Garage door vents
 

I am considering putting a vent in the right and left lower corners of my garage door to reduce heat in the garage especially during the summer months. Will doing this really substantially reduce heat build up in the garage. For example, if the air temp is 95 will the vents keep the garage below 100 degrees. I have good venting in the roof and I plan to keep the retractable stairs to the garage attic down during the summer. Please let me know if you have experience with this.

My garage had the vents in the garage doors, door insulation, and the fan in the attic which pulled air thru the vent in the garage ceiling. I thought the system was a complete waste of money. All it did was pull hot/humid air from the outside. It is a west facing garage. If you want the garage at a comfortable temperature to be able to spend time in it the only good solution is to insulate the attic and garage doors, then add a mini split.

A total waste of money and it will weaken your garage door. My neighbor installed an attic fan and those garage door vents. Within a month or so, he turned it off and never used it again. You will get hardly any air flow through the vents. Also, you should not leave the retractable stairs down because that will compromise the fire rating of your garage.

Will just bring more humid air, better off without vents in the door.

Why not just leave your garage door open a bit in the morning when the air is coolest? Agree, no reason to spend money on this.

As other have said, they work the opposite since they pull hot air off the driveway.

Waste - O - Money

Added the vents in the door, insulated the garage door, added the garage to attic vents, and 2 solar attic vents. My attic temperature has dropped a huge amount and my garage is significantly cooler. I get a very nice draft running through the garage and you can feel the draft in the attic. They must have messed up my installation since it doesn't work for anyone else.

In our house and most of the houses in our neighborhood garages do not have windows. Have you thought about adding a window(s). This can get rid of the hot air and add light to the garage.

If you put vents in your garage door and lower your stairs you are creating the perfect chimney. If you should have a fire in the garage it will spread into the attic before you can even dial 911. And don’t be surprised when your insurance company tells you to pound sand.

This is the 2nd house we done that in and the garages have been noticeably cooler during the hot part of the summers; pushes the hot air out of the attic also.

I have a fan and the two vents you speak of, and they work fantastic.. also try a auto roll down screen door .. the best of both worlds ( and of course get estimates) quality matters

If youre going to do anything, do the roller screens.

Cutting into the garage door will weaken it - not good when next hurricane type storm comes throug.

I get morning sun on my garage door, put up a DYI garage door insulation kit. It helps a lot.

Do Nothing. In a couple of years you won't care.

Why concern yourself with heat in your garage useless of course you spend time out there
with a hobby of some sort.
In that case spend the $$$$ and insulate doors, ceiling, and add it's own AC.

Exactly. Park your car and go into the air conditioned part of your house.

hot air rises, so why put vents at the bottom?

if you want to reduce heat build up that's not really the correct way. Don't know why everyone does these things.... These attics are NOT properly vented. They require more vents and also insulation over the garage. These are all you need to do. But as I say it's your house to mess up , so do whatever.

try a few in the ceiling of the garage...the closable type,so you can adjust

In the middle of summer, will you help cool your house if you open windows to let the nice hot humid air in? You don’t let air in your house during the summer, I wouldn’t let it in the garage either. I have insulated the garage doors with some improvement. You do have to watch out for making your garage doors too heavy for the garage opener when insulated them

I did the same—added an attic exhaust fan. What was I thinking? About $700, and I used it at most five times. It can’t cool your garage below the temp of the outside air, so that might be 85°! If you leave it on all night and cool your garage down to seventy, when the sun shines on the door the temp zooms up in minutes. Morning or afternoon sun will turn a steel door into an oven, and half an inch of insulation inside the door won’t make much if any difference. (Two inches of styrofoam on the outside would help, but that isn’t allowed.) If you drive your car, then park it in the garage, it will also heat your garage above the outside temp for hours. A mini-split AC can work, but it has to work hard to overcome a hot car or sun on the garage door or leaks along the edge of the door. I’ve been told by people who work here to figure around $10,000 to install one!

If you rebuild classic cars in your garage or have a home workshop you use a lot, it might be a good idea. If not, a fan in the garage can blow air on you, and that helps, and you can open your garage door when you work in the garage. I have battery operated saws and sanders and drills and a cart where I can put stationary tools and use them in the shade in the garage or on the driveway as needed. But I seldom need to do that for more than fifteen minutes at a time. Some work I can do in the house.

Vents in the garage ceiling would violate the fire code.

Why anyone puts those ugly vents in the doors is beyond me. Anyway, hot air rises and the vents in the bottom are ineffective. If you spend a great deal of time in the garage, I would recommend a split and that will cost you about $6 or $7,000, but would be worth it. I insulated the door and, although does not bring the temperature down to house levels, does make a difference.

Vents
 

I'm a tinkerer and DIY-er my garage door faces north so not much sun and if I am home it is usually up. If my doors faced any other way I would probably insulate them

Does it help to open the hatchway to the attic over the garage? Will hot air flow up and out better? Wondering.

Insulate the door and keep it shut. The night air is cooler, the insulation will keep it cooler longer. Venting only works when there is cooler air outside to bring in.

Mini Splits are wonderful. I helped a neighbor install one on a manufactured home lanai and golf cart garage combo. It was a no name unit and I learned a lot working with him. It did a great job.

The vents in the door look like a real shoemaker deal and I doubt that that update with an attic fan would satisfy me.

Krazorback gave your way a green light! Kenswing pointed out the chimney effect!

Mini Split is the way to go.

As I re-read all the posts, I guess it is necessary for you to clarify your intent.
If your intent is to keep your garage in the 70's to spend significant time in there, than the posters who say why bother, unless you put a minisplit are probably correct.
If your intent, like mine, is to keep your garage from being 10-15 degrees hotter than outside, then the door vents, and vents into the garage do make sense in my opinion. I have a refrigerator in my garage, and I was expending a great deal of energy and wear and tear on it trying to keep up with 100 degree temps in the garage, when it is only 80-90 outside. Now, my garage is at least as cool as the outside. The garage door vents are at the bottom to bring the coolest air from outside into the bottom of your garage and then create a draft going up into the attic. If you only intend to put the vents in the garage door, that probably wouldn't do much, since it doesn't create an air flow. If you put the vents in the top of the door, it would exhaust out air in the garage that is hotter than the outside, but only if makeup air is available. You definitely do not want that makeup air to be the cooler air drawn out of your house.

HVAC people told me not to open the garage ceiling door, it interrupts the airflow from other areas of the house that need to pull air in from outside to cool the whole house.

I had Kalo's install a mini-slit and insulate the attic. It is great! I keep the temperature moderate, and cool when working in the garage.

Probably also makes a difference which way the door is facing.

radiant barrier insulation
 

You might consider installing radiant barrier insulation on the garage door. I did this on our garage door. Radiant barrier insulation is now code for roofs in Sumter County. It works by reflecting heat back out. If you get sunlight on your garage door in the afternoon, this would likely reduce your temperature in your garage. I did this in mine as I have 2 full size freezers with a maximum temperature rating of 110F. My goal was to keep the garage under 95F. Since installing the radiant barrier insulation, my garage has never reached the 95F mark. I have a thermometer in the garage that keeps track of maximum and minimum temperature as well as maximum and minimum humidity.

Door vents
 

I have had three vents put in. My garage doors. The doors insulated and a vent fan installed in the ceiling. There is a significant amount of air flow thru the vents but remember the air coming in will never be cooler than outside. I believe the attic is much cooler than before also.

Garage door vented high on on side, low on other side. Radiant barrier installed in attic and on inside of garage door. Ceiling vent in garage. Peak summer temperature within 3 degrees of outside ambient.

No....that is not true, if done properly. Vents alone will do nothing and as stated above, leaving the attic stairs open is against insurance and fire code. We installed "cool my garage" ceiling fan. The fan runs on an electric motor, is controlled on and off by the temperature in the attic, and has an emergency damper that will shut the opening in the ceiling down should a fire start. The approximate 12" exhaust fan pulls the air through the garage and up through the attic to the roof vents. My fan comes on when the temperature in the attic reaches 100*F and stays on until the temperature is lowered to 100*. The vents in the garage door are necessary to allow air flow through the exhaust fan to the ceiling vents. I have 4 vents in the lower panels of my double door. It also allows my to keep my attic stairway closed to meet fire and insurance requirements. Cool My Garage - #1 Garage Fan | Garage Ventilation | Attic Fan

Thank you
 

Thanks everyone for your thoughts and advice on this topic.

I've been here over 10 years and have had numerous friends move here over varying times so I have seen and heard a lot of discussions about insulating garages. All the more recently moved people are concerned about their garage temperatures but it seems as time goes on, people think less and less about it and their ability to control it. I would suggest you do nothing, as nothing seems to work that effectively and as time goes on, you will find a hot garage is really just part of living in TV and is not that big of a deal.