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Do you live in one of the southern states where it is hot most of the year? Should you even be concerned about garage insulation? Yes. Garage Door Insulation has an important role to play even in Hot Climates. It will certainly help keep your garage cool without you spending a fortune on energy bills!
Garage Door Insulation in Hot Climates should use Reflective Material to block out Radiant Heat from the sun. Painting your garage door White and managing garage door “open times” will also help in keeping your garage cool with no additional energy costs.
In this post I explain why your garage is getting so hot, the steps that you can take to keep your garage cool and the additional equipment that you can install to further cool your garage cheaply.
Read on as I have a lot of helpful advice on the best garage door insulation and ways to keep your garage cool if you live in a hot climate.
Why Is My Garage So Hot?
A garage may actually be the hottest place in your home. There are a few reasons why a garage tends to be hotter than other rooms.
Garage Door Exposed Area
Without doubt, the garage door is the biggest door that you have in your house. A standard one car garage has a 8’X7’ door, while a standard two car garage has a 16’X7’ door.
Garage Door Materials
Steel is the most common material used for making garage doors, followed by aluminum. Both are metals and are good conductors of heat. They quite easily conduct the heat from outside into the garage.
Vinyl and fiberglass are sometimes used to make garage doors. They do not conduct heat as well as steel & aluminum, but are not insulators by any chance. Solid wood is the most heat insulating garage door material but it is not as commonly used.
Moreover, most garage doors have glass window inserts in the panels. Glass is a poor insulator of heat as well.
A garage door that faces south would have the hot sun beating down on it most of the day.
Garage Door Usage
A garage door gets opened several times in a day and it’s not just for the cars. In many homes, the attached garage has become the preferred route of entering or leaving the house.
Need to mow the lawn, the lawn mower is in the garage. Want to go cycling, the bikes are stored in the garage. So much so that the garage entry door may lead directly to the mud room. Actually you could even put your mudroom in the garage.
The more the garage door opens, the more the hot air from outside gets into the garage. Before you know it the garage temperature is moving up pretty close to the outside temperature.
Garage Walls & Roof
While the garage door is the biggest culprit, a fair amount of heat comes in through the walls and the roof.
- The detached garage will have all three walls exposed to the elements unlike an attached garage.
- The detached garage, in all likelihood has nothing between the garage ceiling and the garage roof. An attached garage may have an attic or some other room above it.
Will Insulating My Garage Door Keep It Cooler?
Insulating your garage door will certainly help in keeping your garage cooler, as it has a large surface area that is letting in the heat from outside. But which is the best garage door insulation for hot climates?
Heat flows from a high temperature area to a low temperature area, just like water flows from a higher level to a lower level.
The Three Ways of Heat Transfer
There are three ways in which heat flows.
Conduction is the process when heat moves from the high temperature zone to the low temperature zone through the solid material between the two zones.
Convection is the process in which the air in contact with the high temperature zone moves and takes the heat away to the low temperature zone.
Radiation is the process when the heat moves from the high temperature zone to the low temperature zone through electromagnetic waves such as visible light, UV rays and infrared rays.
Choice of Insulation Depends on the Climate
In cold climates garage owners have to insulate so that they do not lose the garage heat to the freezing cold outside. This heat loss is mainly due to conduction. Convection does play a role but heat loss due to radiation is miniscule.
So in cold climates the primary role of garage door insulation should be to stop heat loss by conduction.
In a hot climate, the garage will gain heat mainly from the sun’s UV radiation falling on the garage doors. Heat gain through convection comes into play when the garage door is open. Conduction plays a relatively smaller role.
So in hot climates the primary role of garage door insulation should be to stop heat gain by radiation.
What Is The Best Garage Door Insulation For Hot Climates?
So, now you know that you have to take a somewhat different approach. The Best Garage Door Insulation For Hot Climates need not be the same as the best garage door insulation for cold climates.
Paint Your Garage Doors White
You may wonder what the color of the Garage Door has to do with insulation. Turns out, a lot!
The color of an object is the color of the sunlight that the object is reflecting and sending back to your eye.
Black absorbs almost all of the light and reflects next to nothing. The absorbed light radiation converts to heat.
On the other hand white reflects almost all of the light and absorbs next to nothing. As there is very little absorption of light radiation, a white garage door will get less hot.
This is why white clothes keep you cooler during summer. And this is exactly the reason why white paint on a garage door will act as radiant insulation for hot climates.
I recommend using Rust-oleum Marine Topside (Gloss White) Paint, available on Amazon for your garage doors. I know it is designed for boats. Which is why it is fantastic for garage doors as well! The gloss white color will reflect the harsh sunlight and keep your garage cool.
In addition, Rust-oleum Marine Topside (Gloss White) Paint, is UV Resistant, Weather Resistant, Highly Durable and will retain its gloss for a long time.
Use Garage Door Reflective Insulation in Hot Climates
In hot climates, the focus of insulation of a garage door has to be on blocking as much of the solar radiation as possible. This is achieved by sandwiching a layer of air entrapping material between reflective films.
There are two brands which are very popular and get good reviews; REACH and REFLECTIX. Take your pick.
Reach Barrier (3009) Garage Door Insulation Kit, available on Amazon, works well in hot climates. The key features are:
- Reflective Insulation & Bubble Barrier Technology blocks up to 95% of Radiant Heat
- 2 Layers of 5/32″ Barrier Bubble are laminated between 2 Layers of Reflective Polyethylene
- The Kit includes 8 Pre-Cut Panels, which are very easy to install
Reflectix (BP24050) Bubble Pack Insulation, available on Amazon, comes as a roll rather than a Kit. The key features are:
- It reflects up to 97% of the Radiant Heat
- 2 Layers of Double Bubble Aluminum Foil are bonded to a tough layer of polyethylene. The total thickness is 5/16″
- Comes in rolls that can be cut and are easy to install. It can be used on any surface such as garage door, drywall garage wall, attics
- Has excellent vapor barrier properties for below grade installation, or garage sub floors
Better Management of Garage Door “Open Time”
This is not exactly a garage door insulation but it will help regulate the inward flow of heat in hot climates. Helpful advice on how to better manage this is:
- Install a side door in one of the garage walls, if possible. Use the garage side door as far as possible so that you do not have to open the larger garage door.
- If above is not possible, consider using the front door or another door that leads into the house, rather than the garage.
- Park your car outside, after you return from a drive, for some time so that the car can cool down. (Hot cars and car engines can continue to radiate heat into the garage, if parked inside immediately).
- Open the garage door in early mornings and late evenings, when the outside has cooled down. The warm air from the garage will move out and be replaced by the cooler & fresher air. Use a garage door screen to stop pesky pests and flying insects from getting in.
How Can I Cool My Garage Cheaply?
Insulation is a passive form of keeping the temperatures in your garage lower than that outside. However, it may still not make the garage a comfortable place, if the outside temperatures are above 90 degrees. So what can you do to cool down your garage to an acceptable level, without breaking the bank?
Air Circulation can help Cool you Down
Still air can be stifling. Don’t you feel a lot better when there is a gentle breeze blowing. The reason is simple. The movement of air over your skin helps evaporate moisture on your skin. This results in a slight cooling of your body.
Gentle motion is uplifting and calming at the same time. Just having gently flowing water or air near you has this magical effect. Movement is a sign of life and the human brain is hard-wired to respond positively to such signals.
So installing a fan, be it a ceiling fan, a pedestal fan or a table fan will certainly help you cool down as you work or workout in the garage. They all help in increasing the air circulation on your skin.
Fans are both cheap to buy and cheap to run.
An Exhaust Fan will Not Help Cool a Garage in Hot Climate
However, the use of an exhaust fan in a garage will not help cool the garage, in a hot climate. An exhaust fan will only push out the air in the garage (which is cooler than the air outside). The cool air will be replaced by hot air from outside.
So do not use an exhaust fan for cooling the garage. You may, however, use it for ventilation and removing bad odor, if any, in the garage. This may be required at times.
Mist Fans & Evaporative Coolers are Very Effective in Dry, Hot Climate
Mist Fans & Evaporative Coolers are affordable and work especially well in climates which are dry & hot. This 4-in-1 Multifunctional Air Cooler from HighLandy is moderately priced. The bladeless design makes it very safe. It is also energy saving and eco friendly.
Check it out on Amazon.
If you have a large 2 car garage then you will need something bigger. You can check out the evaporative cooler from Hessaire.
Window Air Conditioner will Cool the Garage
A window air conditioner will actually cool the garage. But then window air conditioners do not come cheap. There is the initial cost of the equipment, to which you have to add the cost and trouble of installation.
Installing a window air conditioner is a lot of work. You need to cut a hole in the wall, the size of the window air conditioner (typically 30″X30″). And then you need supports, electrical wiring, etc.
Not the best of options, in my opinion.
Mini Split Air Conditioner is Even Better
If you can spend some money and want your garage to be a cool retreat, then installing a Mini Split Air Conditioner is the way to go. Since you are in a hot climate, you need not buy a fancy model that cools, heats, dehumidifies and ventilates.
Just get one of the basic models from Amazon such as Pioneer Diamante Series Ductless Mini-Split Air Conditioner Inverter Heat Pump Full Set with 16 Ft. Kit. It is important to get the model which has sufficient cooling power for your needs.
The downside of a Mini Split is that it is a bit pricey. For half the price or less you can get a BLACK+DECKER BPP06WTB Portable Air Conditioner with Remote Control, 10,000 BTU, Cools Up to 250 Square Feet, White from Amazon.
Use Solar Panels on the Garage Roof
You can eliminate the need to pay the utility company for cooling your garage if you install solar panels on your garage roof. Find out more about this environmentally friendly option by reading my earlier blog post Will Solar Power From Detached Garage Really Save Money?.
Use the Heat of the Sun to Beat the Heat from the Sun!
Use Roof Vents
Garage roof vents are another way of keeping your garage cool. Hot air always rises up. If you have a roof vent then the hot air can exit and fresh, cooler air can be drawn in from windows or garage wall vents!
Thank you very much for reading the post. I do hope you found it informative and useful.