AC unit recommendations?

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Forum topic by Cosmicsniper posted 07-19-2011 04:33 PM 1323 views 1 time favorited 10 replies Add to Favorites Watch
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2199 posts in 2033 days

07-19-2011 04:33 PM


I will be redoing my garage shop electrical soon, and in the process I will insulate for better temperature control. Being in Texas, obviously it would have been nice to ALREADY HAVE this done (!) but, alas!!!

The nice thing is that my wife said that if she can finally park on one side of the garage then I can put in an air conditioning unit…so I’m rapid dumping everything that’s been clogging up that side of the garage bay! Granted, it’d be nice to have the WHOLE garage for myself, but I have enough things on wheels to make good use of the space regardless.

Because I lack a window, I will be looking for either a portable AC unit OR one of those that goes on the wall and is somehow piped through the wall (don’t even know what those are called). I wondered if any LJs could recommend a specific unit or advice on the entire project.

Specifically, the garage is your typical 400 ft.^2 square space with two insulated garage doors. The garage is finished with drywall, so I’ll likely tearout the upper 1 foot of drywall in order to do the rewiring and outlet drops…and in the process fill up the walls with insulation. Any recommendations on how to blow that insulation in and assure that packs in correctly?

-- jay,

10 replies so far

View wiswood2's profile


1138 posts in 2570 days

#1 posted 07-19-2011 04:48 PM

you could cut a hole in the wallm frame it out to the window unit size an d put in a window unit.make sure you have a good filter in front of the filter that is on the unit,it6 will have to be cleaned every day.mine plugs up very fast. good luck.

-- Chuck, wiswood2

View Greg..the Cajun Wood Artist's profile

Greg..the Cajun Wood Artist

5556 posts in 2183 days

#2 posted 07-19-2011 05:41 PM

This ad on your Lumberjocks page just popped up for a portable roll around A/C. Looks like what you might be looking for. I guess lumberjocks searches for words and then inserts ads they find similar.,default,sc.html?mtcpromotion=Google%20Content>Image%20Ads%20Test&utm_source=google&utm_campaign=Image%20Ads%20Test&utm_medium=Portable%20Air%20Conditioner%20160x600&utm_term=portable%20air%20conditioner&src=google&gclid=CIzK29jejaoCFQ5Y7AodHU_Uxg

-- Each step of every Wood Art project I design and build is considered my masterpieceā€¦ because I want the finished product to reflect the quality and creativeness of my work

View dbhost's profile


5386 posts in 2106 days

#3 posted 07-19-2011 06:07 PM

I am using a Royal Sovereign ARP-1400WW 13.5K BTU portable unit. My garage is a 2 door garage, and the duct work passes through the wall between the garage doors using 5” dryer vents which were NOT easy to find… I was able to locate the units via which were painted to match the siding so as to not stand out from the street. I attached the hoses to the duct with simple aluminum HVAC tape like you would seal up a metal duct to a metal duct joint. I could have run screws through the duct and end adapter of the unit, but I didn’t want to drill the plastic end adapters.

I would HIGHLY recommend that you insulate the exhaust side duct (good portable units have 2 ducts, and intake, and an exhaust, to avoid mixing intake and exhaust air, thus making the unit more efficient), this will keep the exhaust dust from becoming a radiator in your shop and just spewing heat back into the air you just cooled.

I do need to do the electrical upgrade and insulation in my shop, but I did want to mention that I have insulated my doors. Those I used 2 layers of the R-Max R5 rated 3/4” foam board insulation with the foil backing. I faced the non foil sides toward each other, so that a foil side faced out both ways. So I effectively have R10 with radiant barrier at the doors. It’s no R20, but it is about as good as you are going to get for roll up doors…

For what it’s worth, my plan is to rip the drywall all the way down, run my electrical and insulate, and then re sheet rock the garage. But then again, I have water damaged sheet rock in my garage from the previous owner (roof leak he took too long to fix).

Even without the drywall problem, I would still try to figure out a way to stand up batt insulation in the cavities as the loose fill insulation tends to settle over time and lose its effectiveness.

-- My workshop blog can be found at

View hatcreek's profile


19 posts in 1567 days

#4 posted 07-19-2011 11:45 PM

The Units you are refering to are called ductless mini splits, there are a few companies out there that have make them I have two of the Mitsubishi brands and they are worth their weight in gold. I ordered mine from a company out of Florida called A/C Wholesalers for $1300.00 each and I had them installed for around $500.00 Local a/c companies wanted around $3200.00 for one unit installed so we got a huge savings doing a little leg work on our own. These unit are heaters and a/c’s and are super efficient it the ones i purchased are 22 sear units. Please let me know if you have any questions

-- Hat Creek

View MedicKen's profile


1603 posts in 2336 days

#5 posted 07-20-2011 12:08 AM

I have a 2 car garage that I did a full reno on a few years ago. I replaced the garage door with an insulated one, it faces EAST of all directions. The drywall was all removed, new electrical was added, insulated with R13 in the walls and R30 in the ceiling. I have a door that leads to the side of the house, which is metal skinned. I cut an opening an installed a 15,000 BTU window a/c unit. It is 115V and does a real nice job of making the space comfortable. On out really hot days, our climate here is very similar to yours, 105+ I can keep the shop and a nice 80 or so degrees. If I had to do it over however, I would add a few ceiling fans to help with circulation. I found the unit on CL for $100 and it had very low mileage

-- My job is to give my kids things to discuss with their

View Cosmicsniper's profile


2199 posts in 2033 days

#6 posted 07-20-2011 01:12 AM

Thanks for the tips, folks!

Chuck: The problem with cutting a window is that it would be seen from the street and it’s a brick construction. I wouldn’t want people seeing the window unit from the street. I hear you on the filter though.

Greg: Those types are my first impulse, but I’m not sure they’d be powerful enough. With my heat, I don’t need it to be an icebox during the summer, but I don’t want the unit running more than it has to either. I figure with my space I need to target around 18,000 btu to compensate for the decreased efficiency of the room during the summer. I will try to insulate it as well as I can, but there are no guarantees in that regard. I’ll keep looking to see if there’s a portable unit out there that will really do the job…I have looked much yet.

DB: Really good information, exactly what I was looking for. Good point about the advantage of batt insulation. I just wanted to avoid stripping the entire thing to keep from having to make too big of a mess (and moving out a lot of tools and junk. There is living space above the garage (two story home), so it’s not like I have an attic to run new copper from above. I’ll need to explore ways to employ batt insulation without wrecking everything too much. My thinking was that once I remove that portion of the drywall, I’d just replace it with a strip of plywood. That would give panel access to everything should I need to do it again.

Hat: You living in Azle (my birth place), I know you sympathize with me here in Grapevine! Thanks for the terminology…I actually have been looking at the mini splits earlier in the day and am definitely intrigued. I like the idea of getting things off the floor and being able to regulate temperature in both the winter and the summer. Unless I win a lottery that I never play, this will likely be my home well into retirement age. I noticed that many people do install those units DiY. Between myself and a friend of mine, that would be a slam dunk (my construction and trades skills pale in comparison to his). I’ve seen that some units actually come precharged, so it’d be all the better if I can avoid an HVAC-guy altogether. Even so, it wouldn’t be too big a deal to have one come out and do that. I do like the idea of a bigger BTU unit though…just need to research the different options and the whole “SEER” thing.

Ken: Thanks! Your numbers perfectly parallel with my thinking on that. I was hoping for a 25 degree delta (or better) on those hot days and was thinking that 12,000 btu units would likely fall just short of that.

Wonderful stuff, guys. If you have further thoughts about insulating or experience with specific AC units, I’d very much covet the information!

-- jay,

View Cosmicsniper's profile


2199 posts in 2033 days

#7 posted 07-20-2011 01:19 AM

Oh, hey DB…I didn’t realize you were in League City! You definely have some of the same issues as me!

I was wondering…I know you haven’t done your shop refit yet, but what kind of temperature delta are you seeing with that 13.5k unit? Currently, it’s probably not all that comfortable on hot days, but certainly you can at least tolerate things, right? Right now, it’s very difficult to stay out in the garage for too long…even with a big shop fan roaring!

-- jay,

View Grandpa's profile


3239 posts in 1550 days

#8 posted 07-20-2011 01:40 AM

The mini split units work very well in our area. I am in Duncan OK and I think we are warmer than you guys in the Dallas area. We also get colder. I have seen them and operated them in homes where a large room had been added on and there was no place for ductwork. They made the room very liveable. I do understand that is not the same as a shop but it is something. In a home you need 1 ton of A/C for every 500 sq ft. Myself I am using an 8 ft door on the south and 2- 9 ft doors on the north and a fan. I am just not working out there in this 108 deg. weather.

View MedicKen's profile


1603 posts in 2336 days

#9 posted 07-20-2011 03:16 PM

For what its worth, I just looked at my AC unit and it is 12K BTU not 15 as I previously mentioned. IIRC I went with the 12K unit because it became available and was a lot cheaper than the larger unit. I am a cheap ass and did not want to fork out the big bucks.

-- My job is to give my kids things to discuss with their

View dbhost's profile


5386 posts in 2106 days

#10 posted 07-20-2011 04:08 PM


I have insulated the overhead doors and the ceiling (Doors R10 with radiant barrier, ceiling with R30) and I can typically bring the temp down from 90 deg 90% rh to 75 deg 50% rh in less than an hour. Thankfully due to the drought, I have had very low rh this year.

If you are doing insulation and electrical, you may find that a tear out / rebuild will be less hassle than trying to weasel everything in and out of standing drywall… If you insist on staying with the standing drywall, just blow it in, and expect to add some more in about 10 years…

Mind you, stupid me moved to coastal Texas after growing up in Oregon. I don’t take high heat or humidity well.. But I do like getting paychecks, and there are far fewer Birkenstocks to be seen here….

-- My workshop blog can be found at

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