Ventilation Idea for Garage in Hot Summer

[soonerbrink]

Hello! I am new here, so hopefully this is the right place and has not already been addressed extensively....

Backstory:

I live in Oklahoma and have a 3 car garage which gets extremely hot during the summer (especially with 2 cars parked inside). I am looking for a cost effective way to ventilate the garage (pull cool air in and draw hot air out).

Idea:

Cut a new soffit vent and route duct through the attic to an air inlet in the ceiling of the garage on the east side. Install a solar powered vent on the west side of the roof directly above the garage and route duct to an air inlet in the ceiling on the west side of the garage. Due to the slop of the roof the duct should only need to be a couple feet. However, due to the angle of the roof, I don't think there is enough clearance between the soffit and where the garage is framed out to accommodate duct work for the inlet on the east side. (30 second paint picture drawn below)


Other Thoughts: (not necessary unless you are really intrigued or have extra time)
The garage walls and ceiling are finished, but not insulated. The garage doors have insulated panels. There is no side door on the garage to open and help create air circulation. Even with the doors open in the summer, there isn't any wind from the North, so there isn't much circulation. If I try to wait to work on projects in the evening with the garage doors open, I turn into the all you can eat mosquito buffet. Air conditioning is too expensive and not practical. I sometimes leave the cars outside, but if I need to take the cars in the evening it's not fun getting into a hot car. Also, I thought about leaving the garage doors open, but there have been theft problems associated with this in the neighborhood. I have seen the mesh doors that would keep out bugs and keep down theft, but there would still be no air circulation with these.
In the picture, the airflow is optimal because the unsightly fan would be on the side of the house without the entrance, and the air is pulled in off the cool bricks, not the hot bricks facing the west. However the way it is setup, with my work area on the west side, by the time the airflow enters, the air warms up by the time it gets to me. Either way, air flow from the outside in the evening is better than no airflow.

Conclusion:
As you can tell I have thought about this a lot; however I am looking for any ideas/suggestions/input before spending the time and money in case there is some serious flaw or a better way.

 

[soonerbrink]

Image

 

[pseudorealityx]

As long as you understand that the 'best' you'll ever do is get close to ambient temperatures, then that's fine. If you've got room, bring your 'inlet' duct down to floor level.

As far as keeping it cool, the 'right' solution is to add insulation.

 

[soonerbrink]

As long as you understand that the 'best' you'll ever do is get close to ambient temperatures, then that's fine. If you've got room, bring your 'inlet' duct down to floor level.

As far as keeping it cool, the 'right' solution is to add insulation.

Exactly the kind of feedback I was looking for. I plan on finding a fan that turns on when the garage temperature is above the external temp, and then shuts of when it is cooler in the garage. Not sure if they make them like his or if I need to find a switch with two thermostats that you can program.

With the garage walls finished, above ground storm shelter, and shelves around them, the insulation is just too much work, for not much benefit considering my situation.

I would like to put the duct at floor level, but really don't want to tear up the brick on the house, so soffit will be my first route.

Thanks for the input!

 

[rharman]

We have 3 gable fans to help clear the hot air out of the attic.

An insulated garage door will help you.

 

[cspcrx]

I struggle with this also with my fully insulated garage. Seems to do a great job of holding the heat from the cars in. I leave for the morning and its 102 to 104 degrees inside it. I have two vents on one wall, code required for gas water heater. There is a company that sells a special fan that mounts in the celling to draw the air up into the attic. It includes a pair of large vents that go into your garage doors. Might work for you.

 

[LS6 Tommy]

I struggle with this also with my fully insulated garage. Seems to do a great job of holding the heat from the cars in. I leave for the morning and its 102 to 104 degrees inside it. I have two vents on one wall, code required for gas water heater. There is a company that sells a special fan that mounts in the celling to draw the air up into the attic. It includes a pair of large vents that go into your garage doors. Might work for you.

You do realize it's a code violation to exhaust into an attic? It's also a bad idea in a room with a gas fired appliance...

Tommy

 

[cspcrx]

No i did not. There is a gas heater in my attic so not sure what the issue would be?

I have not done one in mine, i found it while searching for a solution. I find just opening the attic stairs helps alot with the heat.

 

[soonerbrink]

A couple concerns I was thinking of.

The powered vent would need to be on the side with the work area, because it gets sun in the evening to power the vent, and I wouldn't want to pull in air off the hot bricks on the west side of the house in the evening.

So thinking about this. The cool area would enter, heat up as it goes over the cars, and then through the work area, then exit. So cool air would never make it to me. I suppose some air flow is better than no air flow, and it would eventually cool down.

The other thought is... do I need to seal off the water heater door. As it looks, the water heater closet has an empty pipe that leads to the attic, then another pipe that leads from the water heater out the roof. I presume the pipe that leads to the attic is an air inlet for air circulation? Or the closet is designed to pull air from underneath the water heater door and flows up to the attic so the air doesn't get stale? Regardless of what this is for, if I don't seal off this door, the powered vent might pull air from this area, and pull hot air from the attic, rather than the inlet on the other side of the garage?

Does that make sense?

 

[LS6 Tommy]

No i did not. There is a gas heater in my attic so not sure what the issue would be?

Generally, attic power ventilators don't cause any issue with natural draft heaters because there is other cross ventilation in the attic. If the unit is "sealed" and uses 100% outside air for combustion, an attic fan is not an issue. Code does not allow any exhaust system to discharge into an attic or crawlspace. It can cause overdrafting of any natural draft unit in the attic or crawl space, and any harmful gases or vapors exhausted into those areas can be forced into the living space. If the exhaust fan pulls from the garage, there is possiblity of car exhaust fumes, fuel fumes, etc. grtting into the living space. If there is a natural draft heating unit in the area served by the exhaust fan, it can backdraft and the combustion gases forced into the living space.

Tommy