Removing Heat

[Binrat]

come on down to texas, where we move the 110 degree air from outside into the garage to cool it off! unfortunately for me someone (P.O.) built the shop facing southwest and the 4pm sun just burns right into the shop. I offered to buy my neighbor a tree, but that will take years to grow enough to help.

I agree with the others, seal off the lower part with anything you can. check the home depot or lowes for the cheap miscut half sheets of drywall or plywood.

 

[Falcon67]

They're not a good insulator of stopping the radiant heat.

The big problem, I've established, is no ventilation whatsoever in the roof. Radiant heat comes in, stays trapped, and heats up the garage so much it's uncomfortable. Outside temperature is 80 but inside the garage is 100+. Air is moved through the windows/doors fine but that does nothing to stop the heat radiating down from the hot trapped air mass in the trusses.

HD sells some cheap attic fans for about $90 each. Put one in each gable behind a vent and set the thermostat - included - at 90ish. That should pull out the heat. I use one to vent fumes out of the shop . It's a 1600 CFM unit, ,works real good.

Here I use passive - eve vents and 5 passive vents (9" diameter) on the back of the shop roof. I've got under $1K in insulation and OSB on the ceiling (960 sq/ft) and it's well worth it. I may well change that to a ridge vent after a while - there is still a lot of heat that gets trapped up there.

FWIW - it's 105F here today. The underside of the OSB in the house will be around 130F. The underside of the radiant OSB in the shop will be 100~110 and the outside of the west wall will hit 130F easy. Shop will stay in the 80s all day with just the passive venting and R13 in the attic.

If you want some heat - We'll be at the drag strip all weekend (2 day race). I'd expect to see the starting line temp here get to around 150. We'll see. We are gonna fry, then die.

 

[Smiliesafari]

I installed a 2x4 grid drop ceiling in my garage. Built a hot wire foam cutter and cut 2" ridged foam board to ceiling panel size. It solved two problems. I didn't have to buy insulation and the foam board was white with a vinyl coating so I didn't have to paint. The lighting is good also.

 

[tylernt]

I installed a 2x4 grid drop ceiling in my garage. Built a hot wire foam cutter and cut 2" ridged foam board to ceiling panel size. It solved two problems. I didn't have to buy insulation and the foam board was white with a vinyl coating so I didn't have to paint. The lighting is good also.

Nice!

 

[Larosa]

you need to find some solution for this try to construct some chimney or ventilation into it

 

[TheEquineFencer]

Solar powered exhaust fans will work. I have a customer that uses ones made for this application for use as area fans to cool her livestock in her barn. http://www.celestineridgealpacas.com/Contact_Us.html
Contact them, they will tell you where to get them. They have a heck of a warraty too.

 

[CNGsaves]

Show us what you're starting with . . . . pics of garage interior would help.

 

[77thor]

Solar Powered Attic Fans - http://www.allsunsolarproducts.com/soatfanali.html

 

[benjammn]

point here is to remove the heat and cause a thermal removal of the heat from the roof. capping off the roof joints and making a path for the heat to leave the space is what is called for. even some thin 1/4" sheeting will suffice with this. the roof venting and eves along with a few roof fans will effectively remove the majority of heat. adding some insulation on the underside of the sheeting will add more to creating less heat in the space. this would be the cheaper alternative.

 

[adpostel]

Not to HiJack the thread, but I have the same type garage, non insulated 22x25 Detached with exposed attic/trusses. My plan is to simply keep the garage below 90* when I am not in there. When I am working in there, I raise both garage doors, and use an oscillating fan to keep cool. I currently have Radiant Barrier Decking on the roof, and a whirly bird vent. My walls are covered with painted OSB, but no insulation. I have one window that has a screen, and stays open. I have the Matador Garage Door Insulating kit on the way, which I am hoping will help prevent heat radiation from the garage doors that face the sun up until about noon or 1 pm. My next step is to install a window fan unit in the only window. My question is, should I go with one of the thermostat controlled double fan units (seem kinda cheap), or should I go with a Whole House Window Fan that would bring in outside air, and hopefully push air up through the whirly bird. Am I on the right track? I live in Houston, and you know how sweltering it can get around these parts. Thanks. I ask in this thread, because I think the OP may benefit from the answer, hopefully. Thanks.

 

[benjammn]

I think that a lot of people don't understand a lot about thermodynamics. You need an inlet of sufficient size and an outlet of >= to inlet for good heat exchange. Almost to a positive inside the room. We want to have more cool air coming in than hot air going out.
http://www.science20.com/i_can_get_...ome_save_heating_cooling_costs_thermodynamics
So most of the time I see too many people without enough air flow to remove the heat that is in the space. Plus, not enough insulation to help keep out the heat that is causing the problem to begin with. Most structures have some kind of passage way for hot air to move through wall spaces to keep things cooler on the inside.

 

[tylernt]

My next step is to install a window fan unit in the only window. My question is, should I go with one of the thermostat controlled double fan units (seem kinda cheap),

I used one of those for a few years in my house. They're noisier per CFM of air moved (or to put it another way, they move less air per db of noise), but it's held up fine for me. It's nice that it blocks up the rest of the window, so the air you just brought in doesn't immediately turn around and go right back out the corners of the same window.

or should I go with a Whole House Window Fan that would bring in outside air, and hopefully push air up through the whirly bird.

I have the same type garage, non insulated 22x25 Detached with exposed attic/trusses.

Do you plan on installing a ceiling so the WHF can be installed in the ceiling, or are you just going to put the WHF in a wall and leave the attic/trusses exposed? I think the WHF will work in a wall with an exposed attic, but it will be less efficient than in a ceiling. Attics are naturally always hotter (solar gain), so separating it from the rest of the garage is always a win for comfort. But I don't know how big of a win we're talking here, especially since you have a radiant barrier... so it may not make a lot of difference in your case.

As for exhausting air, benjammn is right. If you have a 30"x30" fan, you need somewhat more than 30"x30" of exhaust. So if you have -- or can add -- soffit or gable vents, the whirlybird can exhaust some of the air and the other vents and take care of the rest. If the whirlybird tried to move 5,000CFM all on it's own, it would probably hit about 5,000RPM.

 

[xtremek]

I'm in a similar situation as far as funds go, probably tighter. I bought plastic and stapled it to the under side of the rafters. I cut up little squares of cardboard so the plastic wouldn't pull through the staples. I left a 10'x10' area undone and put 2'x2' flooring underlayment boards (had them laying around) on the resting on the bottom of the rafters. Not a tight seal, but it helped a ton and cost me about $20

 

[adpostel]

Oh, I'm sorry, I was a little unclear on the whole house fan. What I was wanting to install was a Whole House Fan Window Unit, In the only window I have, hoping that bringing in the air from the outside would push the hot air out of the whirlybird vent on the roof......

 

[CNGsaves]

Oh, I'm sorry, I was a little unclear on the whole house fan. What I was wanting to install was a Whole House Fan Window Unit, In the only window I have, hoping that bringing in the air from the outside would push the hot air out of the whirlybird vent on the roof......

That will work, especially if you pull in "cool" air at night so that space starts off the morning at coolest temp possible. There in Houston, TX the humid air will be tougher on you than the OP in upstate NY.

Friend had an old squirrel fan from HVAC unit, and it was mounted in window and pulled in nice cool air at night.

Stealing a marketing line from another product . . . .
. . . . If you want to cool the air, you have to MOVE the air !!

 

[adpostel]

OK, cool, so my Matador Garage Door Insulation kit just arrived. I'll be installing it tomorrow. I have a Bionaire 2300 window fan on the way. It is cheap, but there aren't really any other better made window fans that will work with my window. Once I install all of that, I am gonna keep a close eye on the temps inside, and I'll update yall.... I hope it works better than nothing.