Cheap Cooling Solution St. George Utah Garage

[WolfgangFox]

Hey all,

I have an 1141 sq foot garage in St. George Utah (temperature today is going to be 106) that gets dangerously hot. I don't have a thermometer in there, but I'd guess it to be about 120-130 in the heat of the day. The garage is finished but I don't think the roof is insulated at all, and the bright Utah sun is really just baking the roof. Also, it's rather large with a big RV section and 15' ceilings.

My home builder has recommended an A/C unit that works very well, but I'm just looking for more of a venting option right now, as I have no vents at all in the garage.

My goal is get it to about what it is outside, but maybe feeling 10-20 degrees cooler because it's shade, and not out in the direct sun. My first idea was to install a gable vent in the back of the garage about a foot away from the roofline in the center of the RV portion (so about 13-14' above ground). Then I can either open the garage doors slightly when it's this hot outside, or for a more permanent solution install garage door vents on both sides (RV and 2 car garage side).

My thought process was the heat is radiating from the roof, and there is no vents or any way for it to "escape". So it just keeps getting hotter and hotter in there. By the time it's morning, it feels "normal", but by 12-1pm, it's a sauna in there. I was thinking of using convection properties, and have vents to draw in cooler air at a low point in the garage, then let it push out the radiated burning up air at the top of the garage through a vent.

My questions are:

How big of a gable vent would I need?
I'd rather not have a fan, but if a fan would improve it quite a bit I'd entertain the idea. Would a fan be that much more helpful?
Is this solution good enough just to bring it down from 120-130 to about 90-100 in there? I can hardly stay in the garage for more than 5 minutes without coming side the house absolutely sopping wet. And this is with about 25% humidity today. It's a desert environment, so I wouldn't think outside humidity would be a factor, just man made humidity from the inside of the house.

Pics are following.

This is the 2 car garage side. I was thinking of installing vents on the door itself or leaving it open maybe a foot or so for circulation with the Gable Vent on the other side.

This is a picture of the RV garage side. It's a tall ceiling, but I'd install vents here at the bottom of this door as well?

In the pink highlighted area, on the RV garage side was where I was thinking of putting the gable vent.

I have a regular entry door on the side of the RV garage also, didn't know if I could add or do something with this? I was thinking of maybe putting a security screen door on the outside and leave it open when I'm in there for additional circulation.

You can see the attic here extending over the 2 car garage side. There are gable vents for the attic to vent.

This is a gable vent for the attic.

In the pictures you can see I have some windows as well. These are just for allowing light in, they do not open up.
I apologize for the mess. I restore arcade games and pinball machines, and I can tolerate an hour in a warm/hot garage to work on these. But it's just so hot in there now, it is literally unbearable and borderline dangerous if you stay in there too long. I haven't been able to get it cleaned/organized yet as we just moved in last year.

I'm interested in your input! If there are any additional measurements that would help find a solution, or anything I've forgotten, please let me know. I just want to get out there and work an hour or two a day if I could.

-Pat

 

[b-boy]

Personally, I think I'd insulate the ceiling and install some ceiling fans.

That way if you do decide to use A/C, you're already insulated.

I have a 30x40 pole barn. Last Summer I was barely to work out there. It's fully insulated now and has 2 ceiling fans. It's very comfortable, even when it's in the mid-80s outside.

 

[gayler]

Put in as much insulation as you can!

 

[BoostAddiction]

Yeah, sealing (first) then add as much insulation as you can afford. If you actually work in there, the insulation will make a huge difference. Ceiling first, then the walls.

Then get a minisplit. They are the perfect solution for the garagista. Better ones are very inexpensive to operate, and you only need to run them when you are out there. Works in summer and winter, too.

Vents are going to largely be ineffective if you really want to work there- don't waste your time and money.

 

[SGKent]

You can add some kind of louvered fan and vents. That will allow air flow and make it ambient temps. My garage here in the Sacto area is insulated and dry walled. It was 105F outside yesterday and about 95F in the garage. If I cool it down at night by running fans into it, it stays cooler all day but I have to get the temp down at night or that doesn't work. The cost of electrical power makes it too expensive to actually AC it.

 

[WolfgangFox]

Thank you all for the comments.

Amazingly enough, my home builder came over today to do some warranty work. There is no insulation "above" the ceiling and below the roofline in the RV portion of the garage. I'd assume there is some above the 2 car, but not sure.

When you talk about ceiling fans, are you just referring to normal indoor ceiling fans, you put in your living room, etc?

And the general consensus is no gable vent, but just the insulation and ceiling fans?

 

[pbon]

An attic type fan, maybe with louvers in the ceiling ducted to your gable vent would cool it down fast. Could put it on a temperature switch or timer. Then use several ceiling fans.

 

[acmikee]

and exhaust fan on you gable end will only vent the air out of the attic which will help if there is an opening on the other end to cross ventilate the space.
your idea of adding a security door with a fan will only cool it to the outside air or even a portable evap cooler and can be done this weekend
adding a ductless split wont happen over night or even in a few weeks. im sure all of the ac companies are busy

 

[Jon In Tucson]

your idea of adding a security door with a fan will only cool it to the outside air or even a portable evap cooler and can be done this weekend.

Second on the evap cooler. With 25% humidity it will work fine and potenially knock 20* off the ambient. Most of the big box stores will have the portable models. This help you out till you make a decision on a long term solution.
Jon in Tucson

Sent from my SM-G930V using Tapatalk

 

[WolfgangFox]

I got a thermometer over the weekend, and it's reading about 1-4 degrees warmer inside the garage, than it is outside. When nighttime approaches, it's about 5-8 degrees warmer for a little while.

So the last 2 days it was about 98-99 degrees outside, inside the garage it would read 100-102. So I guess my original declaration of the temperature was exaggerated. However it really feels quite stuffy in there. I'm sure it's because of the lack of ventilation.

Thinking out loud, it sounds like from the cheapest to the most expensive would be:
Gable Vent and leave garage doors open a touch.
Gable Vent with ceiling fans.
Evap Cooler.
Gable Vent, ceiling fans, and exhaust fan.
Add insulation, Gable Vent.
Add insulation, Gable Vent with ceiling fans.
Add an A/C type of system in there.

The least invasive would be to add insulation. If I get ceiling fans that hang down too low, it would remove some of the clearance needed for an RV to park in there when I sell the house.

On the model home, the home builder has a mini split Mitsubishi model, and he has his office out in the garage. It's the only thing cooling down the garage, and it's the same setup, otherwise as mine, and it's a nice mid 70s in there even with it being hot outside.

This also, isn't our "forever" home. We're just planning on staying here about 5 years or so. I'm 99% sure the next person who buys it is just going to use it as an RV garage. So I feel like the more money / work I put into this, the next owner will probably not appreciate it if he's just parking an RV in there.

I'm really leaning towards the insulation, Gable vent, and ceiling fan combo, and starting with insulation first, then adding vents fans if necessary. The hot months are June, July and August. Otherwise, I just stay out in the garage for an hour or so, and even at mid 80s to 90 degrees outside, inside the garage really isn't horrible since it's in the shade and the humidity is so low.

Two more questions I had:

The RV garage side is over 55 feet long. Would it be beneficial to add 2 gable vents, one on the north side of the garage, and one also on the south side where the garage doors are?

In the winter months last year, it did get below freezing a few nights. It never went below 37 as the high (usually around 45-60), but the lows during the night did get down to 10-12 degrees. With the gable vent added, but the fans off and garage door closed, will it make the garage get much colder, or will it lose a lot of the heat during the day? I seem to remember it wasn't terribly bad working in the garage during winter at all, and I didn't want to make it too cold in the winter, with the ventilation system.

 

[dagofast]

We're in Phoenix and experience similar temperatures. Our RV garage is 20'x50', stick built with 2"x 6" walls, a radiant barrier on the underside of the roof decking and heavily insulated in the walls and ceiling. It is a separate structure from our uninsulated 2 car garage. In the winters, the 2 car garage can get quite chilly, like high 40's-to low 50's. The insulated RV garage never goes under 63 degrees. It has HVAC but I've never needed to run the heat. In the summers, the 2 car garage gets unbearably hot just like yours. The insulated RV garage would eventually get pretty hot too, but after the first summer of trying to just switch on the AC on the days I would be working out there, I now keep the AC on but set to about 84-85 degrees.

We found that trying to cool the building (and contents) by switching the system on after everything has become heat soaked means the AC unit will run solid for the entire day. And you still won't get the building comfortably cool, it would stall out at about 85-86 degrees, especially as the heat continues to build during the day. Now when I know I'll be working out there, I take the thermostat off "hold" and let it revert to the program which will start cooling the building down to 80* about 5AM and then maintaining it. When I'm done, I'll raise the temp and put it back on hold.

 

[SGKent]

add insulation first. That will not stop the heat - it delays the heat. Instead of showing up at 2pm it will show up at 3am. Then add a whole house fan and run it at night once the temp outside cools enough. Here in Sacramento it has been in the 100's this week. If the whole house fan is run at night the AC doesn't come on until 2pm or 3pm instead of 9am. The garage is cool in the morning. I have a well insulated garage but it still gets warm because insulation only slows heat transfer. It doesn't stop it.