Best Way to Cool a House Garage to Work In

[10scoachrick]

Interestingly, the town houses we're hoping to buy(fingers crossed) has a door to the side patio and then an entrance to the kitchen off the other end of the patio. In other words, no direct access to the garage from the house, so no option of pulling some cool house air into the garage. A horribly inefficient way to cool the garage; but I sure have tried it a time or two. What is needed is an exhaust fan up high(say the last panel in the door).

[pmiranda]

Originally Posted by CptnRn

I have a lot of experience with building codes and do not believe that installing an AC vent into the garage is a violation. You definitely do not want to return air from the garage into the house, as that cold draw gas, exhaust and other fumes into the house. You could install a fire rated damper to make sure, but typically the only fire separation between a house and a garage is a 1/2" layer of sheet rock and an unrated door.

when adding an air supply to the garage, you need to make sure there is someplace for the air to exhaust, a window or crack the garage door o pen a small amount. Leaving a door open from the house is not a good idea as it will draw all the warm air and possibly noxious air from the garage into the house.

Uh, I think the residential code is unambiguous:

R309.1 Opening protection. Openings from a private garage
directly into a room used for sleeping purposes shall not be permitted.
Other openings between the garage and residence shall be equipped
with solid wood doors not less than :1 3/ 8 inch (35
mm) in thickness, solid or honeycomb core steel doors not less
than 1 3/8 inches (35 mm) thick, or 20-minute fire-rated doors.

R309.1.1 Duct penetration. Ducts in the garage and ducts
penetrating the walls or ceilings separating the dwelling
from the garage shall be constructed of a minimum No. 26
gage (0.48 mm) sheet steel or other approved material and
shall have no openings into the garage.

It might have been common to see a cheap unrated door between the house and garage (my old house had one when we bought it), but it should not pass inspection now and it's not a good idea. Similarly, a vent connecting to the garage should fail inspection and is a bad idea. You don't want an open vent to allow gasoline vapors, hydrogen from charging batteries, or any other fumes into the ductwork.


If you're not worried about inspections, I'd feel OK about a vent that is fire rated and automatically closes when the AC is not running (You can usually tap into the thermostat wiring to run a 24VAC solenoid). You will probably find that your home AC system isn't going to move enough air for the extra vent, so at the same time I'd add an inline booster fan, which can be switched on from the thermostat wiring as well, using a 24VAC controlled relay to switch the 120VAC motor. Have a switch in the garage (or even fancier, a motion sensor) to disable the whole thing when you're not out there.

But the first step should be insulating the walls and doors. An exhaust fan to get rid of the heat when you bring the car home would help, too, but if you're like me I leave the door open until the car cools off.

You should search on Garage Journal's forums to see what other folks have done. (And I bet they'd like to see some pictures of your Falcon as much as I would!)

I just open the overhead door and sweat :-)

[10scoachrick]

Originally Posted by pmiranda

I just open the overhead door and sweat :-)

Fortunately, the headboard project was delayed until today...a fair bit cooler out there! Way humid, but cooler.

[cBach]

I never understood the need for a climate controlled garage, unless you live up north where engine block heaters are required, then a heater for the garage is mandatory.

I do a fair amount of work in the garage, but you tend to get used to it after a while. Take frequent trips inside for some cool A/C and plan to go for a swim when your body feels like a wet blanket. This is Texas, you're gonna get hot, no ways around that.

That being said, if you want A/C on yourself then consider either a swamp cooler, which will work effectively when it's 100 outside, or a portable A/C with a long hose that goes outside. Then you can effectively move the blower around to where you are and just aim it on yourself. For the winter, those portable radiant heaters work fine.

Putting a vent to the garage from the main house system is a bad idea for several reasons. While the air is blowing, you'll need the garage door at least partially opened, to equalize the pressure. That will prevent contaminated air from the garage blowing in. All I can think of for this is dollars just blowing out your garage door..

However, and this is the key, when the A/C shuts down, the pollutants from your garage tend to rise and have a convenient way to get into the duct system, all the way back up to the main unit. Then the A/C kicks in again and your son/daughter's bedroom now has paint thinner, gasoline, carbon monoxide, and all those horrible pollutants in it. Is it really worth your comfort to give your child cancer?

It's like in the winter, when we're not using the dryer, cold air enters the dryer and it's freezing in there, because the air is no longer blowing out, it just becomes an entry point for air. When the dryer is on it's not a problem because of the airflow. Likewise for the duct you are installing into the garage, it's an entry point into the house for pollutants, even if the vent is closed, because those vents are never airtight when closed.

[BatWing]

2 box fans strategiacally placed to where the hot air is blown out while the decent cool air is blown on me while I work..