# Best method to cool my 2-car garage/workshop in summer months



## jnovak (Apr 12, 2019)

Hello woodworking friends,

I may have posted a thread on this forum about this subject awhile ago…but can't seem to find it.

My wood shop doubles as our 2-car garage. I have a majority of my tools in a mobile state and I'm pretty maxed out on what I want/need in my wood shop. I have an overhead gas furnace in the garage (approx 24' x 22') and it does a great job of heating the space in the winter time.

However, in the summertime up here in Minnesota it can get very warm and humid and I have to pretty much shut down my wood shop for the summer because it gets to be unbearable working in the shop.

I'm just starting to look into some cooling units but I don't have a huge amount of available floor space and I don't want to spend a ton of money to try and cool it. Does anybody have any suggestions as to what might work in my situation? I've seen units that heat AND cool but they are expensive and I don't need the heating side of it. I've seen these wall mounted cooling units in businesses but not sure how well they work.

I look forward to any suggestions/ideas.

Thanks.


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## CWWoodworking (Nov 28, 2017)

If it's insulated, just get a window unit. The size is small so it would work fine.


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## tvrgeek (Nov 19, 2013)

You did not say if it was a dedicated space, or if it is sometimes a garage. 
So, are you looking for full time cooling, or just when you want to work? 
If un-insulated, takes a decent size unit.
Garage doors leak. If dedicated, you can tape them up. 
Modern high SER units do not de-humidify very well.
Those wall mounted are called mini-splits. Most are heat pumps, but some are cool only. They cost a lot more than a window unit, or through wall mounted window unit. 
A related subject is your dust management.

Woodworking is not cheap. Pay to play. Of course we don't want to spend a pile of money, but sometimes that is what it takes. I got by with just a ceiling fan and worked early and late so not in the heat of the day. I did have a lot of issues with tool rust though.


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## jnovak (Apr 12, 2019)

My wood shop is shared with my vehicles and I do not have a window in my garage so a window unit is not an option. I've looked at mini-splits but, as you stated, many of them are heat pumps as well and I have no need for that.

The garage/wood shop is well insulated…walls, ceiling (sheetrock with lots of insulation blown in the attic) and garage door. I really don't want to spend a ton of money…but if I can find something that I know works well then I may be willing to adjust my budget.

Thanks


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## Nicky (Mar 13, 2007)

You may want to look at a portable unit. I had a window that I closed and mounted a 5000btu window unit. A portable would require a vent of some sort (4" hole). Today its been mid-90 and my shop is very comfortable.
My shop is about the same size as yours and well insulated, including the garage door. The window unit I have is undersized for my space. We put in central air in 2014and the unit was taken out of my home and installed in my shop. If it dies, I'll get a bigger unit. Keeps in mind that an a/c unit will require regular cleaning of its filter. I also have a bathroom type fan mounted in the ceiling to help get rid of the hot air that rises.


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## Knockonit (Nov 5, 2017)

single door, or double door, if double, well maybe make a short closure and put the ac unit in the area under the partially open garage door. just make a closure to keep the cool in, easy to remove and store till next time.
or cut a hole thru wall in a decent location and put a wall unit in, no real easy way, just install unit perhaps under overhang, and away from rough weather. or put a all weather cover over it during those ugly winter months. 
good luck, dang wood working always creating issues to over come.
rj in az


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## ibewjon (Oct 2, 2010)

Mini splits do de humidity if properly sized. And it may cost less to run the heat pump than your gas heat, depending on your electric and gas rates. If you use propane, most likely cheaper to use the mini split heat pump. Just keep the filter clean. Way more efficient than a window unit. If you have an actual gas furnace, not just a gas heater, you may be able to add ac to that. I am pleased with the operation and cost of my mini here in Illinois, an hour south of Chicago.


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## CaptainKlutz (Apr 23, 2014)

This is a popular question this HOT summer!

Since every persons shop is different, there can be a lot of satisfactory solutions. 

Please search forums for garage AC and/or Minisplit, Mini-split.
There are a ton of existing threads that beat this topic to death.

Such as this one.

Cheers from someone tired of posting the SSDD.


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## Lazyman (Aug 8, 2014)

I used a portable AC unit until a couple of weeks ago (replaced with mini-split). When I first started using the portable unit, I vented it under the door by laying 2×4s on either side of the piece designed to vent through a window. There was lots of leaking air but it did work well enough to take the edge off in all but the hottest or coldest weather (it was a heat pump too). I eventually added 2 garage door exhaust ports so that the door could be closed and weather stripped for a good seal. Note: for the best performance, get a portable unit with 2 hoses so that you do not use conditioned air for the exhaust. Single hose units not only use cooled air for exhaust but will also suck hot air from the outside into your cooled space through cracks making it much harder to keep it cool.


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## Tony1212 (Aug 26, 2013)

> My wood shop is shared with my vehicles and I do not have a window in my garage so a window unit is not an option…
> 
> - jnovak


You can cut an opening in a wall and mount the A/C unit permanently. You just need to frame it like a window with the proper size header, jack and king studs and all that. That may be cheaper than a mini-split. And probably less work than installing a mini-split yourself.


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## Lazyman (Aug 8, 2014)

MrCool DIY mini split was easy enough to install myself. The hardest part for me was making a 3.5" hole through brick veneer on the outside of the garage. Would have been very easy with anything but brick. Of course you need to add a new power circuit and disconnect too. Not cheap but definitely a huge step up from the portable unit. Or check out the Klutz's portable minisplit in his link above or go straight to it here.


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## squazo (Nov 23, 2013)

Minisplit. 12,000 btu. $1,500


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## therealSteveN (Oct 29, 2016)

Something in a floor fan, costs much less, and allows for moving air. Most run on 110, and don't require anything past plugging them in, and flipping them on. Roasting in stifling air sux, get the air moving, and it's much more tolerable.

You have the same need to then wear eye protection so flying dust doesn't get in your eyes, nose, and mouth as you would with a mini blowing expensively cooled air around.

Practical first step, and so much lower cost, not to try it first seems kind of silly IMHO.


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## Kudzupatch (Feb 3, 2015)

This is what I am doing. Last few weeks in the 90's and at least 70% humidity. Not ideal but with a big enough fan it is bearable.










I picked up a couple of 220V fans scavenged from old HVAC units that were replaced. You can get them free if look around. Check with HVAC company and they may let you remove one from an old unit that are about the scrap.

Moves a HUGE amount of air. Actually had to block off the outlet some to be able to stand in front of them. But a big fan with enough air flow makes a huge difference.

If this were my permanent shop like your is. I would just cut hole and frame up like a window and put in a window unit A/C. My shop is just a make do till we build the house. Then it will revert to storage/garage.


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## BurlyBob (Mar 13, 2012)

This is what I installed last week. I was given that AC unit. All totaled I'm into this for around $75. The only downside is that is really noise inside the garage. I've only got the 2 windows as the other side of the garage is next to the alley and the back faces the neighbors.










Like Tony mentioned it would not be hard to frame in a window for a unit like mine.


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## OzarkJim (8 mo ago)

Hands down the Mini Split. If you have the money to make the initial purchase. It will last a lot longer than a window unit, doesn't require a big hole in your wall and is far more efficient saving electric costs!! Even if I was only going to use it to cool I would still get the mini split. Long term the mini splits are the most cost-effective way to heat and cool your shop or house.

I am so sold on them that I bought a vacuum pump and A/C manifold to do the installs right (you don't have to do it but it is best practice). We replaced our central unit and a giant window unit with two heat pumps and they cut our electric costs almost in half!

If like me, you have a house that is laid out oddly (built in multiple stages and it is a split level) they offer an easily retrofitting alternative. I even plan to use one on our 24' enclosed trailer that we are modifying to be an overnight camper (we use it to tow the 4 door Can Am Maverick X3 Turbo). In fact, the RV industry is starting to install mini Splits in higher end 5th wheels. If our 5th wheel was laid out in such a way that I could retrofit it, I would! For sure our new workshop will have a couple of Mini Splits!!


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## CWWoodworking (Nov 28, 2017)

I didn't really notice the electric bill go up when I ran air in shop. I have one of those hotel heater/air conditioning. But I have excellent insulation.

For a 2 car garage, and a few hours here and there for a hobby, I'd guess the electric would be practically nothing. If the insulation is good.


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## BurlyBob (Mar 13, 2012)

Heat is a bigger concern for me. The ac will only get used for maybe 2 months, tops. Heat on the other had maybe 4-6 months. There's a stretch in Jan/Feb where it can get so cold I can never get the garage warm enough to work in there. When it's below zero and the concrete floor gets cold it's almost impossible to heat it sufficiently to work out there.


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## ibewjon (Oct 2, 2010)

With my mini, the lowest heat temp I can set it to is 60. Keeping it at that temp with the mini is still cheaper than using the 4 kw resistance heat to keep it at 50. So the floor never gets cold, and I can turn it up ahead via phone app. It's a win / win for me.


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## tvrgeek (Nov 19, 2013)

Both myself and two Mitsubishi authorized service suppliers will disagree. The evaporator runs only about one degree below the dew point, so very poor de-humidification. Older low SER units, 14 or so, the coil ran around 45 to 47 degrees and they worked fine. These super 18 variable speed compressor jobs run more like 53 to 55 degrees. I target 50%. @ 72 degrees. On super hot days, it probably does a better job, but we have a lot of the year here where it is not very hot but humid, so it has a low cooling load. I had a SEER 18 window unit in my small shop in Maryland and the same problem. OK in August, but soggy spring and fall.

Natural gas is almost way cheaper, but of course, you need a furnace and that has to be amortized. Propane is usually by far the most expensive heat source. It can be worse than resistive!



> Mini splits do de humidity if properly sized. And it may cost less to run the heat pump than your gas heat, depending on your electric and gas rates. If you use propane, most likely cheaper to use the mini split heat pump. Just keep the filter clean. Way more efficient than a window unit. If you have an actual gas furnace, not just a gas heater, you may be able to add ac to that. I am pleased with the operation and cost of my mini here in Illinois, an hour south of Chicago.
> 
> - ibewjon


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## ibewjon (Oct 2, 2010)

I have not checked my coil temp because the humidity stays low. I have a 27 seer LG.


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## Lazyman (Aug 8, 2014)

I turned on and measured the coil temperature of my mini split at 27° F (20 seer) so I think that the Mitsubishi guys just told you something to get you off the phone or didn't want to deal with a warranty repair. I would get an independent tech out out to look at your unit-maybe someone who is not a Mitsubishi service supplier. Warranty service is like insurance: Deny the first, second and third time and they will likely stop asking. You have to be relentless. I have found that if you ask them to spell their name, they tend to listen better.


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## Lazyman (Aug 8, 2014)

Bob, I have found that simply getting one of those foam floor mats to stand on while out in the shop helps a lot on those really cold days.


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## Idahoan (Sep 4, 2020)

Try Alpine Home Air for outstanding hardware and support that floored me. I had never installed a system before, but bought the hardware from them. They walked me through every question I had. They knew their stuff and never blew smoke up my kilt. When I was done, I had my friend in HVAC come over to verify my work. He said I had done 11/10 work and was super impressed with the hardware. Now he is trying to get one of his suppliers to the hardware, which is Gree. Alpine's hardware is manufactured by Gree which they re-label 'Blueridge' for their house brand. I am almost certain they sell units and systems that are cool only (no heat).


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## Knockonit (Nov 5, 2017)

I've been using alpine home ac for years, have it in my shop, dual head 2.5 ton heat pump, works great, and does awesome on taking humidity out of shop, regardless of what some say, in fact i didn't get drain right on install and it backed up and caused one of the coils to freeze up, fixed now, but can bring my 1k sq shop down to 78 degrees from about 95 in a couple hours, i have two monster ceiling fans that i turn on once room cooled ,helps maintain air movement. 
mini split only way to go, only issue imo is filtering, i put two filter dust units in, and am presently assembling a pre filter system to put over heads to keep out the little dust mites, lol
good luck, be the best investment one can make. 
rj in az


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## Woodmaster1 (Apr 26, 2011)

Free 10000 btu window unit easy install cools my 30x33 just fine.


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## gbarnas (Sep 25, 2021)

For those of you with a DIY Mini-Split in a 2-car garage - where did you install it? 

My least-dusty space is the back of the concrete block chimney in the center of the inside wall.I'm thinking of securing a pair of 1x4s horizontally with 2x4's vertically (about 18" high) with a plywood face. Mount the internal unit there so the lineset exits the back, goes up and across the ceiling and out the opposite exterior wall. Debating whether to go up into the attic or across the ceiling in 3" PVC to protect the lines.

There's a gas fireplace on the house side of the chimney, but I'd be securing my unit such that it did not pierce the flue or the blocks themselves - securing into the concrete block webs. 

The outside wall is my miter saw station and oscillating sander - the two largest dust producers, so trying to avoid that location if possible.

I have the Mr Cool 18K unit, roughly 450 s/f shop space. Will be used for both heat in winter and cooling in summer. Garage has 2" foam-board insulation and good weather seal on the door. Fully insulated attic.
Thanks for your thoughts!


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## Lazyman (Aug 8, 2014)

There really isn't a dust free place in my shop to put my mini-split so it is simply as close as possible to where the outside unit is. That also positions it so that the cool or warm air is easy to directed towards where I usually stand when working at my workbenches. My dustiest tools are my CNC and Lathe which are coincidentally about as far from it as possible and my Wen air cleaner also happens to blow its filtered air directly towards the intake. I recently wrote a quick journal about how I added an air filter to the intake of my Mr Cool. I will update after some time passes with results. I also recently stumbled upon a series of videos about making a DIY Corsi-Rosenthal box fan air filter that may actually be more effective than the Wen and even higher end cleaners It will certainly be cheaper than the high end ones. I am planning to try to making one that I can hang from the ceiling of my shop using this approach because floor space is at a premium.


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