OK Guys! Old Gal needs help again. I've been reading threads for weeks and still don't know what to do about my new house build in an AZ HOA. I'm meeting with designers on Wednesday and need to have my mind made up on the garage. I wanted a cooler garage for storage and occasional stained glass/jewelry torching workspace (can possibly be done in house instead). I am not going to DIY so will have to pay top dollars to professionals. Here are the specs I know: Attached garage faces west - back wall of garage attaches to house. Approx sq. ft. is 460 - 550. House is stucco with tile roof. Standard garage insulation is R-22 but I can pay $3200 for upgrade to R-38. Garage door is insulated (First United Door - Steelite Delano). I can add a GF-14 garage fan and attic cooler and have been rough-quoted $3500 for 18,000BTU minisplit. Questions: Is this crazy to try to cool AZ garage? About how much would my APS bills increase just to cool the garage in the summer (only to 80 or so) with a minisplit? Who's done it?
Hot Arizona Garages
- Thread starter ctiff66
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cspcrx
Well-known member
Im in the same boat, exept mine is already built. Many others have successfully cooled theirs. My plan is a mini split. Mine is fully insulated and after two cars park in it its 102 in there every morning. Good luck.
shade
Well-known member
I did blown in cellulose all walls and in the ceiling above. the ceiling above is a bedroom ($750)
garage door is also insulated
i went with an 18k through the wall and it cools a 3 car tandem at 700sq ft to 77 degrees when i set the unit to 77 degrees.($500)
cost to run the unit maybe an extra $20 a month
Bring on the 115 degree heat - Gilbert, AZ here
garage door is also insulated
i went with an 18k through the wall and it cools a 3 car tandem at 700sq ft to 77 degrees when i set the unit to 77 degrees.($500)
cost to run the unit maybe an extra $20 a month
Bring on the 115 degree heat - Gilbert, AZ here
papavolume
Well-known member
Subscribing for suggestions! I just try to only work in my Phoenix garage at nights in the summer but that is a less than ideal solution when there is a ton of stuff to get done.
The fan I plug in at times just isn't cutting it either!
The fan I plug in at times just isn't cutting it either!
j p smith
Well-known member
NOT CRAZY. But lets think about this a minute, you are not going to live in there. I would consider doing the insulated door, standard insulation, if that includes the attic and 3 walls. AC, look at what shade did with the thru the wall unit. Today these units are fairly efficent, good compromise, not sure they are in the 500 dollar range if you are paying an installer. You will also need an electrical outlet for the unit.
I am not familar with the GF-14 garage fan attic cooler
Using a torch in there is going to affect the cooling also and any time the door goes up you are going to lose cool air.
I am not familar with the GF-14 garage fan attic cooler
Using a torch in there is going to affect the cooling also and any time the door goes up you are going to lose cool air.
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theoldwizard1
Well-known member
You pat for insulation once, yo pay for heating and/or cooling every time your HVAC system come on ! Buy all the insulation you can possibly afford !
That looks kind of gimmicky. Why nor just install a whole house attic fan with some big gable vets or roof vets,
Your only "crazy" if you buy it and don't use it ! Insulate, insulate, insulate ! Is there some kind of premium roofing decking you can upgrade to that will add additional R-value or better reflection ?
You need to shop around. I'll bet you can find solar powered attic fans !
cspcrx
Well-known member
Problem is the insulation does a great job of turning the garage into a hot box. Mine is fully insulated, all walls, doors and attic above it. Once the cars get pulled in it traps the heat in. I think a ductless is the best way to go. Just getting one installed and not getting taken in the process is the trick! I was quoted $6000 for a 24000 btu mini split installed. That is just way to much!
James-W
Well-known member
I have R-19 in the walls and R-30 in the ceiling. I am running a window air-conditioner and it works well. But I am in Wisconsin and we don't usually get the heat that you do in Arizona. Still, with a well insulated garage I would think an 18,000 BTU window unit would keep the garage pretty cool.
justinjoyal
Well-known member
Falcon67
Well-known member
Minis are pretty efficient and with the garage insulated and air sealed walls (like the house) the mini should not have much trouble keeping the place usable without busting the power budget. Plan some desert type landscaping like maybe Oleander bushes on the west side to kill some of the heat. Light colored paint helps - the HardiPanel on the outside west wall of my shop runs 130F in summer painted gray. When it was Barn Red, it was 180F. Have a couple of trees on that side but they are slow growers. I tried some "grow anywhere no care" Crepe Myrtle bushes and the heat killed them.
sanatarium
Well-known member
In AZ too here. Recently overhauled my garage, R-38 roof(plus 1" polyiso foam roof with white reflective elastomeric coating) and R-18 walls, sealed up nice and tight. Recently insulated the garage door too with some polystyrene panels, estimated about R-5 for the whole assembly.
I have a 10k wall A/C that I leave set to 90 when I'm not around, just to maintain the thermal state of the garage, so that when I want to work, I set the target temperature to 80 and it hits that in about an hour. I have worked for up to 6 hours with it at 80 degrees and the A/C runs very infrequently. Maybe 15-20 min per hour. No data on electric bill yet.
From my experience, maintaining temperatures or lowering the temperature by a small amount is easy. Trying to take a garage from 105 down to 80 is a monumental task. You have to consider the 'thermal mass' of the building and its contents. If you allow all the contents, metal tools, toolboxes, flooring materials, workbenches, to reach 105 degrees, which they would in a steady state when the room is 105 for several hours, those items take far longer to cool than the air in the room. They hold heat and continue to radiate heat for several hours, and the A/C has to work to overcome that. I am estimating it will cost a few dollars a month to maintain my garage at 90 instead of 105, and when I want it at 80, it's an easy task for the 'little A/C that could.'
Also agree with Chris, light colors are best, and use landscaping to your advantage. I have planted trees to strategically shade my garage and house in the summer yet be out of the way in the winter so the sun can help warm the building.
I have a 10k wall A/C that I leave set to 90 when I'm not around, just to maintain the thermal state of the garage, so that when I want to work, I set the target temperature to 80 and it hits that in about an hour. I have worked for up to 6 hours with it at 80 degrees and the A/C runs very infrequently. Maybe 15-20 min per hour. No data on electric bill yet.
From my experience, maintaining temperatures or lowering the temperature by a small amount is easy. Trying to take a garage from 105 down to 80 is a monumental task. You have to consider the 'thermal mass' of the building and its contents. If you allow all the contents, metal tools, toolboxes, flooring materials, workbenches, to reach 105 degrees, which they would in a steady state when the room is 105 for several hours, those items take far longer to cool than the air in the room. They hold heat and continue to radiate heat for several hours, and the A/C has to work to overcome that. I am estimating it will cost a few dollars a month to maintain my garage at 90 instead of 105, and when I want it at 80, it's an easy task for the 'little A/C that could.'
Also agree with Chris, light colors are best, and use landscaping to your advantage. I have planted trees to strategically shade my garage and house in the summer yet be out of the way in the winter so the sun can help warm the building.
cspcrx
Well-known member
You bring up a good poimt that i had not thought of. My thinking was to just run it when i would be in there working. However, you bring up a good point of how much will it take to get everything cooled down from 105 degrees?
The the only issue i see for me is if i kept it set at, lets say 90 degrees, and each night pull two balzing hot cars in how much energy will that take to cool it down every night verse the other option above.
I dont have this answer and i also guess the frequency at which you will be in there would have to be considered.
The the only issue i see for me is if i kept it set at, lets say 90 degrees, and each night pull two balzing hot cars in how much energy will that take to cool it down every night verse the other option above.
I dont have this answer and i also guess the frequency at which you will be in there would have to be considered.
rsanter
Well-known member
How much room do you really need for what you are going to do?
What if you framed in about 1/4th of the garage in a corner up against the shared wall to the house. You will still have room to park one car and the other fourth for storage.
Then a simple through the wall unit could keep that insulated room cool
Bob
What if you framed in about 1/4th of the garage in a corner up against the shared wall to the house. You will still have room to park one car and the other fourth for storage.
Then a simple through the wall unit could keep that insulated room cool
Bob
sanatarium
Well-known member
+1. This is what I do too. It's like taking a hot hunk of steel from a furnace and putting it in the freezer. All that stored energy has to flow out of the garage through the A/C in the form of heat. Best to let the car cool outside and bring it in after dark if you want to.
rattle_snake
Well-known member
I personally wouldn't go with an exhaust fan that vents to attic, to limit a fire spreading to attic.... and it look like you will be using open flame. go with thru wall exhaust fan. an attic fan is still a good idea, put it on a timer. You will also need an air intake if you want to run the fan with doors closed. upgrade to r38 price seems really high.
TangoFoxTrot
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I live in AZ and have an traditional separate ,central AC tied in the garage, the house came that way with a dedicated system. It is a nice feature, but it would cost way too much for me to leave it on all summer. I could easily see it adding a massive amount to my utility bill if I left it on through the summer months, even at like 80 degrees.
It's a tough task even with a well insulated garage if you're actually using it with hot cars coming in and out and the garage door opening and letting out the cold air and it's 110+ outside.
I would lean towards a wall or window unit and just have it near your workspace unless there's some restrictions or you don't like the cosmetics. Also, I have a relative that put a swamp cooler and I think it works much better for a garage in AZ, it can cool a space very quickly and cost pennies a day to operate. It's just not going to get ice cold but you can comfortably work in there in the summer months.
I think mini splits are a great option for a garage, but you almost have to put the system in yourself as it seems installers really want to shoot the moon on them.
My brother just got an estimate of around $6,000 when the same exact system costs around $1,200 complete. I have no problem paying a tech $100 an hour, but I don't even see how a pro could spend 8 hours doing it, much less the 48 hours he's billing. Those sort of quotes seem pretty widespread.
It's a tough task even with a well insulated garage if you're actually using it with hot cars coming in and out and the garage door opening and letting out the cold air and it's 110+ outside.
I would lean towards a wall or window unit and just have it near your workspace unless there's some restrictions or you don't like the cosmetics. Also, I have a relative that put a swamp cooler and I think it works much better for a garage in AZ, it can cool a space very quickly and cost pennies a day to operate. It's just not going to get ice cold but you can comfortably work in there in the summer months.
I think mini splits are a great option for a garage, but you almost have to put the system in yourself as it seems installers really want to shoot the moon on them.
My brother just got an estimate of around $6,000 when the same exact system costs around $1,200 complete. I have no problem paying a tech $100 an hour, but I don't even see how a pro could spend 8 hours doing it, much less the 48 hours he's billing. Those sort of quotes seem pretty widespread.
Has anyone actually used an evaporative cooler in a garage in the summer months in AZ with success? As in a decent working temperature. I haven't had much luck with my small portable evaporative cooler during the June through September period.
TangoFoxTrot
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The portable ones are not nearly as effective as something like a dedicated, mounted evaporative cooler that goes through a wall or ceiling.
If it's one of those portable ones and it's in an enclosed area and can't bring in outside dry air, it eventually becomes nothing more than a fan. I have a mobile one and it takes the edge off in some situations but it's just not the same.
In AZ we have the Monsoon season where it does get humid so during those few weeks, it's not going to do much but I think the benefits outweigh it as you can can economically cool the garage year round if you want to as Phoenix has such low humidity. It's hot here for more than just 3 months and even if it's not crazy hot outside, it's nice to have a cooler garage when you're working.
sanatarium
Well-known member
I agree on the evap-cooler subject. They are great when its dry here, but the humidity spikes around early July and they become ineffective. Also, humidity in the proximity of your precious tools that can rust isn't a good idea either.
The mini-split systems have some pretty insane EER ratings(efficiency), something around 20 I believe, which means they are very energy efficient. My wall unit is 11.8. Mini split will be cheaper to operate in the long run, but yes, the installers are REALLY proud of the work they do. I don't quite get that $6,000 figure either when the system only costs $1,200 ??????
The mini-split systems have some pretty insane EER ratings(efficiency), something around 20 I believe, which means they are very energy efficient. My wall unit is 11.8. Mini split will be cheaper to operate in the long run, but yes, the installers are REALLY proud of the work they do. I don't quite get that $6,000 figure either when the system only costs $1,200 ??????
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TangoFoxTrot
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It's almost like they don't want to do it because they're not familiar with them, so instead of turning it down they just add a huge price tag to steer you in a different direction.
My guess is with time as they become more common, the price of installs is going to come back to Earth. But even a real light DIY'er can handle the install pretty easily and then let a pro maybe connect the line, vacuum it down and flip it on for a few hundred. It's definitely worth my time to spend an Afternoon on it to save several thousands.
OzarkMan
Well-known member
I have been quoted $4100 for a 36,000 btu mini split for my 1080q ft garage. Unfortunately, the discretionary funds ran out as we need to finish the kitchen first.
That being said, I had the garage insulated to R38 in the attic (Insulation is wire tied to roof decking) and R-19 in the 2x6 walls. Right now, it is not that bad inside. Garage is loaded with furniture, tools and junk that I have been selling on Craigslist.
That being said, I had the garage insulated to R38 in the attic (Insulation is wire tied to roof decking) and R-19 in the 2x6 walls. Right now, it is not that bad inside. Garage is loaded with furniture, tools and junk that I have been selling on Craigslist.
Do you have a thermometer in the garage? If so, what is the temperature range since the heat moved in (as in the 85-90 degree temperatures in the a.m.)?
cspcrx
Well-known member
Not sure about MesaAzguy but mine is between 100 and 102 at around 6am every morning on the wall thermometer. When I turn the car on it shows 98 to 100 at the same time. So within 2 degrees of each other. When I get home in the afternoon the wall thermometer reads around 100 when the 1st car pulls in.