best AC for detatched shop

[LutzTD]

Im dieing in the shop from the FLA heat. I have looked at 3 options and wonder if anyone has experience. First and second is a mobile home package unit or a wall hung package unit. These are all in one so hook up electric, run some ducts and its all done. These exchange their air as well as cool it. I would run it as a dehumidifier most of the time and then crank it up when im out working. Second option is a mini split system. Some of these have really high SEER ratings, like over 20 since they use an inverter to control the speed of the compressor rather than turning it on and off. They are easy to install but I woud need an AC guy for the exchange gas hookup. what I dont like is they just keep cooling the same stale air. anyone have any experience with either of these or a different setup?

 

[RedVise]

what I dont like is they just keep cooling the same stale air.

In Fl, you want to keep cooling the "same stale air", you dont want to cool the hot humid air from outside.

Brian

 

[LutzTD]

In Fl, you want to keep cooling the "same stale air", you dont want to cool the hot humid air from outside.

Brian

thats true, it is just a shop. I will have a weldhood to **** out stale air as needed.

ductless +1

 

[JMURiz]

I use a Mr Slim minisplit. When it's really humid I run the dehumidifier setting and it's quite nice. IF I'm out there doing some really hot work I turn on the AC, but that's rare.

 

[Gary S]

First, how is your insulation?

 

[theoldwizard1]

Insulate first.

Inverter mini-split second.

 

[TOOLGUYNO8]

Hi, I use a mini split and Mr. heater radiant heat in my 24 X 34 garage and they both work great.

 

[Doug1]

A mini-split would not work for me. I went with a roof mount heat exchanger and in attic ducting for a clean installation. No footprint on valuable squarefootage next to the garage wall, unseen, unheard and it will whip the temp down to 76 from the 84 I keep it at in about 15 minutes. It's fast to cool...and that's important. If you have to go out and crank up the split system two hours before you need it...you'll hate that.

It's a LOT different here than Florida. I am speaking of installation and general useage.

I have a mini split in a 400 sq ft sunroom and it will take the temp from the 90s to the low 70s in a hurry. Less than 15 minutes.

In the shop, I am just using a large window unit mounted in a wall, which works but not all that great. The cost difference between the two systems is roughly times 6.

If you can afford the mini-split, go for it. I need to get something nicer for the garage and don't mind putting in a wall unit so I need to look at those types of units when I upgrade. Anyone have any idea what the in wall units cost?

 

[1/2 Cup]

Insulate first.

Inverter mini-split second.

Same for me, I use it year round for both heating and cooling. I also have a ceiling fan in my work area for those more temperate days.

 

[Jamie V]

I'm not a mini split guy, but that's because I fabricate ductwork for a living. Here are my 2 units in my basement.



Ductwork puts the air where it needs to be so the building can hear and cool evenly. Do you ever see anyone heating their shop with radiant heating only pipe 1/2 the floor? No, you want even heat across the entire floor. Same goes with A/C, best is full coverage.

 

[Bobdog]

My two cents...........

Go with the mini-split.

 

[Nowater]

I am not that far from you and I use a window unit "wall shaker." My shop is well insulated and fairly air-tight which makes a big difference.

 

[Falcon67]

No size stated but a decent large window unit mounted high on a wall works well if the building is insulated and reasonably air tight. I have two rooms and if I had the cash for a dual inverter mini, I'd buy one real quick.

 

[Mike007]

I went with a through the wall unit for a few reasons. 1, it was cheap. 2, I only run it a few times a year so I'm not to concerned about efficiency. 3, it was a quick install. 4, when the coils get dirty (there's a lot of dirt flying around in a shop) I will unplug it, pull it out of the sleeve and pressure wash it and throw it back in. Quick and easy.

 

[LutzTD]

I hear everyone on the insulate. I am going to seal all the cracks in the coming weeks. But I wont be able to do much on the insulation front. I want to add solar to the roof so I need to access the bottom of the steel roof for the supports. Once thats done I can add insulation to the metal roof. The block walls are what they are. I thought about styrofoam then stucco but I just dont want to create a roach (or Palmetto bugs for the sensitve tyoes) condo system or a mouse colony. I really want just the AC for quick cool down while im working, and to dehumidify when Im not to protect the machines. I dont need to keep it 75 degrees, I just need it to not go to 110 then back down to 70 at night then back to 110 with all the humidity. If I set it at 85 it would still likely run a lot to keep humidity down but I think it would be manageable The room is 20x40 block with a single 4:12 pitch from about 8 to 14 feet. fwiw the block walls are pretty much always cool to the touch, so I dont see those being as much issue, but the metal roof is like a 24x40 hot plate in the day time. You cant even touch it.

 

[LutzTD]

A mini-split would not work for me. I went with a roof mount heat exchanger and in attic ducting for a clean installation. No footprint on valuable squarefootage next to the garage wall, unseen, unheard and it will whip the temp down to 76 from the 84 I keep it at in about 15 minutes. It's fast to cool...and that's important. If you have to go out and crank up the split system two hours before you need it...you'll hate that.

It's a LOT different here than Florida. I am speaking of installation and general useage.

is that a water evaporation system? My friend in Col Springs had one of those and they are nice, but Im afraid they only work in the desert. Our air here is so humid I think it would add water to the exchanger

 

[LutzTD]

I went with a through the wall unit for a few reasons. 1, it was cheap. 2, I only run it a few times a year so I'm not to concerned about efficiency. 3, it was a quick install. 4, when the coils get dirty (there's a lot of dirt flying around in a shop) I will unplug it, pull it out of the sleeve and pressure wash it and throw it back in. Quick and easy.

Yeah I thought about cutting a hole in my man door for a through wall system. My block is so full of rebar and is solid filled so I would be hard pressed to get a hole that size through. Even 6 inch ducts would be a challenge.

 

[36racin]

LutzTD,
After the solar installation I would have the foam insulation sprayer come in and have them spray the underside of the roof metal. That would definitely insulate the building quiet well and you could get away with a lesser A/C unit.
The mobile home A/C unit or a commercial package type unit would work well. You can find either on craigslist fairly cheap from time to time.

Todd

Ok I just went back and looked at your shop build. I love the shop. Alot of quality tools and rides are going to be in it too.

 

[coolreed]

I am putting in a Mitsubishi Mr. Slim Heat Pump in my 900 Ft^2 garage.

 

[pseudorealityx]

A mini-split would not work for me. I went with a roof mount heat exchanger and in attic ducting for a clean installation. No footprint on valuable squarefootage next to the garage wall, unseen, unheard and it will whip the temp down to 76 from the 84 I keep it at in about 15 minutes. It's fast to cool...and that's important. If you have to go out and crank up the split system two hours before you need it...you'll hate that.

It's a LOT different here than Florida. I am speaking of installation and general useage.

Mini splits are available in ceiling cassette styles that allow you to duct it like any other system. Having a 'split' system vs. a packaged unit makes ZERO difference as far how fast the unit can cool.

 

[LutzTD]

So heres where I am now. I like the mini splits, but since they are tied in I need to modify my permit and add the cost of professional install. They DO NOT allow homeowner installed ac here. If Im going to do this Id like to get something for the whole shop, maybe later. So for the current shop I need a somewhat temp solution. So my next best is a portable unit or a window unit, neither of these is considered installed so are not permit driven, and later it can be used in my other outbuilding or sold. I have a 30" square hole through my wall I could put a window unit in but that is for a fire escape and it is 12 feet up the wall. I think it would be OK (just push it out incase of fire escape need) except the thermostat would be so high that it would run forever. My thought is: could I make a plenum for the back side of the window unit, I put it down at about 6-8feet from the floor over my machines? Has anyone done anthing like this. I was thinking to put a box around the end with a grill on the bottom, then a suction fan at the top of an 8" duct shooting out under the eave. Am I crazy? I guess I will try it in the square opening first. Maybe it will work out OK there and save me all the redneck engineering. HD has a 24500BTU window unit with remote for $599, thats about 1/3 the installed cost of a 24000BTU mini split, the efficiency is 1/3 too though

 

[36racin]

Take the window unit grill off and install a rectangle duct work and pipe the air into the shop where ever you want. The return will be back thru the filter on the window unit. But you are going to have to do something with the roof. The A/C is going to have a hard time keeping up with a bare metal roof.

Todd

 

[LutzTD]

Take the window unit grill off and install a rectangle duct work and pipe the air into the shop where ever you want. The return will be back thru the filter on the window unit. But you are going to have to do something with the roof. The A/C is going to have a hard time keeping up with a bare metal roof.

Todd

I think the key for the short term is to find a window unit with a remote thermostat. Then the roof wont drive it as mush I think. As long as I can get the bottm 6-8 feet reasonable stable I will be OK.

 

[LutzTD]

I decided for $130 I can add a radiant barrier under the roof. If I need to remove it later its not a huge cost. I will screen the upper opening and hopefully it will also **** out the hot air as well as providing a radiant barrier. I will post in my build when I do it to see the results

 

[TangoFoxTrot]

A split unit would be best if money was no option, but if I were you I'd put as big a window AC unit as you can fit and a large industrial ceiling fan.

You're not trying to make a space that needs to be 75 degrees year round, just something so you can work without passing out from the heat.

I had central AC in an insulated garage, and honestly, a strong fan did more to keep me cool. As soon as you'd open the garage, all the cooled air went out and you had to start all over. I usually liked the garage open for the light, which you obviously can't do if you want the AC to run.

 

[Beach Dude]

So heres where I am now. I like the mini splits, but since they are tied in I need to modify my permit and add the cost of professional install. They DO NOT allow homeowner installed ac here. If Im going to do this Id like to get something for the whole shop, maybe later. So for the current shop I need a somewhat temp solution. So my next best is a portable unit or a window unit, neither of these is considered installed so are not permit driven, and later it can be used in my other outbuilding or sold. I have a 30" square hole through my wall I could put a window unit in but that is for a fire escape and it is 12 feet up the wall. I think it would be OK (just push it out incase of fire escape need) except the thermostat would be so high that it would run forever. My thought is: could I make a plenum for the back side of the window unit, I put it down at about 6-8feet from the floor over my machines? Has anyone done anthing like this. I was thinking to put a box around the end with a grill on the bottom, then a suction fan at the top of an 8" duct shooting out under the eave. Am I crazy? I guess I will try it in the square opening first. Maybe it will work out OK there and save me all the redneck engineering. HD has a 24500BTU window unit with remote for $599, thats about 1/3 the installed cost of a 24000BTU mini split, the efficiency is 1/3 too though

If you have a Sams club membership, I just purchased a GE 24000 btu ac unit for 424.00 on line only. Just put it in last week. I'm probably 45 minutes or so from you, get the humidity down and it helps a lot.

 

[LutzTD]

If you have a Sams club membership, I just purchased a GE 24000 btu ac unit for 424.00 on line only. Just put it in last week. I'm probably 45 minutes or so from you, get the humidity down and it helps a lot.

I never even thought of Sams, good call. Ill look today. Thanx

 

[LutzTD]

Walmart had a GE 24000BTU with remote for $384. I ordered one for store pickup.

http://www.walmart.com/ip/General-E...-Star-Window-Air-Conditioner-AEW24DQ/20449875

 

[Beach Dude]

Nice find, I missed it when I was looking for mine.

 

[LutzTD]

Nice find, I missed it when I was looking for mine.

not sure is its the same as the Sams one, it has a different model number, but thanx to you I checked Sams and Walmart since it is the same company. It looks like they just lowered the price, its listed as a price drop, so likely it was more when you looked

 

[Beach Dude]

The digital readout on mine is in the upper rt corner versus the upper left on the walmart link, if it works, who cares, just glad to have a tidbit of helpful info, I don't post much, but read the post's a fair amount.

Nice looking Shop and Nice write up.

R.J.

 

[Mystic_Cobra]

Hi, I use a mini split and Mr. heater radiant heat in my 24 X 34 garage and they both work great.

I was considering the same for my 21x24 attached garage. Did you compare costs to other types of HVAC? A friend of mine who does home renovations said I should consider a larger AC condenser (mine is 27 yrs old and getting replaced this year) and get two air handlers. thoughts??