Cracking The Garage Door Helps With Summer Heat, But There Are Downsides

Summer has officially begun, and seasonal forecasts from NOAA show most of the U.S. will see temperatures above historical averages. It seems like we're going to be seeing a hot and dry one, potentially with weather patterns forming a "super El Niño" as summer fades. Make sure your air conditioning system is up to snuff, because it's going to get pretty warm in the coming months. You should also make sure your garage has an appropriate level of ventilation, especially if you live in the American Southwest. Keeping the garage door open a crack seems to be a popular "hack" for keeping home temperatures lower as the heat index rises.

Many homes have an attached garage and that garage is typically not as well insulated as the rest of the house, which can trap hot, stagnant air. A hot garage can stay warmer than the outside air much longer if there's no ventilation. And with a hot garage, the shared walls between your home and your garage also heat up, using the cool air inside your home as a heat sink. A hot garage can mean a hot home, or at least an air conditioning system that is working overtime. 

Cracking your garage door open on a hot day can certainly help cool off a garage as it helps promote air circulation and helps evacuate some of the hot air. At best, this is a stop-gap solution. A better move is always to properly insulate your garage, and make sure it has appropriate ventilation built in. It may not always be possible to invest in properly insulated walls, windows, doors, and ceilings for your garage, whether for budgetary reasons or because you rent the home you live in, but it's what will keep your garage coolest. If cracking your garage door is the only way to keep your garage cooled off, then it's an approach worth trying, but there are drawbacks. The two main drawbacks? Critters and thieves. 

Unwanted guests can get into your garage if you leave it open, causing damage or making off with your property. With the garage door open, even just a few inches, small animals can get inside your garage and potentially make a home there. Thieves are obviously interested in taking your things for themselves, and a small bit of leverage may be all they need to gain access to your garage, and maybe even the rest of your home. 

Leaving a garage door partially open can also strain a traditional garage door's mechanisms and tracks. This continuous application of pressure on the tracks can wear out components. Springs, door rollers, and pull cables can potentially fail prematurely, locking your car in and requiring a costly garage door repair bill. 

A better solution to increase airflow in your garage is to install a fan to keep air moving and run a dehumidifier to extract the humidity from your garage air. Keep clutter to a minimum inside, offering better airflow, and if possible, let your car cool off in the shade before bringing it inside. A hot car will just add more heat to an already-warm garage.

The downsides of leaving a garage door open, even partially so, seem to outweigh the benefits. You might save a few bucks on your electric bill by leaving the garage door up a foot or so, but all of that gets thrown out the window if your yard tools get stolen, or a spare bag of dog food gets invaded by a pack of hungry raccoons. Crack at your own risk.