A/C for the shop--Will this unit work?

[Dick in Wisconsin]

Building a 1000sf race shop in the spring. Putting Pex in the floor for heat.

I can buy a GE Thur-Wall air conditioner brand new (might be older stock) for $300. It looks like a 240v applicance. Checking the NEMA outlets listed in Wikipedia, it looks like the plug is a NEMA 6-15.

Model number is AEM 18 DQQ1. Data plate said 18,000BTU.

I'm thinking I can't go wrong with this unit for the shop. I won't run it too much ... I want to get some of the humidity out of the air and make it comfortable when its hot outside.

What do you guys think about it? Thanks!

 

[Ohmthis]

It would depend on several things. How tight a building and how well insulated? How hot and what % humidity does your area see? How tall are the ceilings? Garages aren't load calculated like houses are. I think it may be a little too small. Something in the 24,000-30,000 btu might be better suited, but this is more a guess than fact. With a good sealed and insulated garage with 10 feet ceilings it would be better than nothing, but I think it would struggle in the hottest days. Best bet, would be to have someone give you a proper load calculation on it. It would be a manual N for commercial type buildings. That would tell you what size is needed. Post up some specifics.

 

[mygarageone]

Well for the price , I would take it . Yea it might be on the small side but it will certainly give you more comfort than nothing. Just reducing the humidity helps a great deal.
To put in a split system or a larger self contained , your looking at a lot more money.

You can probably sell it for that amount if you do something else down the road.

 

[Fueler]

Tip: Try to install it away from your prevailing winds. Also think ahead and have some plastic sheeting and duct tape to seal it off in the winter. Wind goes right through it.

 

[Dick in Wisconsin]

All good points. My plan is to put it on an east wall (sun only in the morning, not hot later afternoon).

The shop will be reasonably sealed up and insulated, all the big doors will face north, only man doors facing east and west, probably a few windows to the south that will have curtains.

All I'm looking for is bring the temps on hot days down to something reasonable to work on the race car.

I think this is the ticket. Being 220/240 it should operate more efficiently than a 110volt A/C unit.

Good tip on sealing it up in the winter time. Thanks!

 

[Fueler]

I think this is the ticket. Being 220/240 it should operate more efficiently than a 110volt A/C unit. Thanks!

Nah, just means it takes more juice than 120 can provide to run the compressor. It will be fine.

Be sure to design in a proper "window" for it. You will likely have to do as I did and fab up a support for it on the outside. Don't forget to angle it down just a hair for the water to drain out, not in.

 

[PWC Repair]

I think it will work just fine for what you want. Read the installation manual before mounting. Most newer units mount level because they have slinger blades that use the condensate water to help cool the condenser coil making them much more efficient.

 

[Jagmandave]

The one I put in last year does the job in my 600 sq ft poorly sealed garage just fine, and makes a huge difference on a hot summer day - so much so that I couldn't work out there on some days without it.

Mine has the slinger blades but still requires the outside be angled down slightly - just follow the install manual.

 

[Falcon67]

If you have good insulation, it ought to do well. I can keep my big 672 sq/ft work area cool with a 10K Samsung "window" unit mounted high up in the wall. I have a partition, so the tool room has a 6500 window shaker from HD. It's a POS and won't cool the room without a fan because the blower is a wimp. The Samsung has a good fan in it, you can feel it 20' away from the unit. I also added a cheap 42ish inch ceiling fan in the big room and it really helps circulation in winter and summer. I can set the A/C to start at 4:30 or so on weekdays in the summer (high 90s to over 100 a lot) and when I get home at 5:30 it's quite nice in there.

 

[oldgoaly]

A little trick to cooling the shop and saving money! run it at night when it cooler out, and set a little cooler than you want it. one it is more efficient with lower outside temps, the lower temp setting will take out more humidity. I use a 18K cool 5000 sq feet. a vented attic. limit the door openings! if you leave the door open it lets the humidity in and you loose the drying effect in a minute.

 

[sourdough]

I use an LG 120v 15,000 BTU unit (in conjunction with the forced air furnace fan for air distribution) to cool a 2100' ranch house during OSA temps of 90*-105*.

Surely an 18,000 BTU unit can cool a 1000' insulated garage, unless the doors are opened and closed all the time. The concrete floor slab is also a good thermal mass.

 

[Falcon67]

>A little trick to cooling the shop and saving money!

Good idea - works some in some climates. Here to say that it does not work in the summer here when building envelope temps approach 140F. It "helps", but it'll still be 90F in there late afternoon. This is the other side of HardiPanel - fire resistant for sure. But it get's hotter than 2 hells with sun exposure.

 

[oldgoaly]

Another thing is read the instructions! ya I know it's hard to do....
if it is supposed to be level or at a slight angle do it! you want the condensate to pool at the condensor so the fan can pick it up sling it against the condensor make lots of racket but that water cools that coil down saving you money! do not drill a hole in it to let it out!

 

[sourdough]

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Another thing is read the instructions! ya I know it's hard to do....
if it is supposed to be level or at a slight angle do it! you want the condensate to pool at the condensor so the fan can pick it up sling it against the condensor make lots of racket but that water cools that coil down saving you money! do not drill a hole in it to let it out!

Yes, do read the instructions!

Most units come with a drain hole in the rear pan. It is there for a reason! The condenser fan condensate slinger effect is there to make the manufacturer look more efficient/green. It also wears on the somewhat flimsy construction of the condenser fan. Want to replace it in a few years?

Fact is, if the unit is not installed to drain the condensate pan at all times (about 1/2" lower at the rear of the unit), it will start growing all manner of organisms. Not pretty to look at when it gets "green". All of the pollen/weed seeds/et al being deposited on the inside condenser fins (very hard to clean well) does nothing for proper heat transfer and will contribute to the probability of flash gas in the liquid line if heat transfer gets poor, and therefore a large reduction in capacity.

Don't delude yourselves: air transfer across the condenser is from the front exterior side vents to the rear (the nice clean coil you see on the back of the unit).

As a retired HVAC mech, I PM my 15,000 BTU LG every fall and spring (it never leaves its nest and gets covered in winter). How many homeowners do the same? Most just plug it in and run it until it dies. Maybe some read the O&M manual and clean the evap filter and think all is well.

Therefore, a level condensate pan with no drain just invites corrosion and organic growth.

Sorry to disagree...

 

[volleyball]

I think an undersized unit would be best for a garage. The longer run time will allow more humidity removal which will make it comfortable without being cold.

 

[Falcon67]

I think an undersized unit would be best for a garage. The longer run time will allow more humidity removal which will make it comfortable without being cold.

Good point. It's be more fair to point out that humidity can be rare here, so smaller units seem to work better. Monday the dew point locally was -14F. RH is "really high" today because of Gulf moisture in front of a dry line, - 75%. This is all a nice change from Houston and it's 90% RH @ 95F and 75F dew points.

 

[oldgoaly]

Sourdough,
there are some with a dip in the rear flange for a drain. not a hole. But if the op reads the instruction there won't be a problem. He is in Wisconsin so taking it out in September putting it back in April, will save him a few bucks on heat! it was -18 here I'm about 300 miles south, I know it was colder longer up there. As you are I'm semi-retire 27 years with my name on the business. tt

 

[sourdough]

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@oldgoaly

Sourdough,
there are some with a dip in the rear flange for a drain. not a hole. But if the op reads the instruction there won't be a problem. He is in Wisconsin so taking it out in September putting it back in April, will save him a few bucks on heat! it was -18 here I'm about 300 miles south, I know it was colder longer up there. As you are I'm semi-retire 27 years with my name on the business. tt

With all due respect, I fail to see how removing a large unit such as this in the Fall and re-installing it in the Spring will accomplish much insofar as energy saving. In the first place, many mods must have taken place to get that large unit set in the existing window (or other) opening without much modification, and therefore the removal of the unit for the winter will again entail much window modification in order to seal up the penetration.

Why not just seal the unit in place and cover the condensing unit from the elements?

I live in SW WA State where the temps rarely get below 0*F but I believe the basic precepts still hold true. The nasty summer temps can be as high as 105* and normally 90*-105+* in July and August.

 

[oldgoaly]

Well having lived in a house for 10+ years with 2 ton pm in a window, the metal conducts very well the heat out but gives the feeling the cold is coming in. Covers help but a good window is better than the a/c unit. We would even cover the inside trying to save heat!

Location, the east side of your shop, one hail come mostly straight down or from the south and west. Also you won't have the sun beating down on it during the late afternoon. If you do leave it in the north wind won't be beating it all winter!

ps spent 3 days in Seattle end of July 1st of August. 80 degrees and Sunny all 3 days, that was the talk of the town 3 days of sunshine!!!!

 

[FloydShine]

Find yourself a good deal on a de-humidifier to put in the shop too

 

[Richard Cranium]

A ceiling fan or two would also help it cool your garage. The plus is when it is not hot enough to run the a/c you can just run the ceiling fans to cool...

 

[JonnFX]

I have a detached, pretty well insulated, 1000sqft shop with a 10ft dywalled ceiling and drywalled walls. I added some 1.5" Styrofoam panels in my roll-up door. I have two whirlybird vents and one powered vent in the attic area.

Two summers ago, I switched from my prestaged single pad swamp cooler to a wall 18,000btu AC unit. It works pretty dang well. I live in Arizona and on a 112° day it won't get it chilly, but definitely down to a workable temperature. I do have a few fans that help, also.

When the nights are cool enough, I run just the fan on the swamp cooler (like a whole house fan) to give the AC a head start.

I wouldn't mind a slightly larger unit, but I'm happy with this one.

Good luck.

 

[oldgoaly]

John,
a swamp cooler in the midwest? humidity exceeds 50% many days! almost every night during spring, summer, and fall! might as well turn on the heat at least it will be a" dry heat!" keeping it (shop /garage / shop) closed up running a dehumidifier? but that adds heat, removes moisture, might as well run an a/c unit get rid of moisture, cool the air. I have run a dehumidifier in the spring, when we have heavy rains and still cool, the brutal heat has arrived.
What helps is a whole house fan, the is my shop fan. cheap from an auction.

 

[JonnFX]

I'm not suggesting a swamp cooler for anyone, as I just stated what I have here in Arixona. Also, like I mentioned before, I use it on cool nights as a whole house fan.

Since it is so dry here in Arizona, mine works OK a lot of the time, but now I mostly just use my AC.

Yep, I grew up in Illinois with the "not so dry" heat. The dryness makes a world of difference, but that doesn't mean I like to sit around in 112°. Although, I'll take 100° and dry most any day.

My prestage setup attached to my swamp cooler will drop the temperature up to 7° without adding humidity and uses very little energy. Even when I used the swamp cooler, I didn't have a rust problem, since it wasn't running 24/7.

 

[sourdough]

ps spent 3 days in Seattle end of July 1st of August. 80 degrees and Sunny all 3 days, that was the talk of the town 3 days of sunshine!!!!

Well, those folks that live in sea-level Pugetropolis grow moss in their armpits. I'm located 100+ miles SW of Seattle at 600' elevation in the Willapa Hills: the weather here is quite different.

 

[Highbeam]

Well, those folks that live in sea-level Pugetropolis grow moss in their armpits. I'm located 100+ miles SW of Seattle at 600' elevation in the Willapa Hills: the weather here is quite different.

They call use mossbacks for a reason. I am also up above 700 feet but closer to the sound, in the valley sorta. It's wet and not much different up here.

 

[Jim Sperry]

I can't wait for a true dehumidifying mode on a thru-wall [or any portable AC]. Set it for 50% humidity and 78˚.