Before moving to Arizona in 2009, I lived in Michigan. I had a job where I worked outside and was used to the cold weather. Once I moved out here, while going to college, I worked for a company where I was installing satellite service and was often in attics during the heat of the summer.  

Attics in the summer heat out here can exceed over 160 degrees. And garage workspaces normally don’t fare much better when it is 115 outside. I can tolerate the heat, but I’m not a big fan of working in that kind of energy-zapping temperature if I don’t have to. So, with my own garage and my own project timelines, answering the question of “What you can do to cool your hot garage?” became of interest to me.  

A sweltering hot garage can hinder your projects and keep you out of your garage entirely during the summer months. Extreme temperatures can also make it completely unusable as storage space. Cooling your hot garage can be done in several ways, ranging from portable solutions to more permanent upgrades. Here are 10 ways to make your garage space cooler.   

1. Improve Airflow in Your Garage

One way that you can help cool your hot garage is by decluttering to allow air to circulate. If you have boxes, bins, and tools stacked to the ceiling, know that those things are also absorbing heat and hindering air from flowing around your garage. By purging some of the things you don’t use and getting a better storage system in place, your newly opened room will overall feel cooler.  

 Installing drywall to cover any bare studs can also improve airflow, as this eliminates the pockets in the walls that can cause the circulation to slow or stagnate. You can read more about that here: “9 Reasons to Drywall Your Garage.” 

2. Use the Weather to Your Advantage

Some of my favorite times while working out in the garage are when I can wake up early and get projecting before the sun comes up. This time of day is cooler and (with the kids not up yet) can be very peaceful and productive.  

Use this early morning time to your advantage when cooling your garage. When the weather is cooler, open the garage door and let the cool air in. As the sun starts to rise, close the doors and lock in the cooler air and love it for as long as it lasts.  

You can use the same idea in the evening when the sun starts to set. Out here in Arizona, you can expect 110-115 degrees (43-46 degrees Celsius) during the late summer afternoons. When the sun starts to set behind the mountains, you can quickly feel the temperature drop by 10-15 degrees. Use the cooler outside air to your advantage, open the doors and cool your garage area. 

3. Evap Coolers 

If you make your living out in your garage, or you are someone that spends a ton of time out in the shop, an evap cooler might be your jam. A friend of mine has one of these and they can be great for lowering the temperature to a work-friendly level. In dry areas like Arizona, an evap cooler can cool your garage by up to 30 degrees. 

I will add that the summer conditions and location of your home will be factors to consider before you purchase one of these. If you are in a dry, hot climate, you are good – the return on investment will likely be favorable. If you are in a more humid area, you might need to consider the effectiveness of an evap cooler versus some other options that are on the market.  

4. Misting Fans 

While they tend to leave a little more water on the floor, misting fans are another great option to cool a hot garage space. The sizes and style vary from standing fans you would normally see in a house, to ceiling-mounted fans that some restaurants with patios use. 

Much like evap coolers, the misting fan evaporates water, cooling your garage in the process. Also, like evap coolers, humidity will be a factor that you will need to consider before you make your purchase.  

Misting fans tend to be decently priced and can usually just be a quick item to pick up at the hardware store if you need something right away.   

5. Ceiling Fans 

If you are looking for a more permanent option for cooling your hot garage, a ceiling fan can be a great investment. Humidity, unlike the last two options, is less of a factor if you are simply using a fan to move air.  

Since you are combatting more heat than your insulated home, we suggest that you look at a shop fan that can move more air than the typical living room fan. There are several fan options when it comes to ceiling fans, and the size of the fan needs to be a major factor when determining on which one will best suit your garage. We would recommend a 52” to 60” fan, just make sure you have enough space for the blades. 

6. Garage AC Unit 

One of the more expensive options for cooling your hot garage is to purchase a garage AC unit. There are, again, several different types of AC units that can work, with a variety of features. 

In most situations, a portable AC unit might be enough. You will need to determine if the unit is enough for the overall cubic footage of your garage, and the size and price will reflect the output needed from the unit you purchase.  

From my experience with these portable AC’s, the unit will tend to run continually while it is operating. Unless your garage walls and door are insulated, heat will radiate into the garage while the sun is up, causing your garage to feel hot. You might need to repoint this type of AC unit to keep the cool air on you if you move around the garage when you are working, but these systems can greatly increase the comfortability and will cool that hot garage enough so you can get some work done.  

Another option is a window AC unit (if your garage has a useable window). These types of units are easy to find and have some different pros and cons versus the portable ac units just mentioned prior. With window units, you will not have to worry about where the hot air is going to go that the AC unit expels. But you are limited by where the unit can be installed and the direction the cool air is going to initially blow. 

The last AC unit type to explore is to install a permanent split system air handler. If you are going to make this type of investment in cooling your hot garage, it is a good idea to fully insulate your garage first to keep your energy costs as economical as possible.   

7. Install Attic Ventilation  

Another option to consider when you are trying to cool your hot garage is to install attic vents. As with my Arizona heat example, attics can climb to 160+ degrees Fahrenheit during the summer. If you are able to lower the temperature in your attic, even if only by 10-30 degrees, there is less heat that is radiating into your garage through the garage ceiling.  

Attic vents do just what the name implies – they provide a means of escape for the built-up hot air, cooling the attic, and ultimately the garage underneath. 

8. Install a Garage Exhaust Fan

My dad is a big proponent to using exhaust fans in his garage, and after seeing what he has accomplished, I can now say that I am a believer.  

First, when the sun goes down and the outside air begins to cool, you can use the exhaust fan to push the hot garage air into the attic, forcing the garage to bring in the cooler outside air to cool your work area. 

Second, if you are not conditioning your garage air, the exhaust fan can circulate the garage and attic air by pushing the air up and into the attic and out the attic vents. This has two benefits, one, it will push the hotter air, stuck in the attic, out the attic vents. Two, the negative pressure caused by the exhaust fan will cause air from outside to come in the garage and provide some circulation. 

Third, and this one is more for the rest of the house, on cooler evenings where the house is warmer than the outside air, rather than using the AC to bring the house temp down, you can use your exhaust fan. If you find yourself with a night like I am describing, close up the garage, open the entry door for the garage going into the house, and open the house windows. 

These exhaust fans can move about 400 cubic feet of air a minute. If you close the garage and open up the house windows, it won’t take very long to replace the stagnate air from the house with the cool evening air. 

9. Insulate Your Garage and Your Garage Door

Insulating your garage and garage door are some of the most effective means of controlling your garage temperature. Rather than just trying to cool your hot garage, insulation can also help all year round with keeping the heat in during the winter months.  

When it comes to insulating your garage door, purchasing a garage insulation kit is the most effective for you, your time, and your wallet. Insulating your garage door is a quick project, normally taking an hour or two, and just a few tools so you can cut to fit. Check out our article on “How to Insulate Your Garage Door” for the step by step process and recommendations. 

For insulating your garage walls, there are some things that you need to consider prior. If your garage is finished, meaning drywalled, you will probably want to look I not having a company spray foam between the outer wall studs. If the garage has not been finished yet, batt insulation will most likely be the most beneficial and cost-effective for the DIYer. 

For your garage ceiling, the options are slightly different. If you are a fan of the spray foam, and/or are needing the space up in the rafters for storage, you might want to have a company come and spray foam your roof. This will keep the insulation above your ceiling joists allowing for additional storage if you do or are planning, in using your attic as additional storage. 

Batt insulation is also an option for your ceiling. This type of insulation is normally more expensive than other DIY insulation jobs but is very simple to add.  

A third option for ceilings is cellulose insulation. Basically think recycled newspaper, that you can blow over the ceiling drywall of your garage.  

No matter which insulation type you decide to go with, installing garage ceiling insulation will greatly reduce heat transfer and will drastically help cool your hot garage.

10. Add a Radiant Barrier in the Attic 

If you are out here in the valley of the sun or another area that can have brutal summer heat, the final way we are going to discuss in this article on how to cool your hot garage is by using a radiant barrier. 

Some types of insulation might come with it, so check and see when you are making your purchase. In most cases though, this will be another addition that you can add to help lower the temperature in your garage. The radiant barrier makes your attic look like a room full of aluminum foil. For insulation purposes, it looks as if aluminum foil and bubble wrap had a baby since the material looks like silver bubble wrap. 

Radiant barrier is useful in the attic since it will reflect a big majority of direct heat from entering the garage. Another place that we suggest using a radiant barrier is against your garage door since this is another large surface that can face the sun and otherwise has little to combat the radiant heat entering your garage. 

Conclusion 

Getting your garage to a cooler temperature may involve using a number of these ideas in tandem with each other. Adding things like insulation or a garage exhaust fan may be out of your scope for the time being. But things, like opening the garage in the morning and getting a standing misting fan may be temporary solutions until you can make some more permanent upgrades. Whichever direction you choose to go, know that you don’t have to settle for a hot space in the dead of summer! Reclaim your garage from the extreme heat by changing a few things at a time. With some tweaks, you will find your storage options more friendly and your workspace more productive.