about anything to help keep our homes cool. Given that our garages are often poorly insulated, they heat up like ovens when temperatures rise – and some of this heat makes its way into adjoining areas of the home.

Some claim that opening the garage door just a crack will keep your garage cool in hot weather, and in turn help keep the temperature down in adjacent rooms, but is this nothing but a heatwave myth?

We turned to heating and insulation specialists to find out.

'Opening the garage door a crack may allow for some airflow, but it's usually not an effective way to cool down the home significantly,' says Josh Mitchell, HVAC specialist from Air Conditioner Lab. Below, we explain the potential pitfalls and what to do instead.

Josh is an HVAC expert and the owner of the Air Conditioner Lab with years of experience tackling the challenge of home cooling. Josh has explored various innovative methods to cool down living spaces during hot weather.

Leaving your garage door partially open will, of course, increase the ventilation – but is unlikely to cool down your home enough to outweigh the potential hazards.

A garage door left open is likely to invite bugs and other pests inside, which could cause damage to items stored in the garage. Ryan Ratkowski from Rustic Decorating shares a personal anecdote: 'During a blistering heatwave, I decided to leave my garage door slightly open, only to discover later that my space had been hijacked by raccoons,' he says.

'Not to mention dust and other environmental elements can easily invade your space through an open garage. The temptation is big during summer, but spending hours trying to get rid of raccoons was not part of my summer to-do list.'

Pet food may attract mice, and other insects, such as spiders and ants, are more likely to enter if the door is open. This could be remedied by adding a garage door screen, at Amazon, but it would need to be carefully sealed.

We would be most likely to open our garage doors while the air is cooler, either early in the morning or at night, which are also the times that pose the biggest security risk in terms of break-ins and theft. If you have any valuable tools, equipment or any other items stored on your garage shelving or in boxes, be cautious of leaving them unattended.

'Some garage door systems do allow for partial opening without being able to be opened from the outside, which can reduce the security risk a bit,' comments Thomas Scharpf, founder of Schartec, a company that manufactures and sells garage doors, door openers and home improvement devices.

Keeping the garage door open a crack could also put a strain on the door if yours hasn't been replaced for many years. Instead of opening the door, take note of ways to cool down a room, and if doing DIY and decorating in the garage, consider investing in an air purifier to keep air quality healthy and comfortable. Wind and rain could also make its way inside, potentially damaging the door and items you are storing.

There's also energy efficiency to consider. If you have air conditioned rooms near to the garage, opening the garage door could allow this cool air to escape, making the interior feel warmer and resulting in you spending more to keep your home cool.

Andrew Johnson, owner of Texas-based Prime Seamless Gutters & Roofing argues that under certain conditions, leaving the garage door slightly open can help to cool the house down, especially early in the morning or in the evening and more crucially when the outdoor temperature is lower than indoors.

'When you open the garage door during such times, you may still have to open a side door/window for proper ventilation or cross breeze,' he explains. 'This method even works in removing the choking smell of paint or stains.

'However, it's important to be mindful of potential pests that may come in through the garage door. As much as you want to be comfortable, you must bear security in mind,' Andrew advises.

If you are spending time in the garage or front yard early in the morning or late at night, you may be able to keep the garage door slightly open for short periods, but it comes with risks.

HVAC expert Josh Mitchell says that in many cases, it allows unwanted heat, dust, and even insects inside, and instead recommends investing in proper insulation and ventilation for the garage. 'A combination of fans, vents, and perhaps a separate air conditioning unit for the garage might be more effective. Consider the installation of energy-efficient insulation, which is a significant game-changer when it comes to heat transfer reduction,' says Josh.

Otherwise you could opt for blinds or curtains on sun-facing windows to combat the heat, and if you use the garage for workouts or chores, a ceiling fan might just be the answer. It's a safer choice, enhances air circulation, and transforms the garage into a much more pleasant space.

If you live in a humid area, reduce the stickiness with one of the best dehumidifiers.

Decor Ideas. Project Inspiration. Expert Advice. Delivered to your inbox.

Millie Hurst is Section Editor at Homes & Gardens, overseeing the Solved section, which provides readers with practical advice for their homes. She has been in the world of digital journalism for six years, having previously worked as Senior SEO Editor at News UK both in London and New York. She joined the Future team two years ago, working across a range of homes brands. Millie formerly worked as Senior Content Editor at Ideal Home, taking care of evergreen articles that help and inspire people to make the most of their homes and outdoor spaces. Millie has a degree in French and Italian and lives in North London.

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