Shop air conditioning

[yyz]

Has anyone installed AC in their shop? I have a single, 10 x 20' garage stall separated from the rest of the three car garage that needs some cooling relief from the Texas heat.

I got a quote from a local HVAC contractor for a 12,000 BTU Mitsubishi unit for close to $4000. From my little bit of Googling, I think I can get away with a 9,000 BTU unit and don't want to spend nearly that much.

Any help would be appreciated!

Mike

[Gene C]

That is roughly the size of my shop so Thanks for after checking the BTU/HR rating the evaporator needed a cleaning before turning it on later this summer. The old Sears Coldspot window unit is rated at 18500 BTU/HR and does a good job of cooling the shop during the very hot days. WOW! they got expensive, must be the environmentalists.

[edfmaniac]

No way you need that much horsepower to cool that space unless you are using shower curtains or sheets for walls/insulation, especially if the garage gets some ambient cooling from being attached to an air conditioned house. But even if it's a stand alone garage, as long as it's mildly insulated, a $350 window unit will keep a 10x20 area nice and cool. I use an 8000 BTU unit to keep two bedrooms and a bathroom chilled down and occasionally switch on the 5000 BTU unit when we get multiple 100 degree plus days in a row and I'm feeling like a polar bear.

We also used a sub 10,000 BTU unit to cool the 20ft shipping container we converted to an rc race car pit space at Thornhill Raceway outside of Hutto. It would cool the hot container down within a half hour of switching it on. No windows of course so we installed it in the wall that we built for our screen door when the container doors are open and we mounted the unit on drawer slides so it would retract we we locked up container doors at the end of race day.

You can get a 12,000 BTU Frigidaire at Home Depot for $400.

[SMYK]

Hot subject
I am from northeast bu still needed the AC in working area. After several turns with window units once fall in my hands little used portable 13500 Btu Friedrich with heat pump for colder days for $300. Very fancy and efficient. It takes little space, but could be directed or moved where is needed. Needs attachment to the window or other exhaust/intake airflow. I use my laser cutter venting ducts. In the shop dust is the issue as well. Having an AC hooked up to the good filtration system makes a joy to spent time there. Right humidity and air crystal clear in the morning priceless

Mike

[edfmaniac]

I've owned a couple of the portable indoor units that expel their waste heat through a hose in the window, but my experiences have been that they are less efficient because they draw a negative pressure in the room with their exhaust fan, pulling in outside air through every tiny gap in your insulation. Regular window units don't create positive or negative pressure in the room so more of the cool air stays inside and more of the hot air stays outside. In my experience.

[Asher Carmichael]

Mike,
I’m running a Carrier 2 ton ductless mini-split heat pump system in my 20’x32’ shop and it is fantastic! Mitsubishi is considered the top of the line so you’re paying for that. My dealer gave quotes for a 1.5 ton @ $2600 and the 2 ton @ $3200. I went with the 2 ton since it was a bigger space but a smaller space should be fine with the smaller unit. The nice thing about ductless systems is they can be serviced, incorporate heat pumps for efficiency, are reliable, can be timed for operation, are bluetoothed for off site control, can hardly be heard when running, etc. etc. I can turn my unit on in the middle of a 95 degree day with 85% humidity and it’s down to 75 degrees in 20-25 minutes. Same level of operation when heating in winter. Give me a call if you need further info.

[SMYK]

edfmaniac
There are many shades of portable units. Do not fall in marketing stereotypes. I do not know why market is filled with these single hose units. Principle of these runs against basics of the physics and against science of heat transfer.
In my statement I am talking about real portable AC unit. Did I said Friedrich, fancy, efficient with the heat pump. It must have two hose system to operate properly. Otherwise I would never consider of using it. Original costs is $1800 and is intended for commercial office spaces. In my garage everything must be portable. I am changing my mind way too often.

Split units
Contractors charge a lot for split units based on average consumer appraisals. There is not much involved to install them. This is how they make money because people want them.
For a garage with simple installation best bet is to look for DIY split AC kit and install it for fraction of the contractor quotas

Mike

[Scalesoaring]

I have a 12 x 18 well-insulated 3-year old shop. I use a portable 10K BTU floor unit ($349.00) located in a blind corner under a workbench. It is vented through the wall (with the drip hose). We get 100+days but typically in the 80's and 90's and it does the job. Negative pressure brings in fresh air.