Air Conditioning Your Shop

[Mike Cruz]

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?

[Ray Bell]

I installed a 18K, BTU Soleus split unit last fall. It kept the shop very warm, and it is wonderfully cool in there now.

[Mitchell Andrus]

Window unit, 12,000 BTU. It would be a little undersized if the shop was a really large living room or group of rooms, but fine for the shop because on a 90 degree day, a 10 degree drop (80 degrees) is comfortable and that's an easy reach for a 12,000 BTU unit in my size shop. If I shot for 72 degrees on 90 degree days, It'd be running full time and never get there.
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[Roger Newby]

Same set up as Mitchell. 80 degrees is the worst inside I've had so far. Also keeping the humidity at bay is fairly easy. I don't shoot any lacquer until fall if I can avoid it, but I can crank the AC a little more if I need it. Plan on cleaning the filters real often just to keep the unit running comfortably. Fine saw dust gets in there real easy even with collection.

[David Prince]

Central Forced Air System. I just keep an eye on the filter to make sure it doesn't plug up. I also have a air cleaner and DC, so the dust is minimized. It has worked fine for heating also.

[Mike Cruz]

My shop is 24x30, so 720 square feet. But with 10 feet to the bottom of the rafters, and then exposed ceiling above that, I have more than what would normally be 720 square feet for the charts. I was looking at an 18,000 btu window a/c unit for $400, but came across a small snag...my windows seem to be a bit tiny. The largest unit I could fit in any of my windows (they are all the same size) is an 8,000 btu unit. It is rated at something like 350 square feet. Well, the shop started off at 89 degrees at 5:15 pm. By 9 pm, it was 81! Not too shabby. But I do realize that I will likely need a second unit.

Also, what I know I was fighting was more than air temperature. Everything (floor, walls, equipment...everything in the shop) was 89 degrees at the begining of the test. So, with some much needed cool temps setting in tonight (59!) I have a couple windows open to cool the shop off over night, and I'll see if I can KEEP the shop cool at the high 70's. Shouldn't be a problem...

[Steve Kohn]

I have a 840 square foot shop, well insulated, with exposure to south and west sun. I just put in a 18,000 BTU window unit from LG in the only window I can; on the west side of the shop. Outside temperature was reading 89 degrees at the same window, and the inside was at 76 degrees. The unit was still cycling on and off. I'm a very happy woodworker now that my sweat isn't staining my wood or my cast iron.

[Mike Cruz]

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.

[Joe A Faulkner]

Ray, I've been thinking that I can take the heat, but need something for the cold Indiana winters. The split unit you mention sounds interesting. How large is your shop? How well is it insulated? Ceiling height?

[alex grams]

I have an 18,000 btu window unit that I had a jerry rig since I have no windows.

I basically built a carcass around the window unit, isolated the inlet and outlet for the condensor cooling, and then cut holes in the top of the carcass into the attic for each the inlet and outlet, then built a duct from the ceiling to the awning vents for each the inlet and outlet. I also added an additional mushroom vent for the suction to help relieve any head loss for the suction of the fan.

Not sure how many building codes i violated, but the unit will go with me when I leave, and i will just sheetrock up the ceiling holes then.

Works great, and a 18,000btu window unit for 350$ is a heck of a lot better than a split unit of same capacity for over twice the price. I believe mine is the fridgidaire brand from Lowe's.

You can see the unit in the overhead in the picture. Not the best picture, but it shows the unit.

I am in the same world as you Mike. Houston humidity is brutal. You said you had an open ceiling to the rafters? I would heavily consider adding a ceiling and insulating it.

I only run my unit when I am in the garage, not full time. I can drop it about 5-8 degrees with a big change in humidity in about an hour, which makes a world of difference. The drop in humidity makes it more comfortable to work in than the drop in temperature (in my opinion).

Good luck.

[Gary Venable]

My shop is the small third bay of three car garage. The walls, ceiling and doors are all insulated. I am using a 12,000 BTO portable AC unit. Due to restrictions I could not have a window unit, so I cut a 4 inch hole and mounted a dryer vent and hooked the units exhaust to that. The unit has a mist pump that sprays the condensation out with the air exhaust so I have not had to drain the system ever. It is in the middle of its second summer with no issues. Keeps the shop very comfortable to work in.



-Gary

[Ray Bell]

Ray, I've been thinking that I can take the heat, but need something for the cold Indiana winters. The split unit you mention sounds interesting. How large is your shop? How well is it insulated? Ceiling height?

Joe,
The building is 20'x24', with 8' ceiling. The walls and ceiling are insulated. The weak point is the 18" garage door. I do intend to insulate the door someday to increase the efficiency, but as far as unit operation it doesn't matter. Even with this door I have to adjust the temp to the low setting.

Somebody mentioned auxiliary filtering. This is a must in my shop. Even with the dust collector the split unit sucks up a lot of fine dust. I have several Purolator, cut to fit, washable filters that I change out when I can see the dust building up. So far I just tape these on the outside of the grill. Someday I will build a frame for this.

[Mike Cruz]

Alex, I don't think I'll be creating a ceiling anytime soon... I JUST put up insulation up at the roof. This is a detatched building, not a garage, so I don't have large bay doors opening and letting in a huge amount of hot air.

[Steve Kohn]

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 haven't had the unit long enough to check the filter yet. I spent a lot of time sanding last weekend and will check the filter the next time I am in the shop. The suggestion of adding filters in front of the unit is probably a good one, especially if you also spray finishes in the shop.

Another question for all those with window units. Are you planning on pulling the unit during the winters or are you just going to buy a cover?

[alex grams]

I bought some cheap 3m filters and put in front of my unit. The dust isn't that bad, but when condensate starts forming on the coils the dust will cake on pretty heavy and can cut down the efficiency quiet a bit.