Garage temperatures.

ran

Senior Member
This summer my garage (5 yr old house, attached two car garage) is hitting over 100 inside. Grabbed a can of spray something, it was empty. Less than a yr old. No windows, just the heat will destroy stuff? I get winter snow here also. I pulled out my electric test gear. I am new to temp extremes. What else should I pull out? standard Cabinets will not help with temp I guess. ideas? thanks guys/gals.
 
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when you look at my location, you will assume I must have some great solution for a hot garage. Nope, we are now in our third summer here, and I've looked but no fix yet. Right now we are hitting 114-117 outside most days, above 90 overnight, so the garage is HOT. When I want to work out there at this time of year, I run a fan, but still hot. Some people use portable "swamp" coolers (blow air through water), I tried a small portable - did not help much, and was a hassle to keep water in it. Also, does not solve what you and I are after, want automatic ventilation.

I've looked and hunted. If you don't care about cost, check out garage fans at this link. One good hint from that site - any exhaust will also need vents cut to allow air to enter. I considered putting an attic style exhaust fan in the sidewall then hooking it to a thermostat to trigger at high temp. Problem with those fans is they have no screens or shrouds for safety since they are mounted in attic where nobody would be near them. I considered adding screen inside and outside, but then the whole contraption would be much thicker than the wall cavity.

I'll be watching this thread to see if anyone has any better suggestions.
 
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A garage attic fan would work great, probably fill the attic access. I guess I am lucky facing the morning sun. My concern is what I store in the garage. nothing like candles, but ready to go thru all my boxes and look for damage. will spray cans die? good idea to store weed & feed somewhere else? these kind of ideas. (too bad the attic access is over my '07 SE. thanks!
 
You can try R-44 insulation up there. There is a product called CoolSeal that I used to apply to mobile home roofs. It comes in 5 gal buckets and rolls on. It reflects the suns heat back into the atmosphere. Works very well and also provides excellent hail protection. If your garage has windows, use solar screens on the windows. This is black nylon screen. You can see out, but others cannot see in. In 100F + I can stand under one and not feel the sun's heat.
 
my garage faces west and has 5 windows across the top of the garage door. it has been upwards of 120 on a few days. but for the most part our summer has been pretty cool so it hasnt been bad. i had some paint stored in there and i was trying to dry it out and it took a few days, the other cans of paint have been ok so far. i just open the garage door to vent it out a bit, come winter time ill be glad i face west.

but to answer your question, no i dont know of anything. it would have to be a real good fan to clear that out i would think? i have an attic but not ready to put some attic fan in there yet.
 
Its 100 outisde and inside right now. Attic insulation,? because there is none. Not sure if I had a bad can of paint or what. would you guys store ammo in .30 cal cans -vented, in this garage? new concern. Good day to debadge the rear of my '07 SE.
 
I really don't think you will have any problems with storing stuff. Ammo will not even come close to going off in those temps. Electrical equipment will also be ok unless it specifically states that they must be kept in a cooler environment. Pressurized cans and tins are the only thing I would be remotely concerned about. Just keep them stored close to the ground and inside a cabinet of some type. 100° is certainly not an extreme, it may be little uncomfortable for us humans, but its not going to cause issues for possessions (beer excluded :) )

If you can afford it I would strongly recommend you in get some good insulation for the garage ceiling/attic area. Do you have a dropped ceiling? I think you can get tax credits for installing insulation in your house too, because it is a 'green' style home improvement. Also, planting trees and shrubs around the house is a great way to provide shade for the garage and the entire house. Shade = free cooling.
 
I could do the insulation in the garage attic myself. After the summer is over. Thanks for all the ideas guys, new here to these extremes. I will have to check if the walls are done. Always surprised that garages are not usually insulated. Can't be a 'fire code' ?? have to check NFPA72.
 
one comment on insulation - it decreases the rate of thermal transfer, but does not prevent thermal transfer. So an insulated garage will still get hot because there will still be thermal transfer. Insulation saves energy in a cooled house for summer, or a heated house for winter, but will not do much if the garage is not cooled. First thing we have to do is ventilate out the hot air.
 
one comment on insulation - it decreases the rate of thermal transfer, but does not prevent thermal transfer. So an insulated garage will still get hot because there will still be thermal transfer. Insulation saves energy in a cooled house for summer, or a heated house for winter, but will not do much if the garage is not cooled. First thing we have to do is ventilate out the hot air.

That is correct. A cheap method would be to install hip and gable vents. I love the blow in white fibreglass insulation (not cellulose). I can hold a hand full of it and aim a propane torch at it. I will not feel the heat. It will not burn. It forms a 1/16" layer of glass at those temps. I had a DOE contract for 2 years in Texas weatherizing high energy consumption homes. This is what the gov't made us use. Best of all, it is itch free.
 
The roof/attic has vents. The Garage ceiling is not insulated. The 2 car garage door is not and the morning sun really warms things up. 109 today. Just checked, the walls are not insulated. Attic Rat in my younger years, ran a lot of low voltage wires. In this case, not sure how much a ceiling mounted fan (blowing into the attic) would help. thanks guys, great ideas.
 
hello again; I think everyone's posts above show that they will know this caution, but thought I'd post in case anyone else reading may not be aware.

Must be careful if venting from garage to attic. The drywall meets a building code for fire block between garage and house. Remember that big sources of gasoline are usually parked in the garage, so that fire block is important. The fire block will slow progress of any fire from garage to house - that can give enough time for occupants to escape. This is one reason that the garage to attic vents that I linked in my first post above are pricey, because they are fire rated and have automatic closing mechanism that detects heat from any fire.
 
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Just another thing I noticed. There is no Fire Wall between the garage and house attics. I have seen this in most newer homes I have worked in the last 25 years. just a note. thanks all. ran
 
one comment on insulation - it decreases the rate of thermal transfer, but does not prevent thermal transfer. So an insulated garage will still get hot because there will still be thermal transfer. Insulation saves energy in a cooled house for summer, or a heated house for winter, but will not do much if the garage is not cooled. First thing we have to do is ventilate out the hot air.
Yeah, thats a good point. One other thing insulation does though, is block radiant heat from surfaces that are exposed to the sun. I would say that a fair proportion of the heat that ran is experiencing is from this. I have a double attached garage at my place with no heating or cooling, but it is fully insulated all round except the door. I experience full sun in the mornings and up to about 3pm and I have never felt like the garage is too hot or even hotter than outside ambient temps. The inside walls are not even warm to touch, so there is no radiant heat making the temp higher.
 
any updates?

Screen type venting work at all for you? I have seen some commercial products designed to let you work in your garage with a screening type material. You have to find a way to clear out the daytime heat-thus at nighttime you need to be venting out the heat and capture the cool air. Not sure about the security aspect of your situation...

We have a detached double car garage and all the interior walls were unfinished when we bought the house. We have used plastic packing peanuts to fill up the wall cavities. A 4 x 8 sheet of plywood with a 6-8 inch gap at the top allows us to fill 3 wall studs at a time with packing peanuts, small pieces of (hard) styrofoam and plastic bottle caps that the recycling center will not take. The weight of the bottle caps poured in as a top layer helps to compress the packing peanuts a bit and meets my standard of cheap (free) insulation. Note: do not use the new eco friendly plant material (typically soybean) packing peanuts or you will have a sticky mess inside your walls. If there is even a hint of moisture whatsoever you will learn to tell the difference in texture and feel of the peanuts very quickly.

We only do this in the Hollow wall sections. Check your local building codes if there is electrical wiring present in a wall section. So far we have completed 2 of the 3 (south and west) walls and it is noticeably warmer in the winter and cooler in the summer. Have not yet gotten to the roof area.Would still like to do the north wall but have run out of free plywood and free packing peanuts with my present underemployment.

We used plexiglass for one wall section so I can use it as a demonstrator for folks who do not believe packing peanuts slide easily and compact down the wall studs. A simple thump on the wall every so often will readjust and compact them a bit more-we open the top plate again and pour in some more. A bottom opening section allows us to use a few at Christmas time or for other mailing needs-closing the recycling loop.The main purpose was to keep packing peanuts out of the landfill and second to insulate the garage.

Solar powered roof fans sound ideal for your application. They are a bit more expensive of course, but the tradeoff is no increase in your electric bill.

Stay in touch if I can assist any of you with such a project. The email notification system of this forum is non existent and I may never find this thread again....

The R value of such insulation is not as good as fiberglass or blowin obviously.

But again it is free....This is my side business called Recycle Assisters-and the motto is we can help recycle most anything but not your sister...

Otherwise you need to employ more traditional shading methods...a properly placed tree even if it needs to go in your neighbors yard is an investment in their property for your benefit.
 

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