Portable A/C in Dallas garage

[22lover]

garage sqft = 525
assume garage door, ceiling, and 2 walls insulated decently
remaining outward (SE facing) wall is marginally insulated
Have garage fridge that produces unknown heat

Want A/C to make it pleasant to work in garage in Dallas heat. Looking at portable units only at this point. I don't want to hang meat, just not sweat profusely. Looking for a 300D or SD to restore so am looking at spending a good amount of time out there. Don't need 68F or even 75F. 80F (or less of course) is fine on a 95F day.

Several online coupon "deals" out there right now:

Soleus 8K BTU for $200 shipped (1 yr warranty)
Soleus 10K BTU for $237 shipped (1 yr warranty)
Soleus 12K BTU for $311 shipped (1 yr warranty)
Amana 12K BTU REFURB (also includes heat) for $237 shipped - 30 day warranty

What say you?

 

[Falcon67]

All I can tell you is that we've used a couple of 12K portables in our data center as a band-aid during the main AC unit repair or outage. From my experience, I wouldn't spend a $1 on one. BUT - I don't know what brand those were or how old they might be as they are stored in a warehouse where I don't have access. I was remarkably unimpressed with their output. You'd need closer to 15K BTU anyway for that space. I have a new Energy Star rated 6500 in my 12x24 work room of the new shop. With a fan, it is able to get the place to around mid 80s. Not what I expected for 288 sq/ft that's fully insulated with small double pane windows.

 

[sirsloop]

I run 2 12k window units in my garage. I have not insulated the doors yet, but they can maintain 72F in the room on a humid 90F day. I bet that could drop into the 60's with the doors insulated.

The nice thing about having 2 units with extra capacity, is you can quickly drop down the temps when you want to work, then turn one off and use the single 12k to let it ride if you choose. When I had one 12k unit in there it would remain very hot for a few hours. Heck if you opened the door and pulled a hot car in the garage for an oil change, that would totally wipe out the room for at least an hour. With 24k you can recool the room rapidly and take the heat outta the car so you are not sweating bullets.

Just my .02. More is better in this situation.

 

[wb2vsj]

All I can tell you is that we've used a couple of 12K portables in our data center as a band-aid during the main AC unit repair or outage. From my experience, I wouldn't spend a $1 on one. ...

I totally agree there. We do the same thing, our racks of Data servers crank out TONS of heat. Feels like Arizona when we vent the hot air out into the hallways. Those portables seem to be about half as effective as as good wall/window unit. I have a 222K BTU in my two car garage window. The family hates going in there when I have it on. Too cold they say. Just right I say.


So - get as big of a portable as you can afford.

 

[POS Racing]

Where are you finding these prices? Link Please!

I'd like to put one of these in my little 2 car garage. I just finished a clutch on my Daughters Miata last week and would have killed for some cool air!

How do you plan to vent it??

My garage is all brick with no windows so I guess I'd have to vent out the roof.

 

[antinym]

I have an older 10k window unit and a new 8k (sams club special) window unit in my 2 car garage The older one works better (colder and quiter). Importantly, I wouldn't suggest having less than 18k available. In the florida heat I can keep my garage at 72. I've had it down to 66 on cooler days. I really work up a sweat in the garage and I find that 68 is the sweet point for me. I generally keep the house at 75.

 

[22lover]

POS Racing - pricing is from newegg.com - sale is through tomorrow on those units. They have a 15% coupon code listed which is what brings the price down to what I wrote. Just do a search on portable air conditioners on their site and you'll get a ton of results.

WB2VSJ (ham call?) - I consulted with my neighbor who is, among other things, an A/C commercial contractor. His advice was same as yours, with the addition that I should bite the masonry cutting bullet and consider a through-the-wall (window) unit mounted near floor level OR a split system. He has discouraged me, based on his own experience, from considering the single-hose portables. Back to the drawing board!

 

[sirsloop]

A ~24Kbtu single zone split system with 1-2 blowers would be the absolute hot setup... but... its not as cheap as finding a couple 2yr old window 12k's on craigslist for $100 each. If you have a brick or block wall, drilling a little hole for AC lines seems a whole lot easier than cutting a gigantic hole for a window unit. You'd probably be pulling a ~25A 208/230V line off your panel for a 24k split, so there is some electrical work needed too.

The indoor mobile units for lack of another word BLOW

 

[Falcon67]

I'll add that I seem to see that the older units do cool better and move more air that the new fangled energy rated jobs. I will eventually end up with two - one in the 12x24 work area and one for the 24x28 shop. But I'm looking for an older 12~15K unit I can put through the wall for the larger area. I had one and tossed it 2 years ago because it was taking up space - oops.

 

[22lover]

Yes appears that there's no free lunch here. The portable units, by most online reviews and the real-world experience given here and elsewhere points to a disappointing setup. Split systems are quite pricey (at least for my budget)... window units seem to be the most economical and sure way to get things done but if you have no windows like me it becomes a more involved install!

 

[VHF]

Keep in mind also the single-hose portable units are constatantly pulling air out of the room... which means more hot humid air pulled in from outside (through cracks, etc.) which then needs to be air conditioned.

There are two-hose portable units which don't rob air from your conditioned space. No idea if they work any better in actual practice.

I don't like the roll-around portable units because they all seem to be so noisy... but I might put up with it if the alternative was working in a humid 95F space!

 

[jtbinvalrico]

More info for your research: I use a 5yr old 12k window unit that I put up high through a cinder block wall here in Tampa. Cools my two-car in 20 minutes, coasts at 76 degrees. Garage door is insulated.

 

[sxk122]

POS, I'm not sure those are TCB approved......

 

[Falcon67]

>if you have no windows like me it becomes a more involved install!
Yes - but if you buy a model with a removable chassis, it gets MUCHO easier.

 

[71flh]

Are the walls and ceiling insulated? That's step one and will make a huge difference. Do you have an attic access ladder thing in the garage? Make some weird insulating thing above it.

Often in the garage an older house has no wall or ceiling insulation. You can blow in insulation above and it will make a huge difference. If you don't mind a bit of work, you can do this cheap.

Same thing for the walls, but more difficult depending on the finish...

Is the attic vented in the soffits and ridge?

Adding AC means you have to exhaust hot air (that is make a hole).

 

[22lover]

71flh, from my original post:

assume garage door, ceiling, and 2 walls insulated decently
remaining outward (SE facing) wall is marginally insulated
Have garage fridge that produces unknown heat

The ceiling is not insulated now, but I will be doing this over the next few days. Have several extra bags of blow-in cellulose from adding to the attic a couple years ago. I will be trying to figure out how to get more insulation in the SE wall as well. Garage door is in process right now...seems like R5 'ish is about all that can be reasonably achieved there.

Affirmative on both ridge and soffit vents....

 

[pipsters]

What about a ductless mini-split, not cheap but lots cheaper than a typical split system. How long do you plan to remain the the house?

 

[22lover]

Yes that would be the perfect solution if it was in my budget. The hardware for a 12K BTU mini split is around $1500 depending on brand, must DIY a small concrete pad, and roughly $300-500 for the testing/charging that must be done after I install it DIY. I love the fact that only a small hole needs to be made in the wall and my understanding is that the mini splits are much quieter than the other options.

Unfortunately it's just not in the budget this summer - and at the same time I need (OK, want) to play/work in the garage in the coming 3-4 months with my son and not lose out on the summer time. The heat is intolerable except at night, when instead the mosquitoes decide to attack (door open).

I don't have plans to move anytime soon despite some mistakes made in the selection of the house years ago.... Oh the things learned! 1) Don't buy in this area of Dallas County unless you like your house to move on the river of clay soil underneath it. Might as well erect a sail on the roof 2) Don't choose the lowest house on the street 3) Study the C&R's carefully. Oh well, it's a great neighborhood for my son and that's what matters.

 

[sirsloop]

Get one of those propane powered skeeter killer things!!

 

[happy2rv]

You might try watching Craig's List for a used conventional split system. They are often pulled in working condition and sold cheep for various reasons. If you watch close, you can get them for a couple of hundred plus whatever it costs to install them. Even buying new, depending on size, you might come out cheaper with a conventional split system.

I'm still debating whether to go with a ductless mini-split or a conventional split system in my new garage. Right now I'm out of money for garage construction and haven't seen a killer deal locally on a used system since I got to the garage finished enough to start thinking about it...

 

[22lover]

Happy2rv - Good idea, will keep an eye on craigslist. Understand your situation on budgeting for this.

I also noticed that there are some off-brand (Chinese) split systems out there that are significantly less expensive than the name brands. I'm sure you get what you pay for...but read that most of the big names simply rebadge something made in China anyway. Service would be a nightmare, I'm sure...but having an HVAC engineer living next door might come in handy. My gut says don't do it...but came across them and thought I'd bring it up anyway in case anyone here has had any experience.

To cover all bases, I'm also back to looking at the portables - but only those with dual hose systems. There aren't many out there but the reviews on them seem to be quite favorable in general vs. the single hose types. They are also more expensive as could be predicted.

Anyway, I really want to make a decision within the next few days. I tend to spend time over-researching things and in this case it could cost me time that could be spent in my (hopefully cool) garage.

 

[Falcon67]

I've been watching craigslist too, but that's a pretty useless enterprise around these parts.

 

[22lover]

I will probably get ridden for this, but I'm going to give a dual-hose 14K BTU portable a shot. Was talking to one of my customers today who uses a small portable in his uninsulated boat house and said it did a great job. Who knows? Probably hit or miss. Buying it from a place I can return it if not satisfied. Brand is "Whynter" and the best rated I could find buying online. I figure try the least invasive economical solution first and if I have to, I can go back to the drawing board. Will be here Thursday.

In the meantime, tonight, I'm putting at least R13 above the garage (will increase as budget allows) and insulating the overhead door.

edit: Maybe I'll do R30 instead. $75 difference in materials. In for penny, in for a pound.

 

[happy2rv]

I already had a 12K Btu single hose DeLonghi Home Depot unit that I bought a couple of years ago to go in our bedroom to supplement our failing central air system in the house. It worked great in that application. It would take our ~250 sq ft bedroom from around 80 to the low 70's, no problem. So we just got the central air in the house replaced and I pulled the portable out to the garage to see what it would do. The answer nothing noticeable. I left it running all day and it was around 90 Sunday afternoon. If you are standing right in front of it, you can feel the cool air, but it just can't keep up. The garage is 26x32 with no insulation.

I'm currently leaning toward a conventional split heat pump from somewhere like ac wholesalers or whatever pops up on craig's list. If I go with a new system, I will probably install an over sized unit. I won't run it all the time and when I do I don't want to have to wait all day for it to cool down. AC Wholesalers does have ac only split systems for around $1100 for a 2 ton or $1350 for a 3 ton Goodman with free shipping. (I'm not affiliated and you might find cheaper prices shopping around. Just a quick reference point). You would have to add line sets, installation, and whatever supplies are needed for installation. But this would perform much better than any portable unit.

If you do go with the portable, good luck. I hope it does better than mine. The insulation will help, but I don't think it'll help that much.

 

[Falcon67]

No riding at all - get the thing, save the receipt and report back how it works. If it works well enough, I'd be up for one to get away from sawing a hole in the side of the shop. We'll very much appreciate the time you take to report on it's operation.

 

[flyingw]

I just bought a 12k BTU for the garage. My garage is partially insulated with insulated doors. During the heat of the day, there is more heat creeping in than it can cool but in the evening it works fine. I am also going to use it when I go 3wheeler riding. I have an ARE shell on my truck and I sleep in it so when its hot, the portable AC will cool it off inside in short order. All I need to do is to make a shroud to go over the output vent and pipe it in to the side window of the shell. Crude but it should work great for that.

 

[mike_s]

I'm glad I found this thread.

I'd considered getting the portable units for my garage because I could move them into the house in case of an outage, etc. I think they won't do what I want now.

I've got an 8,000 btu in the shop portion. Room is 14' x 12'. It cools is nicely, but the ceiling isn't insulated and gets LOTS of heat off the attic that heats up the room. it's got 1/4" crapboard on the ceiling with lots of leaks (by last owner).

If we were going to stay here, I'd tear it all down, insulate and start over. but the house is for sale. so I'll let the next owner decide.

 

[37ford4dr]

interesting thread....i have finally succumbed after complaining about the DC heat/humidity to put AC in my 500 sq ft incredibly well insulated 2x6 garage...the windows i have in the garage are 3 units ganged together but they are individually very small only about 18" opening. i went to HD and only there smallest 5k unit rated for 150 sq ft will fit in the window. i will put this unit in tonight and see what it does. this was a $99 unit so if i had to add another one i would still have some beverage money left over. luckily at night time our temps drop down and i really just need the humidity level to drop and i will be turning it on well in advance of the time i plan to be out there. this will be interesting to see what it does. i only need high 70s/low 80s* and lower humidity to be comfortable in the garage.

 

[Falcon67]

I have a new 6500 BTU unit from Lowes ($159 on sale). It's a nice E Star unit, works OK if you put a fan in front of it to circulate the air. It blows very little - maybe 5~6 feet out from the grills. It's in the long end of the 12x24 work room. Makes me want to spin the room layout around LOL.

 

[mike_s]

interesting thread....i have finally succumbed after complaining about the DC heat/humidity to put AC in my 500 sq ft incredibly well insulated 2x6 garage...the windows i have in the garage are 3 units ganged together but they are individually very small only about 18" opening. i went to HD and only there smallest 5k unit rated for 150 sq ft will fit in the window. i will put this unit in tonight and see what it does. this was a $99 unit .

Have you considered cutting a hole in the "far wall' and framing in around it so support a 10k to 24k btu unit?

I've got an 8,000 btu window unit in my somewhat insulated (but not well insulated) 12x14 shop. It will cool it down, but takes some time.

remember everything in your room/garage if it hasn't been cooled, is up at the higher temp and will radiate heat. So if I go into my garage shop and it's 90f, then all my walls, tool stands, stuff are all 90f also and it takes a while to cool down all that stuff to new temp also.

cooling is not just about cooling the air, but the the walls and stuff in the room also as it's thermodynamic makeup, they put off heat also it a rooms air.

 

[22lover]

Mike makes great points. Think about all of the heavy tools you may own. In my case, I have a quite old, quite heavy, solid iron drill press. Also a heavy welder, steel benches, steel chairs, and a couple hundred pounds (at least) of wrenches, sockets, tool boxes, and other solid steel heat sinks. I also have a gas water heater, although partitioned into a closet and well-insulated...but sure to have some effect. Also a garage fridge, which spits out more BTU in heat than it cools internally, of course. It all adds up in a hurry and that's just all I can think off at the top of my head.

Still not done insulating so will provide pre-insulation garage temp vs. outdoor, post-insulation garage temp vs. outdoor, and air-conditioned/insulated garage temp vs. outdoor. I will have the dubious fortune of having a scorching 100F weekend here in Dallas so can't get any more real-world than that.

 

[mike_s]

installing a temp/thermostat activated exhaust fan in your attic will help a LOT also.
reducing the delta/difference of heat temp between your inside space (house or garage) and your hot attic, will greatly help in your cooling and cooling efficiency.

If it's 90f-100f outside, your attic could easily be 130f or hotter. Today here our temp is supposed to be 93f.

I put in two mushroom fans that are temp activated. I think I have them set to come on at 115f, which I think they run till it's down to 105f or something like that. Remember that you install these in almost the peak of your attic so it's a lot hotter 10 feet up also.

So reducing my attic temp from 130f down to say 105f, it means that I've got a lot less heat touching the other side of my insulation. Which means there is less heat transfer into the main living space or garage space. Which means your AC unit has to work less, and doesn't have to push air through duct work that is 50f hotter than the air it's pushing, increasing cooling efficiency.

All in all, it will reduce your power bills. It's much cheaper to run a 110v attic fan, than it is to run the 220v 30amp AC compressor, plus a 110v HVAC air mover fan.


I put in new ones about 6 years ago when I replace my roof. The old ones were broken..... They've been working great since. I can tell a NOTICEABLE difference when I have to go in the attic to get something.

One last note, if you install these, install them on a wall/light switch. (you can put the light switch in the attic, etc.). The reason is, eventually a bearing will go out in the fan and it'll start making noise. It might take 10 years, but it will go out. Or it will lock up, which might cause motor overheat and fire hazard.

Having the switch will allow you to cut power to the fans until you can get up there and fix it. (which might take a few days to go get a replacement, or get a contractor out ,etc).

 

[Falcon67]

FWIW - today it's 96 on the back porch. The shop is covered with gray 3 tab and TechShield reflective decking. No insulation in the big area. The OSB ceiling is 91F, the ridge board is 111F and the underside of the decking is 105F. The insulated work room ceiling is 85F and all the walls are the same - no AC running. Thats from a whole day in the sun, no air. Once I get insulation in there, temp control will be reasonable anyway.

 

[22lover]

Great stuff Mike and Chris...

Mike - do you think the attic fans would be effective even though I already have radiant barrier foil on the underside of the roof (i.e., the attic ceiling)? I guess I need to take a reading up there but the temp reduction was definitely noticeable after I stapled that stuff (and almost collapsed of heat exhaustion) to the rafters.

I think I may invest in one of the Harbor Freight non-contact infrared thermometers to see how things are as I go...

-Bill

 

[mike_s]

Great stuff Mike and Chris...

Mike - do you think the attic fans would be effective even though I already have radiant barrier foil on the underside of the roof (i.e., the attic ceiling)?

In my opinion yes... the fans will still help some.

If I wrap a turkey in heat reflective aluminum foil and put it in an oven, it's still gonna cook.

I think I may invest in one of the Harbor Freight non-contact infrared thermometers to see how things are as I go...

I've been wanting one of those also. saw one on sale recently for $25. can't remember exactly where.....

 

[22lover]

I've been wanting one of those also. saw one on sale recently for $25. can't remember exactly where.....

Harbor Freight. You can pull a 20% coupon online anytime you want. They have two models which from what I can tell only differ in that one has a pistol grip and the other doesn't. The non-pistol grip is $20 list. The other is $40 I think. Add your coupon and off to the races. No idea if they're any good, mind you, but not a huge risk in any case.

 

[mike_s]

Harbor Freight. You can pull a 20% coupon online anytime you want. They have two models which from what I can tell only differ in that one has a pistol grip and the other doesn't. The non-pistol grip is $20 list. The other is $40 I think. Add your coupon and off to the races. No idea if they're any good, mind you, but not a huge risk in any case.

I looked at those..... the $20 one doesn't have flattering reviews. The pistol grip one does.

I think the other major difference is the temp it goes up to. One only went to something like 250f. the other to 500f +

for household the first should be find unless you need to determine engine temps.

 

[pseudorealityx]

Great stuff Mike and Chris...

Mike - do you think the attic fans would be effective even though I already have radiant barrier foil on the underside of the roof (i.e., the attic ceiling)? I guess I need to take a reading up there but the temp reduction was definitely noticeable after I stapled that stuff (and almost collapsed of heat exhaustion) to the rafters.

I think I may invest in one of the Harbor Freight non-contact infrared thermometers to see how things are as I go...

-Bill

Yes on both. The attic fans controlled via t-stat will only help.

The HF IR thermometers are neat, and cheap enough to be disposable. Also a good way to diagnose an A/C that's not working correctly. Discharge air should typically be in the mid 50's.

 

[Falcon67]

I have the pistol grip one - use it on the race cars and most everything else. Works good for me. Seems accurate to less than 3 degrees F, which is about as good as you'll get anyway IMHO. Even thermocouples run tolerances like that.

 

[mike_s]

I've put these on my previous house. (see below). current house has two that are a little smaller and square. (not sure in difference in CFM of air movement).

Searching Lowes or Home Depot web page will give you many other choices.


Like I said in an earlier post, I recommend wiring them on a switch. that way if there is an issue you can easily cut power to them.