Getting/keeping the heat out

[palsor1]

Hey guys,

I live in Austin, TX where it routinely gets over 100 degrees in the summer and my attached garage gets HOT. This isn’t helped by my house facing west so the afternoon sun beats down on the garage doors and heats everything up. You can see a picture of my garage below. The two bays to the right are below living space, and the by to the left is below attic space. There are no windows or other ventilation and insulation is limited to the walls shared with living space. I’m looking for advice on what would actually help.

Here are some ideas I have considered:

1. Insulate garage doors - Ideally insulating the garage doors would keep the heat from the afternoon sun out. Of course, this would keep the heat from the cars in, so ultimately I’m not very clear whether this would be a benefit or not.
2. Add a window - I could have a contractor put a window in the side of the garage. The hope is that I could open it on hot days and get some cooler air moving though. This would also help let in some light while the garage doors are closed. The down side to this is that the left side of the house is brick and is where all of the electrical and AC lines run into the house so we’d have to cut through the brick, put a window in, and rebrick all while avoiding existing stuff in the walls.
3. Build a vent into the attic - The attic already has vents in the soffits and hawk vents in the roof to let air move through there. My theory here is that I could vent up into the attic space and the hot air from the garage would make its way up there and out the hawk vents in the roof. I have no idea how big of a vent I would need to make this useful.
4. Build a vent up to the roof - In the previous bullet I was suggesting venting into the attic. Here I’m suggesting venting all the way up to the roof. I don’t know enough about air flow to know whether this would be better or not.
5. Put a fan in the ceiling to vent to attic/roof - A variation on the previous two option. Instead of just putting a passive vent in, I could put in a fan to actively pull air from the garage and push it into the attic or out of a roof vent.
6. Insulate the attic and left wall - similar to insulating the garage doors, the hope is that this would keep some heat out, but this would also keep heat from cars in, and I don’t think has as much obvious benefit because the attic and left side of the garage are pretty well shaded on the outside so i don’t think the sun hits them as hard.
7. Add a mini-split AC - This would be ideal, but for some reason this doesn’t seem efficient to me yet. I think I need to find more passive ways to get temperature under control first.

Obviously cost is somewhat of a concern, but I’d really like to understand what everyone thinks would be effective first. If you guys have any thoughts, please let me know.

- Andy

 

[bobbyjean]

what temp would you be looking to maintain,sure a vent fan to attic alone works...it could be set to run off a temp control...
access above the two bay is out ...there should already be insulation there...
are the double and single bays open to each other?
if so a ductless works , if not a traditional split system may work...need to eat some space up for that though...heat pump either way

 

[PoorOwner]

Can’t tell from picture but look like single layer steel door from builder. I would replace them. The house would look better too.

Just save up to get an air conditioner. You won’t have to worry about the other things you proposed, they would take hours to make a one degree difference but ac will get your temp down 10 degrees in an hour.

 

[talonboy]

Insulate the doors, the kits are fairly cheap and easy to install. It will make a huge difference if your doors face West. Replacing the doors with insulated ones would be better, but much more money.

Insulate walls and ceiling if they are not now.

Install a ceiling fan, near were you work most.

I did these three things, and it made a huge difference in my garage in Las Vegas. My door also faces West.

Paint the doors a lighter color, or with a Sun reflecting coating for roofs. I used a product named Henry roof coating on the top of a storage container, and tin shed, and it made a huge difference to the inside temp of the metal surface. Am still debating doing the garage door.

 

[stm317]

Insulate the hell out of it wherever you can, and then get a mini split.
Insulation slows heat transfer, so your garage will heat up more slowly in the afternoons, and is unlikely to reach the same peak temp as a result. Conditioning the air is the next step, and that will keep heat build up to a minimum. AC will also pull humidity out of the air and make it more comfortable

 

[Black Oak]

looks like living space over 2/3 of your space. is there any uninsulated area you can improve? if so , is it vented? i would fix what i could and get a mini split. not sure a window is the answer.