Air Conditioning Your Shop

[David Hostetler]

As I have posted on before, 13.5K BTU portable unit, ducted through the wall between the overhead doors. Still getting too much heat gain through the one uninsulated door, and the uninsulated walls, but I can drop the temp in my shop by about 10 degrees in an hour, but more importantly, dump the humidity to tolerable levels QUICKLY...

[Jason White]

Just purchased a used 12000 btu window unit that I found for sale in the classifieds. Some cleaning and a few drops of oil in the fan motor and the shop is now quite comfortable! Ahhhhh.....

Well, in the winter, we had all kinds of discussions about heaters. Most agreed that you didn't need HUGE heaters. Most were satisfied with a unit that was rated for much smaller than their actual shop square footage. What about air conditioners? What have you all found?

[Greg Carr]

I have a 12,000BTU window unit in a 400 sq ft attached garage with insulated walls. It works better than I expected. I recently replaced my 16' uninsulated overhead door with a 2" thick R13 door and sealed it up real good all around. Also replaced the side entry door and installed a vinyl replacement window. Energy tax credit Last weekend it was 104 outside and I was able to get the garage from 94 to 78 in just over an hour. I have no problem keeping it below 75 when it is 90 outside. I get the full evening sun on the garage door. I get to spend a lot more time out there now.

Greg

[Ted Jay]

I'm in the same conditions as Alex and David being in the Houston area. The humidity is a killer and the heat index will get to 107 as it did last year, but my concern is mostly with the humidity. I have a 24x30 shop, and with utility prices rising, trying to run an A/C in the shop gets expensive.

I was thinking I would like to do a couple solar panels and a battery bank just to run a split unit or a PTAC (motel type) A/C.

After doing some searching online I discovered that in order to make it more efficient for solar power I should use a DC unit instead of converting battery power to AC, which uses more power.

I have found a couple sites that are advertising Solar A/C units that won't be availiable for a few more months, no prices though, so they are probably high. Anything touted as "green" nowadays are high priced.

[Daryl Henderson]

It seems that the temp in my area is either 10 or 110! Sometimes in the same day. I used fans for a while, even bought a small evaporative cooler on wheels for a while. It is dry here, but that only worked while it was blowing on you and you kept it full of water. I used small propane heaters, but that was not adequate in the dead of winter.

My local HVAC guy had a 1 year old 3 ton central unit that he installed in a house and was not large enough for the homeowner. He installed it in my 30 x 30 shop for $800.

On a 100 deg summer day, it takes about 30 minutes for it to cool to about 78, and then hold it without running very often, but that depends on the number of machines running.

I built the return box with a double filter. The first a standard furnace filter and the second a 2 micron filter after that. No problems with clogging so far, and it acts as another air filter.

The entire unit is about 3.5 ft square and 7 ft tall with the plenum on top to direct the air, no ducting.

[Neal Clayton]

That is the unit I was looking at. I went with the 8,000 LG. I read a bunch of reviews and most folks were happy. The one complaint, when the was one, was that it was noisy. Mine is quite quiet. I just think I'll have to add another.

Steve, did you add any type of external filter? The filter that it comes with that is just inside the intake grill seems to be, well, a joke. But, of course, these things weren't designed to be in a wood shop... I am planning to make an frame around the intake grill and put a filter on it...something that will actually catch any dust and hopefully prevent ruining the unit.

i'm on year two of my LG window units now, and they're still working ok. the drain holes they have in the pan are insufficient, so you'll probably have to drill those out at some point as the units fill up with not just sawdust but dirt from outside too. that's a pretty simple fix, though. other than that mine are working fine.

[Mike Cruz]

Dayrl, I wanted to do something just like that. My HVAC guy said he could get me a unit for $500-$800, too...but the kicker was the instalation charge. That is what put it over my limit. Think your guy would like to come over here and install one for me?

[Daryl Henderson]

He' probably would. He is retired as of last month so he would enjoy a trip to Maryland--All expenses paid of course. I'll even come be his helper!!

[Mike Cruz]

Daryl, not sure you'd want to be here right now... Yesterday was 99. Today it will be 101 with a heat index of 108 (our humidiy has been awful) and tomorrow looks like it will be 102! Thursday will be back to a chilly 90....ahhhhh

On the A/C topic, here's an update..............

The 8000 btu unit I put in my 24x30 stand alone shop (which is now insulated) had a bit of a time when I first turned it on. It ran for hours.... I had it set on 80. But the inside shop temp when I set it up was well over 90. We got lucky with a few very cool mornings (ranging from 50 to 57). Each morning, at about 5 am when I got up to take care of the horses, I opened a front door, put a fan on the floor and drew in the nice crisp morning air. I also put on the exhaust fan that is at the top of one of the gable ends to get the hotest air out. I was able to get the shop down to 65 this way by about 7 am.

What I was fighting wasn't the air temp in the shop, it was everything else in the shop that was still hot. So, after the multiple mornings of cooling, I was able to have the A/C unit set on 78. I have it in Energy Saving Mode. Which means that the unit kicks on every 10 minutes or so and checks the temp. If the temp hasnt' risen (more than a degree or two) then it shuts back off. If the temp HAS risen, then the compressor kicks on, and it does its "thing". If you just set the unit for, say 78, the fan will run constantly, and the compressor will kick on and off when it needs to. I don't feel a need to have the fan running all the time, so that is why I put it on ESM.

The test? Yesterday was 99 and humid. The unit is NOT running all the time. Yes it does need to come on from time to time (expected) but it actually does the job! I have to say that the other end of the shop is at about 82 or so, but I can handle that!

At some point, I may add another unit on the far side of the shop so that this one doesn't get over taxed. It certainly is not meant for this size room/building.

[Kevin Gregoire]

i want to know if anyone is cutting a hole in your walls and using a window unit? if so,
how are you mounting it if you dont install a window?
window units are so much cheaper then through the wall types and can be found used
much easier.

i dont have any experience and im still yet to install air but i want to cut a hole in the wall
and frame it and mount a piece of 3/4" plywood on outer wall and cut exact hole in that
to match a window air unit. i would think that should work but i dont know how far in
it would protrude so it dont look funny sunk into the wall?