Hot garage

[Northerner52]

Would replacing the wood panel with a simple screen allow heat to rise up into the attic and out the eves?

[Michael Charles]

Would replacing the wood panel with a simple screen allow heat to rise up into the attic and out the eves?

Yes it does make sense that the heat in the garage would rise up and naturally connvect out but you would also need fresh air to help move it (make up air)

You might want to contact someone like a contactor or even the fire department because that wooden panel might be a fire blocking panel to contain or suffocate a potential fire. Just a thought to consider and it does make sense considering how air tight houses are designed these days. No air, fire doesn't spread so quickly.

[retiredguy123]

Would replacing the wood panel with a simple screen allow heat to rise up into the attic and out the eves?
The original panel to the attic is typically drywall, not wood. But, replacing it with a screen would be a bad idea. You would be violating the fire code and would allow a fire in the garage to easily spread to the rest of the house. Also, I don't think it would help to cool the garage very much because the temperature in the attic is higher than the temperature in the garage.

[davem4616]

Would replacing the wood panel with a simple screen allow heat to rise up into the attic and out the eves?


nope, ya don't want to do that...it's against the fire code

more than a few folks in TV have installed screens that cover the garage door opening....adding an 'exterior' ceiling fan over your workbench and opening the window in the garage would be a few other ideas to cool it down

[REDCART]

We used Solar Guys to install an exhaust fan in the garage ceiling controlled by a thermostat This fan was designed with a fire sensor that would close the damper if necessary. The thermostat was set to 95 on, 90 off. We also added 4 vents in the insulated garage door. Except for moving air, it did nothing to lower the temperature in the garage. We had an East orientation.

A neighbor with a North orientation consistently has garage temps that are no warmer than the outside temp. They have radiant barrier insulation in the attic and an insulated garage door. So it may be a combination of both orientation and insulation. IMHO skip the ceiling exhaust fan.

[Toolong]

Our front faces west and we had terrible heat during summer afternoons. Solar Guys installed garage door insulation that was a great help. It somehow reflected the heat as opposed to traditional installation.

[JohnN]

We used Solar Guys to install an exhaust fan in the garage ceiling controlled by a thermostat This fan was designed with a fire sensor that would close the damper if necessary. The thermostat was set to 95 on, 90 off. We also added 4 vents in the insulated garage door. Except for moving air, it did nothing to lower the temperature in the garage. We had an East orientation.

A neighbor with a North orientation consistently has garage temps that are no warmer than the outside temp. They have radiant barrier insulation in the attic and an insulated garage door. So it may be a combination of both orientation and insulation. IMHO skip the ceiling exhaust fan.

We have the Solar Guys fan and I'm pleased as punch about it. It's still hot, but it's the same temperatuire as outside since that's the air it draws in. It is ventilated and a LOT cooler than it'd be without any air movement.

[rjm1cc]

The tempeture inside my garage only gets a few degrees hotter than the outside temp in the middle of the day. Might measure your temps before you do anything. If you are going to be working in the garage also measure when you will be using the garage. But yes the garage is cooler in the morning and hotter at the end of the day.

[merrymini]

I insulated the garage doors myself using insulation purchased from Texas Garage. Easy. And it brought about a reduction of temp of about 20 degrees. My garage faces east. Do not like the vents in the doors and do not want to make additional holes in my roof for fans and such which may have limited value. I can live with this.

[crash]

Would replacing the wood panel with a simple screen allow heat to rise up into the attic and out the eves?

Most of the heat is coming from the attic so a bad idea. Insulate the garage ceiling and install a radiant barrier you will get 15 degrees cooler.

[MandoMan]

Would replacing the wood panel with a simple screen allow heat to rise up into the attic and out the eves?

The best way to heat up your garage fast is to park your car in a sunny parking lot for an hour or two or drive it a few miles in the sun, then park it in your garage. A ton of hot steel, well over 100° on the outside, will share its heat with your garage interior, and that will take a long time to cool down. If you want a cooler garage, it will help to park your car on the driveway when you come back from your errands and not move it into the garage until just before you go to bed.

[vintageogauge]

Most of the heat is coming from the attic so a bad idea. Insulate the garage ceiling and install a radiant barrier you will get 15 degrees cooler.

Heat rises and there is nothing that will drop the garage temp 15 degrees other than air conditioning.

[davephan]

Has anyone tried to air condition their insulated garage with a split AC unit? I wonder how much it would cost to cool an insulated garage down to about 80 degrees.

[genobambino]

I had a conversation with Munns hvac about something similar, or just leaving the door to the attic open and they said definately don't do that. The soffits are designed to pull air in from around the whole house and out the vents in the roof, when you leave that access door open or screen it your disrupting the entire design for air movement.

[New Englander]

Heat rises and there is nothing that will drop the garage temp 15 degrees other than air conditioning.

:agree:

[tallmanf]

Against fire code

[tbone]

Has anyone had mildew in their garage? I have had mildew show up on a car steering wheel and on various tools with rubber handles. This is after returning from a three month absence during which the garage doors were not opened at all.

Have investigated a fan that fits in between joists to pull air into the attic (create air movement) as well as split air conditioners and dehumidifiers. No decision made yet.

One a/c guy said the problem is lack air movement and suggested running a pedestal fan and to create air movement.

Any help and/or ideas are appreciated!

[midtee9]

I insulated the garage doors myself using insulation purchased from Texas Garage. Easy. And it brought about a reduction of temp of about 20 degrees. My garage faces east. Do not like the vents in the doors and do not want to make additional holes in my roof for fans and such which may have limited value. I can live with this.

Hi, That is a good outcome.....can you furnish more detail on the company you used...
full name, phone, approx. cost?
TIA

[ktierno]

One way to cool the garage is to spray foam to the underside of the roof of your house and over the garage. This will prevent the attic air from heating up and will turn your attic into conditioned space . It will be the temperature that your AC keeps your house and reduce your AC costs by 25 to 30 percent or more. It will extend the life of your shingles and strengthen your home. This will work but is expensive.

[zendog3]

Most of the heat is coming from the attic so a bad idea. Insulate the garage ceiling and install a radiant barrier you will get 15 degrees cooler.a

I don't think this is correct. I have worked in the garage on a hot day. With the panel to the roof open, a stiff breeze blows from the garage up into the roof. I am sure, simply leaving the panel off would soon cool the garage to outside temps. However, after reading this thread, I am also sure that this would be a big fire hazard. in the event of a house fire, the open panel would turn your house into flue or chimney and burn your house down much faster.

[vintageogauge]

One way to cool the garage is to spray foam to the underside of the roof of your house and over the garage. This will prevent the attic air from heating up and will turn your attic into conditioned space . It will be the temperature that your AC keeps your house and reduce your AC costs by 25 to 30 percent or more. It will extend the life of your shingles and strengthen your home. This will work but is expensive.

I don't think that will work at all, you can't block your eve and/or roof vents, you have to get in an out of your garage by opening the garage door, it will never be cooler than the outside temp inside the garage unless air conditioned, would be a big wast of money. When I have to work in the garage on hot days I just run a large box fan to keep the air moving, doesn't cool it off but the movement makes it feel cooler.

[GypsyRN]

Has anyone tried to air condition their insulated garage with a split AC unit? I wonder how much it would cost to cool an insulated garage down to about 80 degrees.

We recently installed a Carrier split A/C system (actually a dehumidifier for permitting purposes) in our garage and a half, and I have trouble keeping the temperature ABOVE 78 degrees...I have the unit set for 80 Degrees, sometimes 81 or 82. So I'm a firm believer that it works. I insulated the attic above the garage myself (in the Feb/March timeframe) with 10" batt insulation (cost me $600ish) and without this, I'm certain that I couldn't have achieved this. Note that I also had a small solar roof mounted attic fan installed by SolarGuys. Why did we do all this? We were tired of the damage that the high heat was wrecking on the refrigerator, stand upright freezer, golf cart, and motorcycle seals. We should have done this years ago!!!

[Topspinmo]

Would replacing the wood panel with a simple screen allow heat to rise up into the attic and out the eves?

You’re garage probably already has vent to attic. Mine close to the Central A/C heat unit. Screen IMO would allow hotter air for the attic into the the garage depending on outside wind pressure? Fan might work to cool the attic from 130 plus to maybe 125 or so. But, IMO nothing but going to cool garage except portable swap cooler or some type of air conditioning. Even window fan won’t bring temperature down but make if feel better on the skin.

[retiredguy123]

You’re garage probably already has vent to attic. Mine close to the Central A/C heat unit. Screen IMO would allow hotter air for the attic into the the garage depending on outside wind pressure? Fan might work to cool the attic from 130 plus to maybe 125 or so. But, IMO nothing but going to cool garage except portable swap cooler or some type of air conditioning. Even window fan won’t bring temperature down but make if feel better on the skin.
There should be no vent that allows air to vent from the garage space to the attic space, unless there is a fire wall separating the attic space above the garage from the rest of the house. That would be a fire code violation. Any vent in the garage should vent air to the outside of your house.

[Topspinmo]

There should be no vent that allows air to vent from the garage space to the attic space, unless there is a fire wall separating the attic space above the garage from the rest of the house. That would be a fire code violation. Any vent in the garage should vent air to the outside of your house.


There one in my CYV, the house has been sold at least 4 times since 2002. No such violations from inspectors maybe depends on county?

[retiredguy123]

There one in my CYV, the house has been sold at least 4 times since 2002. No such violations from inspectors maybe depends on county?
This is an excerpt from the 2018 International Residential Code. I don't know about 2002, but, in my opinion, a vent that allows air to freely move from the garage into the attic would not comply with this requirement. The purpose of the requirement is that, if you have a fire in the garage, you don't want it to spread to the rest of the house.

TABLE R302.6 Dwelling/Garage Separation

Separation Material
From the residence and attics, not less than ½-inch gypsum board or equivalent applied to the garage side.

[Northerner52]

Who did your Carrier work? Thanks for your post

We recently installed a Carrier split A/C system (actually a dehumidifier for permitting purposes) in our garage and a half, and I have trouble keeping the temperature ABOVE 78 degrees...I have the unit set for 80 Degrees, sometimes 81 or 82. So I'm a firm believer that it works. I insulated the attic above the garage myself (in the Feb/March timeframe) with 10" batt insulation (cost me $600ish) and without this, I'm certain that I couldn't have achieved this. Note that I also had a small solar roof mounted attic fan installed by SolarGuys. Why did we do all this? We were tired of the damage that the high heat was wrecking on the refrigerator, stand upright freezer, golf cart, and motorcycle seals. We should have done this years ago!!!

[BostonRich]

After reading this thread I did some searching on the Internet regarding DYI insulating of the garage door. There are several different type kits available for less than $100 bucks for a 9 foot door. People claim it works well and gives you up to a 30 degree temperature reduction inside the garage.

So I am considering a foam panel system from Home Depot (about $65). It seems like a pretty easy project. My door is 12 feet so I would need to double that or split one kit with someone who has the same size door. Check out the videos and let me know if you are interested in splitting a kit.

Access Denied (https://www.homedepot.com/p/Cellofoam-Garage-Door-Insulation-Kit-8-Pieces-Garage-Door-Insulation-Kit-8-pcs/203630159) (Won't let me post link - Look for Cellofoam Garage Door Insulation on the Home Depot site.)

[Topspinmo]

After reading this thread I did some searching on the Internet regarding DYI insulating of the garage door. There are several different type kits available for less than $100 bucks for a 9 foot door. People claim it works well and gives you up to a 30 degree temperature reduction inside the garage.

So I am considering a foam panel system from Home Depot (about $65). It seems like a pretty easy project. My door is 12 feet so I would need to double that or split one kit with someone who has the same size door. Check out the videos and let me know if you are interested in splitting a kit.

Access Denied (https://www.homedepot.com/p/Cellofoam-Garage-Door-Insulation-Kit-8-Pieces-Garage-Door-Insulation-Kit-8-pcs/203630159) (Won't let me post link - Look for Cellofoam Garage Door Insulation on the Home Depot site.)

I could see that helping if sun on garage door in afternoons? 30 degrees? My garage temps never over 100 degrees, probably less than 95 degrees majority of time and sun not shinning on it in the afternoons I don’t see how anything could lower temperature 30 degrees ( which would put it the low 70s or high 60s) other than air conditioning?

[davephan]

We recently installed a Carrier split A/C system (actually a dehumidifier for permitting purposes) in our garage and a half, and I have trouble keeping the temperature ABOVE 78 degrees...I have the unit set for 80 Degrees, sometimes 81 or 82. So I'm a firm believer that it works. I insulated the attic above the garage myself (in the Feb/March timeframe) with 10" batt insulation (cost me $600ish) and without this, I'm certain that I couldn't have achieved this. Note that I also had a small solar roof mounted attic fan installed by SolarGuys. Why did we do all this? We were tired of the damage that the high heat was wrecking on the refrigerator, stand upright freezer, golf cart, and motorcycle seals. We should have done this years ago!!!

Did you have to specify that it was a dehumidifier because the permit would have been denied if you just got the permit as an air conditioner? Or, maybe something in the building code that discourages people from creating living space out of garages?

Do you have any idea how much it costs to air condition your garage? It sounds like a great solution to the garage heat problems if the ongoing operating costs aren't too high.

[Topspinmo]

Has anyone had mildew in their garage? I have had mildew show up on a car steering wheel and on various tools with rubber handles. This is after returning from a three month absence during which the garage doors were not opened at all.

Have investigated a fan that fits in between joists to pull air into the attic (create air movement) as well as split air conditioners and dehumidifiers. No decision made yet.

One a/c guy said the problem is lack air movement and suggested running a pedestal fan and to create air movement.

Any help and/or ideas are appreciated!

If you got that much mildew I suspect you have leak or a/C drain not draining and holding moisture? Something causing the mildew and IMO it not normal? You can look outside see if the A/C drain is draining some where should seed PVC pipe sticking up and draining? You can take panel off you unit and look in at the A coils. Look along walls of garage for any signs of moisture?

[retiredguy123]

After reading this thread I did some searching on the Internet regarding DYI insulating of the garage door. There are several different type kits available for less than $100 bucks for a 9 foot door. People claim it works well and gives you up to a 30 degree temperature reduction inside the garage.

So I am considering a foam panel system from Home Depot (about $65). It seems like a pretty easy project. My door is 12 feet so I would need to double that or split one kit with someone who has the same size door. Check out the videos and let me know if you are interested in splitting a kit.

Access Denied (https://www.homedepot.com/p/Cellofoam-Garage-Door-Insulation-Kit-8-Pieces-Garage-Door-Insulation-Kit-8-pcs/203630159) (Won't let me post link - Look for Cellofoam Garage Door Insulation on the Home Depot site.)
Insulating the garage door will only slow down the heat transfer from the outside to the garage interior. The garage will still get just as hot, but it may take a little longer. But, in the evening, the garage will actually take longer to cool down because the heat transfer will flow from the garage to the outside, and the insulation will slow it down.

My garage has no insulation or ventilation. Right now, the outside air temperature is 96 degrees, but my garage temperature is only 91 degrees. My garage never get above about 96 degrees, even when the outside air temperature is 100 degrees.

[big guy]

There should be no vent that allows air to vent from the garage space to the attic space, unless there is a fire wall separating the attic space above the garage from the rest of the house. That would be a fire code violation. Any vent in the garage should vent air to the outside of your house.

There is one in my house in front of furnace closet, vents to attic, built in 2004, Sumter county.

[retiredguy123]

There is one in my house in front of furnace closet, vents to attic, built in 2004, Sumter county.
I think the attic vent is a code violation of the current building code (see Post No. 26). I have also read several expert opinions that say an attached garage should be isolated from the living section of the house and the attic to contain a fire that starts in the garage. If you have a fire with smoke that occurs in the garage, the attic vent will allow the attic to fill up with smoke and permeate the rest of the house. This is my opinion, but maybe a home inspector could provide another opinion.

[REDCART]

I think the attic vent is a code violation of the current building code (see Post No. 26). I have also read several expert opinions that say an attached garage should be isolated from the living section of the house and the attic to contain a fire that starts in the garage. If you have a fire with smoke that occurs in the garage, the attic vent will allow the attic to fill up with smoke and permeate the rest of the house. This is my opinion, but maybe a home inspector could provide another opinion.

If the home has a gas furnace, could that ceiling vent be a vent from the outside to provide the required air for combustion? I seriously doubt that the building inspector would miss such an obvious violation.

[BostonRich]

Insulating the garage door will only slow down the heat transfer from the outside to the garage interior. The garage will still get just as hot, but it may take a little longer. But, in the evening, the garage will actually take longer to cool down because the heat transfer will flow from the garage to the outside, and the insulation will slow it down.


Yeah but that's when we are in the garage, right? Don't really care about the night.

[yabbadu]

I insulated the garage doors myself using insulation purchased from Texas Garage. Easy. And it brought about a reduction of temp of about 20 degrees. My garage faces east. Do not like the vents in the doors and do not want to make additional holes in my roof for fans and such which may have limited value. I can live with this.

Did the material installed make the door movement any less noisy????

[retiredguy123]

The posts on this thread that claim to reduce the garage temperature by 20 or 30 degrees by installing foam insulation on the garage door are not believable. Right now, at 1PM, the outside temperature at my house is 95 degrees and the interior temperature of my garage is 96 degrees. My garage door faces west and has no insulation on the door. Adding insulation to the door wouldn't change anything. Yet, some posters are claiming that adding an inch of foam board to my garage door will magically reduce the garage temperature to 65 or 75 degrees. I would suggest that, before you insulate your garage door, monitor your garage and outside temperatures during the daytime. If the temperature difference is less than about 5 degrees, the door insulation will be a total waste of money.

[crash]

Heat rises and there is nothing that will drop the garage temp 15 degrees other than air conditioning.

The insulation and radiant barrier prevent the heat from getting in, thus cooler. The inside of the radiant barrier is 15 degrees cooler than the hot side. You can check it out for yourself on the internet just search radiant barrier.

The attic insulation prevents the heat from the attic radiating into the garage.

[crash]

The posts on this thread that claim to reduce the garage temperature by 20 or 30 degrees by installing foam insulation on the garage door are not believable. Right now, at 1PM, the outside temperature at my house is 95 degrees and the interior temperature of my garage is 96 degrees. My garage door faces west and has no insulation on the door. Adding insulation to the door wouldn't change anything. Yet, some posters are claiming that adding an inch of foam board to my garage door will magically reduce the garage temperature to 65 or 75 degrees. I would suggest that, before you insulate your garage door, monitor your garage and outside temperatures during the daytime. If the temperature difference is less than about 5 degrees, the door insulation will be a total waste of money.

I agree with this because most of the heat is coming from the attic. If the temperature is 95 outside the attic is over 140. Just insulating the door will not help.

[Topspinmo]

The insulation and radiant barrier prevent the heat from getting in, thus cooler. The inside of the radiant barrier is 15 degrees cooler than the hot side. You can check it out for yourself on the internet just search radiant barrier.

The attic insulation prevents the heat from the attic radiating into the garage.

How is it going to reduce it below ambient temperature when everything in, around, and above it is ambient at least temperature? IMO it Will NOT reduce temperature below ambient temperature. The garage is not sealed air tight.

[retiredguy123]

How is it going to reduce it below ambient temperature when everything in, around, and above it is ambient at least temperature? IMO it Will NOT reduce temperature below ambient temperature. The garage is not sealed air tight.
It is correct that no matter what you do to the garage, short of installing an air conditioner, you will never get the garage temperature below the outside air temperature.

[hastey001]

:mademyday:It is correct that no matter what you do to the garage, short of installing an air conditioner, you will never get the garage temperature below the outside air temperature.

[fastboat]

Has anyone tried to air condition their insulated garage with a split AC unit? I wonder how much it would cost to cool an insulated garage down to about 80 degrees.
Dreamer!!

[tbone]

If you got that much mildew I suspect you have leak or a/C drain not draining and holding moisture? Something causing the mildew and IMO it not normal? You can look outside see if the A/C drain is draining some where should seed PVC pipe sticking up and draining? You can take panel off you unit and look in at the A coils. Look along walls of garage for any signs of moisture?

Thanks for the reply! There are no leaks or A/C drain issues. The problem is likely that the garage door is often not opened/closed for up to a couple months at a time when I am traveling. Therefore, no air movement.

I have installed a dehumidifier, and it dropped the humidity to my set 55% level and cycles on/off as expected. Also got a 20" box fan to move air when I am working in the garage.

[davephan]

Dreamer!!

That's a strange response. You should go back and read post number 22, then the related posts 27 and 30. There are some people, not many, in Minnesota that heat their garages in the winter. We don't heat our garage in the winters. That certainly can't be cheap. There are commercial parking ramps under buildings in downtown areas that are heated in the winter and air conditioned in the summer. It is certainly technically possible to heat and air condition a garage. Of course, in Florida, you'd only need to consider air conditioning a garage.

The one time cost of insulating the garage and installing a split air conditioner are not that important. Several thousand dollars, one time, no big deal. The most important factor is the ongoing cost to operate the split air conditioner to cool down the garage. I assume that it isn't cheap to air condition a garage. If you have a pool, it's not that cheap to heat a pool all winter, but obviously people spend money on heating a pool, even if its hundreds of dollars every month.

I think if you spend several thousand dollars a year to do things like heating your pool or air conditioning your garage to improve your life is worth it. I don't like spending thousands of dollars on taxes, because probably at least half the money is wasted on stupid projects and giving "free stuff" to freeloaders.

[Tom52]

I know several people here who have mini splits in their garages. They claim the the electric bill only increased $15 to $20 per month to operate. They have high efficiency around 18 to 20 seer. They keep garage temp set around 76 to 78 degrees same as inside the house. Claim is that there is no problem maintaining temp even during this summer heat/ humidity. Of course attic and doors have the required insulation.

I will be adding a mini split to my 3 car garage later this year. I will go with a 24,000 btu unit.

[davephan]

I know several people here who have mini splits in their garages. They claim the the electric bill only increased $15 to $20 per month to operate. They have high efficiency around 18 to 20 seer. They keep garage temp set around 76 to 78 degrees same as inside the house. Claim is that there is no problem maintaining temp even during this summer heat/ humidity. Of course attic and doors have the required insulation.

I will be adding a mini split to my 3 car garage later this year. I will go with a 24,000 btu unit.

Thanks for the post! Only about $20 a month is dirt cheap to air condition the garage. I was guessing it might be over $100 a month.