Garage is hot - ideas?

[meburdick]

Hi, all.

Recently moved into our home and I'm looking for ideas to help keep the garage a bit cooler in the heat of summer.

The garage door (16') faces NW and there is a room "behind" the garage that would block the direct sun. To the South / SE of that room is a lot of trees but there is plenty of at least filtered sunlight that hits the back wall of the home. Direct sun hits the roof. Above that room and the garage is attic space. Over the last few weeks, daily temps have been anywhere from about 75 to 90 (ish) and the garage temp is generally at least 5-10 degrees above the outside temp but it does seem to peak a little over 90 degrees. This is with no cars in the garage at all because we are still in the process of moving in and all of our "stuff" is in the garage in boxes while we work through it.

In the very near future, one of the cars that will be in the garage is my V8 convertible which gives off a LOT of heat after being driven and I'm looking for any ideas on how to possibly provide some sort of venting for this space to keep the temp from getting so high. Anyone have any thoughts on a simple, easy way of venting the space? Pic attached shows the orientation of the property for reference. There is a window on the side wall that faces NE.

 

[ez-duzit]

Install the largest fan-operated vent fan practical, drawing the hot air out of the peak. Insulate the roof.

 

[meburdick]

Thanks for the thoughts... I am not sure how I might be able to make this happen, though, since the space over the garage is attic space that also continues above the living space behind the garage. The entire area over the garage and living space is insulated as you would expect attic space to be, and there is a gable vent as well. It's all your typical "convection" type ventilation that any attic space would have. Also, it isn't ungodly hot in the attic space (warmer than the garage, but nowhere near as warm as the attic space above the rest of the house and that space is over second floor living space as opposed to first floor living space).

 

[DrinkMan]

We use window fans in our garage to keep it ventilated. Keeps the fumes from the cars out. Critical to the heat in the garage are two things 1) tint on the windows of the garage door (we dropped our garage temp about 15 degrees by putting on the tint) and 2) insulated doors.

 

[meburdick]

We use window fans in our garage to keep it ventilated. Keeps the fumes from the cars out. Critical to the heat in the garage are two things 1) tint on the windows of the garage door (we dropped our garage temp about 15 degrees by putting on the tint) and 2) insulated doors.

Thanks... Any thoughts on using a fan with only one window? I don't want to increase the ability to break in, either. Also, no windows in the garage door, AND there's a shade covering the window on the wall...

I'm trying to figure out if there's something within the house that is "adding heat" to the garage because the orientation and such just makes me feel like it shouldn't be getting as warm as it does in the first place. I have a 5 cubic foot chest freezer in a slightly oversized 2 car garage. It honestly doesn't cycle a lot because it's really well insulated, so the amount of heat being added by it should be small (plus, this was in a small one car garage for the past two years and that garage was seldom as warm as this one, and NEVER this warm with no car in it).

 

[Hohn]

I've just resigned myself to sweating profusely. Ranch style house, 3 car attached. Lots of insulation over garage and a high ceiling. South facing doors.
It's tolerable mostly, but at certain times of year, I just can't.

 

[rancherbill]

There are no fans / ventilators showing on the pic.

You can install ride type or some of the several styles below.

https://www.google.com/search?rlz=1...bkcCr0Q0pQJegQIDxAB&biw=1154&bih=526&dpr=1.66

https://www.google.com/search?rlz=1...dIsCoUQ0pQJegQIDRAB&biw=1154&bih=526&dpr=1.66

https://www.google.com/search?rlz=1...eqxDDwQ0pQJegQIEhAB&biw=1154&bih=526&dpr=1.66

 

[ez-duzit]

... I have a 5 cubic foot chest freezer in a slightly oversized 2 car garage...

There's your heat source.

 

[meburdick]

There's your heat source.

Sorry, but no.

This exact same freezer was in a one-car garage along-side a computer cabinet. WITH my convertible in the garage, the temp would hit 90 on a hot day. Now, it is in a two car garage with no other heat source (including no cars) and a garage door that faces NW (previous garage faced W for full afternoon sun on it, no windows). This garage get close to 90 on hot days.

In looking in the attic space much more closely, it appears that there is not enough insulation along the joists and there may well be a fair amount of heat infiltrating from above. I will have to get the thermal thermometer out and see what the ceiling temps are like in the garage... Ultimately, it may be a case of needing more insulation in the attic space.

 

[WisJim]

Hard to give advice without knowing things like location, kind of construction and materials, amount and kind of insulation in walls, etc.

 

[Jinks]

First, insulate the garage door!! Next, if price is an issue, add a fan in the window or wall to pull air through a slightly raised door. Of course the most effective method is to add a mini split.......

 

[chris142]

Put a swamp cooler in

 

[meburdick]

First, insulate the garage door!! Next, if price is an issue, add a fan in the window or wall to pull air through a slightly raised door. Of course the most effective method is to add a mini split.......

Thanks...

Garage door is insulated (to some extent, anyhow). I've thought about adding active cooling (mini split or even window unit) but electrical costs are exorbitant here. I did discover that there is not enough insulation above the garage (some areas are missing it entirely) and that may well be the simplest course to reducing the temps. The temp in the attic space is definitely hot enough that it could be radiating downward through the ceiling.

 

[meburdick]

Put a swamp cooler in

Interesting idea, but... New England... when it's hot, it's often also very humid. I don't know how well it would work.

 

[DrinkMan]

If you have an insulation issue above the garage, that needs to be taken care of first. And you are correct, swamp coolers are not very effective in humid areas. If you do fit a window fan, you can simply lock the lower window in place (either a "stick" on the ends preventing it from opening or some other means - I've drilled holes from the lower window to the upper window and pushed in some finishing nails that act as deadlocks).

When you use a window fan to blow air out, just figure out where it will get the makeup air from (leaks around garage door or around door entering house). Here is a highly rated fan: https://www.amazon.com/dp/B08R6B9RD1/?tag=atomicindus08-20

 

[meburdick]

If you have an insulation issue above the garage, that needs to be taken care of first. And you are correct, swamp coolers are not very effective in humid areas. If you do fit a window fan, you can simply lock the lower window in place (either a "stick" on the ends preventing it from opening or some other means - I've drilled holes from the lower window to the upper window and pushed in some finishing nails that act as deadlocks).

When you use a window fan to blow air out, just figure out where it will get the makeup air from (leaks around garage door or around door entering house). Here is a highly rated fan: https://www.amazon.com/dp/B08R6B9RD1/?tag=atomicindus08-20

Thanks - Agree all around. I'm already looking into possible options from the State to help with evaluating the insulation and even assistance on adding more.

Once the insulation is addressed, I will reassess and see where I'm at (although, by then, the cars will be in the garage as we're working our way through the "stuff" to make room for the cars). I will have to be considerate of changes in temperature AND the presence (or not) of cars when I'm at that point as well. The past residence would simply be left to its own for the heat levels to fall overnight, but the garage was -under- the living space as opposed to here where it's on the same level.

 

[DrinkMan]

What does the state have to do with it? Just run to the big box and buy rolls of R30 or greater and put it in. Do it early morning. If it is blown in, that may be messier to deal with. But the missing areas seem easy to just put in a few rolls.

 

[meburdick]

What does the state have to do with it? Just run to the big box and buy rolls of R30 or greater and put it in. Do it early morning. If it is blown in, that may be messier to deal with. But the missing areas seem easy to just put in a few rolls.

Energy audits and public programs for increasing the efficiency of your home. They are state run programs and offer a variety of things to reduce power use like LED lights, insulation, rebates on Energy Star appliances, etc. You bring them out for an audit and see what programs you qualify for.

Rolls of R30 come in 25 foot lengths for about $45. I would need about 13 rolls to do the entire area above the garage which is not a trivial cost - especially if the energy audit provides any for free or at reduced cost. Further, the state program that provides rebates for insulation of an attic actually want you to achieve R38.

 

[FredWanaker]

such a simple question. Make sure the attic is insulated with R40 or better - you say it is. Make sure the walls are insulated and that you have an insulated garage door. That will end the hotter than outside problem. While it will be hot in summer and cool in winter, the extremes will go away. If you pull a car in then the engine heat will go into the garage. Sometimes I open the garage door six to eight inches and put an 18" fan blowing air outside. That will get rid of the car heat. But it also leaves an opening for pests to get in like rats cruising or the neighbor's cat. On hot days when i am working in the garage I open the door into the house and put a 24" fan blowing into the garage. It pushes conditioned air into the garage and warm air back into the house to be cooled by the AC. Works well but it will cause the bill to be a little higher because you are conditioning another 400 or so square feet.

 

[meburdick]

such a simple question. Make sure the attic is insulated with R40 or better - you say it is. Make sure the walls are insulated and that you have an insulated garage door. That will end the hotter than outside problem. While it will be hot in summer and cool in winter, the extremes will go away. If you pull a car in then the engine heat will go into the garage. Sometimes I open the garage door six to eight inches and put an 18" fan blowing air outside. That will get rid of the car heat. But it also leaves an opening for pests to get in like rats cruising or the neighbor's cat. On hot days when i am working in the garage I open the door into the house and put a 24" fan blowing into the garage. It pushes conditioned air into the garage and warm air back into the house to be cooled by the AC. Works well but it will cause the bill to be a little higher because you are conditioning another 400 or so square feet.

Portions of the attic are well insulated, but I've found areas that are not. That's definitely my starting point.
The door is insulated, the walls "should" be but I have no way to actually confirm. Even if they aren't, it's really only one wall that isn't.

My interest is in making the garage so that it isn't constantly 80 degrees and above, even first thing in the morning, especially since we just don't get weather that's constantly warm enough to warrant that in the summer. As I am able to free up space in the garage, I will continue to check with the infrared thermometer to see where warmer areas are. Right now, the ceiling seems to be running about 5 degrees warmer than the temp in the garage itself and it's night time. I'll check it again a few times this week as temps will be climbing into the 90's.

As you mentioned, I am trying to avoid having the door open unless I'm actively doing something in the garage or driveway - keep out pests and the "looky-loo's", especially right now with so much of our stuff basically on display.

 

[nadogail]

A sheet metal roof over your present roof, with a well ventilated air gap between the two will reduce the solar heat build up in your garage.

Ready Service Ammunition Boxes and Shipboard Pyrotechnic Lockers have been protected this way for over 100 years.

 

[duneslider]

If you aren't conditioning the garage you WILL end up with the temps pretty much the same as ambient outside temps. Sure, if you can cool it down and night and then shut it up in the morning it might make it a while before the temps climb but the garage will eventually end up the same as the outside temp. Insulation and air sealing just slows that process a bit. The better sealed and insulated the longer it will take to reach ambient.

 

[meburdick]

If you aren't conditioning the garage you WILL end up with the temps pretty much the same as ambient outside temps. Sure, if you can cool it down and night and then shut it up in the morning it might make it a while before the temps climb but the garage will eventually end up the same as the outside temp. Insulation and air sealing just slows that process a bit. The better sealed and insulated the longer it will take to reach ambient.

Same temps as ambient outside would be fine. I'm running well above during the hotter days, though. Right now, the garage is 79 and it's 69 outside - first thing in the morning.

 

[tool_scrounge]

A lot of houses in Southern California have a few small 6x12? vents on the bottom of the garage walls. Not very useful on their own, but add a $20 centrifugal fan from and old furnace to one vent and you change change the air out of your garage every few minutes. Just add a course screen on the fan to keep people’s fingers out of the fan blades. If desired, you can add a thermostat to turn on the fan when it gets too how in the garage. Works very well.

 

[duneslider]

Same temps as ambient outside would be fine. I'm running well above during the hotter days, though. Right now, the garage is 79 and it's 69 outside - first thing in the morning.

That's because it is closed all night and is holding the hot temps in while it cools down outside. If all you want is to keep it the same as outside a vent on one side and fan on the other will accomplish this. Its been 100 at my place lately and on the weekends when I am working around the yard the 100 degree garage isn't that nice but it is what it is. It does stay a little less than ambient and if I have all the doors open and a fan on the air flow feels nice.

I had a neighbor who did some hobby painting in his garage and he installed an electric damper low on one side and then another on the opposite side up high with a fan, all tied to a switch so when he turned it on both dampers opened and the fan turned on. Worked really well at moving air through the garage.

 

[meburdick]

I had a neighbor who did some hobby painting in his garage and he installed an electric damper low on one side and then another on the opposite side up high with a fan, all tied to a switch so when he turned it on both dampers opened and the fan turned on. Worked really well at moving air through the garage.

A lot of houses in Southern California have a few small 6x12? vents on the bottom of the garage walls. Not very useful on their own, but add a $20 centrifugal fan from and old furnace to one vent and you change change the air out of your garage every few minutes. Just add a course screen on the fan to keep people’s fingers out of the fan blades. If desired, you can add a thermostat to turn on the fan when it gets too how in the garage. Works very well.

These are similar to each other and good ideas. The ideal flow would have intake on one side and outlet on the other... Since my two exterior walls are adjacent to each other, I'll have to see if this might be feasible in some way.

 

[dcg9381]

In the very near future, one of the cars that will be in the garage is my V8 convertible which gives off a LOT of heat after being driven and I'm looking for any ideas on how to possibly provide some sort of venting for this space to keep the temp from getting so high. Anyone have any thoughts on a simple, easy way of venting the space? Pic attached shows the orientation of the property for reference. There is a window on the side wall that faces NE.

When I built my home, I build to address this. I put a simple "attic fan" in the garage on a temperature switch. When you drive in a heat soaked car and it hits X degrees in the garage, the attic fan turns on and vents to the outside.

I'm sitting up north right now, the structure I'm in also has a fan (I'll have to find the reference) that can be set to run based on humidity / temp. In theory, you can program it to pull in cool air from the outside under certain conditions... These systems are typically designed for tightly insulated homes (foam insulated) and designed to do moisture control in colder climates... Hot climate, just do what I did above to deal with the cars.

Even in a northern climate in a building that's insulated between R40-R60, it gets hot upstairs this summer w/o HVAC.

 

[FredWanaker]

those small vents are to allow any leaked natural gas to escape before it causes the big bang. They were never meant for cooling. If the garage is hotter than outdoors by 10 degrees early in the morning, sounds like there is a lot of heat soak, and additional insulation will help with that unless you wife or kids are sneaking in with a hot car at 4AM.

 

[toyotadriver]

Too many factors to give a solid answer. We know nothing about the place you moved from and how it compares to your new place.

Bottom line is....insulate, ventilate, condition. In that order. If more insulation doesn't fix it, then you need to ventilate. Powered ventilation will always beat passive ventilation. If ventilation isn't enough to make it as comfortable as you would like, then your only last option is to condition the space by installing AC.

 

[Glemon]

I used to live in a house with a three stall facing south, no insulation in the garage. It got very hot in the summer, probably 10-15 degrees above ambient.

I now have a three stall facing North, R15 in the roof, insulated walls and doors It still gets very hot in the summer. Hotter than ambient by the end of the day, passive vent. I notice a hot car really speeds up the process and makes it worse.

It will stay cooler if we have had a sudden heat up from cooler temps but doesn't last long. I was hoping the insulated garage on the north side would stall a little cooler, I have medium tan shingles and I think a lot comes from the roof. Next step is a fan and try to pull some cool air in at night and keep it there during the day.

Anyway, my experience with garages is that they tend to go hotter than ambient temp.

The insulation does help in the winter. Generally 20 degrees warmer than ambient at all times.

 

[Jackfre]

When I lived in MA and no cooling in the house we used a whole house fan. Once the sun got a bit low the windows opended and the fan through the evening/night would reduce the temp in the house by bringing in somewhat cooler night air and cooling the mass of the building. Panasonic makes a good WHF. In CA my shop had no cooling. I would work until it hit about 92* and then bail for the day. In ‘20 I covered the S facing roof with solar collectors. Not only did it offset my electric bill year round, but it greatly reduced the interior summer temp in the building. Insulate, ventilate, cool. Also, park the beast outside until it cools off some then bring it in.