HVAC in garage shop?

[jamie]

It has been a while since I have posted...

I have a shop in my garage - about half of a three-car garage, also shared with a car and lots and lots of storage.

It isn't that often that I can actually do anything out there- it is way too hot in the summer, and barely bearable in the winter.

The shop is insulated on the walls- the walls shared with the house were already insulated and drywalled in, and I put in comparable insulation before I drywalled in the remainder. The garage doors are also insulated, as much as garage doors can be, at least. The area above the garage is partially insulated.

Has anyone here ever had a mini-split HVAC put in to their multi-purpose garage shop? Wondering how effective it is in the long run. I would only expect to run it when I was planning to be out there.

Also, does anyone have a ballpark as to what this would cost?

Thanks,

-jamie

 

[tri4sale]

I am having to replace my house HVAC so when I was getting quotes I asked for a mini-split quote for the garage. I got about 4 quotes and they all came in $3000 to $4000 for an oversized 1 car garage of about 320 sqft using a 1.5 ton unit. For your area you'll need a bigger unit since your's is larger.

Depending on how handy you are, it could be done cheaper I'm sure.

For now I just use a $400 portable unit, run it about an hour before I go out there, and a wall mounted barrell fan blowing on workstation area. Keeps me cool enough to work in the garage.

 

[jamie]

Wow that is pretty steep...

I have a fan in the window out there, maybe I will just deal with that!

 

[Mike Davis]

I would put a window unit in for $300-400 and be done with it.

 

[jamie]

Unfortunately that really isn't an option, it is in the front of the house and the HOA wouldn't like the eyesore. I also don't have really have room for a floor unit

 

[mquan01]

Unfortunately that really isn't an option, it is in the front of the house and the HOA wouldn't like the eyesore. I also don't have really have room for a floor unit

I had had the same issue and just planted some bushes around it

 

[redknife]

I have a mini-split. It works quite well and I would re-install in a heartbeat. Interestingly, we have a supplemental mini split in our finished basement and the filter gets dirty inside more quickly than the garage workshop. As far as "the long run" I expect it will last a long time (15 yrs?) although I can only vouch for the couple of years that its been running. The estimates above sound about right but I don't remember what ours cost. The process involves installing the outside unit with a 220v feed and running power and copper lines between the outside unit and the mini-split. You also need a condensate drain line from the inside unit to the outside world.

 

[tri4sale]

I have a mini-split. It works quite well and I would re-install in a heartbeat. Interestingly, we have a supplemental mini split in our finished basement and the filter gets dirty inside more quickly than the garage workshop. As far as "the long run" I expect it will last a long time (15 yrs?) although I can only vouch for the couple of years that its been running. The estimates above sound about right but I don't remember what ours cost. The process involves installing the outside unit with a 220v feed and running power and copper lines between the outside unit and the mini-split. You also need a condensate drain line from the inside unit to the outside world.

I've heard lots of good things about them. My goal is to put in a multi-room mini split for the garage and my sunroom to get year round use out of them.

 

[ehpoole]

Unfortunately that really isn't an option, it is in the front of the house and the HOA wouldn't like the eyesore. I also don't have really have room for a floor unit

If you have not already done so, you may wish to review your HOA agreement. Not all HOAs actually forbid such, it all depends on where they copied their agreement language from as there are several variations on the boilerplate agreements most builders use.

Our HOA has no language forbidding window units, so I have a 12,000BTU A/C (11,500BTU strip heating) window unit for my garage shop, ideally I would have opted for a 15,000BTU unit but they would not fit the existing windows without modification. I also have a smaller 8,000BTU window unit for supplemental cooling of my server room (which actually ran year round until recent hardware upgrades), but that unit is hidden from view. At 12,000BTU it is just barely able to cool the shop (about 525sq.ft. with 10.5ft ceilings) on a hot day if started about 12 hours beforehand and will fall behind on a hot day when the DC and larger power tools are in use for any length of time. That said, I am much more sensitive to temperature than most, so I typically need to cool the shop down to somewhere between 68-72F if I am to function out there for long due to my health and medications (I need the same temperature range in winter as well).

You will very much enjoy the addition of A/C and heat in your shop as such will greatly improve comfort. However, if you do not routinely run your A/C 24x7 then you will likely also want to add a dehumidifier to your list to keep your shop comfortable and control wood movement and equipment rusting (some units may include a dehumidification mode). If, like myself, you only run the A/C when you plan to be out in your shop then it will not have run long enough to bring down the humidity appreciably (which takes a few days to dry things out) and you will just end up with a cold and clammy shop where you shiver and sweat simultaneously due to the high humidity (which can be worse than no A/C). But with humidity control it will be quite comfortable and your equipment will cease to rust and wood will behave predictably from one day to the next (or even one season to the next). You will want to install a moderately oversized unit for your shop (but not excessively oversized) both to bring the temperature down within a few hours on demand and to account for the added heat load produced by your power tools (especially things like dust collectors and air compressors which generate considerable heat when operating) -- also, if your garage door faces the sun for much of the day then even a typical insulated door will still transfer a fair bit of heat into the shop while the sun is shining on it, adding to the daytime heat load.

That said, I am not terribly fond of the fact that banks force builders to impose HOAs on practically all new developments making it virtually impossible to avoid HOAs in many parts of the country unless one wants a real fixer-upper property. I have never understood why anyone would ever want to be so beholden to conformity and uniformity that there can be no room left for any sort of individuality in a community (how is such freedom?)?! I much prefer communities that have some character (and characters) and not just a sea of ugly square boxes all (too often) identical in size, shape, color, and landscaping.

 

[scsmith42]

I had a mini-split in a former garage shop. It worked well; as I recall I spent around $1,300 on the hardware and did the installation myself.

It was not good at cooling the entire shop quickly though, so my advice would be to keep it on a higher setting (such as 82 degrees) when you're not in the shop, and then turn down to 76 or so about an hour or so before you wanted to use the shop. Keeping it on the higher setting when you're not in the shop will also help keep the humidity levels down, and your equipment from rusting and your lumber from gaining MC%.

 

[jamie]

I had no idea that you could get a combo window a/c AND heat-- I will go find my HOA and comb through it.

Thanks!

 

[red]

I heat and cool my 800 SF basement workshop with a mini-split. It cost $3,000 to install in 2013 and worth every penny. I like a cool shop so I keep it at 68* during the summer months. It costs pennies a day to keep on 24/7. I am going to install one in my new shop once I get it built.

Red

 

[MarkE]

Our restrictive covenants state that a window air conditioning unit cannot be visible from any street. We had through-the-wall heat and a/c units installed on the back side of the building.

My shop on the first floor is ~570 sq/ft with a Fridgidaire FAM18HS2A, 18,500 btu a/c and 16,000 btu heat.
My Wife's shop upstairs is ~342 sq/ft with a Fridgidaire LRA12HZT2, 11,800 btu a/c and 11,000 btu heat.

The building is fully insulated (except under the floor/crawlspace), including insulation between the floors.

 

[junquecol]

Being a woodworker, you could build a tunnel in from window and set unit in so it can't be seen. You would have to build a co axle tunnel so inlet air (cool) doesn't mix with exhaust (hot). Think box inside box. Because unit exhausts moisture, I would use treated plywood, plus slope, and caulk bottom out past window sill.There were pictures of some on one of the forums a couple years back

 

[badger fan]

I had a Mitsubishi mini split installed in my garage work space last year. It was about$3,500 installed from what I recall. I would highly recommend it. My space is like a 2 1/2 car as an estimate. It cools and heats well. It has a dehumidifier as well.
i would highly recommend it.

 

[tri4sale]

I had a Mitsubishi mini split

That's the brand every HVAC company I asked for quotes uses, not sure why, googling mini-splits produces many companies, but all I got were quotes for Mitsubishi brand mini-splits

 

[Touchwood]

My shop is about 800 sq ft with 9.5 ft ceiling and well insulated. I installed a GE Zoneline heat pump (thru the wall motel type unit) about 25 years ago, when I built the shop. It ran continuously for 20 years. I replaced it 5 years ago with a newer model, but basically the same thing and it's doing the same job. http://products.geappliances.com/Ma...l/Dispatcher?RequestType=PDF&Name=20-S080.pdf.
I chose a model 6100 with 14800 BTU cool and 14000 BTU heat.(SEER of 12.5) .
It cost $950 installed..far cheaper than mini-splits.
I maintain the shop at 72 degrees year round (really) and supplement it with a small ($250) dehumidifier in July and August. I vacuum its filters about every 2 months. This one is also running continuously.
It means cutting a hole in the wall,but if you would plant shrubs to hide another type of unit it's the same deal. In my case I put the hole in when I built the shop.
I'm very happy with the performance, low noise and operating cost of this unit.

 

[mkepke]

I put a 'window' AC/heat unit through the wall of my shop several years ago. It's a pretty big unit (22K BTU?) for a 850 sq. ft. space, but I oversized it knowing that I would only run it intermittently - my shop is only insulated on the walls and the upper floor is completely uninsulated. It'll bring the temps down (or up) , but it won't take you to AC Nirvana.

FWIW, I looked at motel units: needed a BIG opening cut and put out too few BTUs. I looked at mini-splits - 4x the money. I looked at conventional systems - expensive and needed a service-closet created for the air-handler.

All that said, if we ever get around to finishing the upper floor, I'll take a close look at mini-splits again as prices have come down and multiple zones can be run off one outside compressor.

-Mark

 

[NOTW]

I recently had an HVAC guy come out to add some freon to my main unit and while he was there I asked him about cost for a mini split system for my one car garage shop. He suggested not doing a mini split but instead running two ducts off of the main house unit to the garage. I am planning to replace my units in the next year or so anyway so he said just up size the units 1/2 a ton when I do and add the extra ducting. So if your main unit is close to the bay you use and has the capacity you would be looking a few hundred dollars in ducting as opposed to $3k in a mini split.

 

[scsmith42]

I recently had an HVAC guy come out to add some freon to my main unit and while he was there I asked him about cost for a mini split system for my one car garage shop. He suggested not doing a mini split but instead running two ducts off of the main house unit to the garage. I am planning to replace my units in the next year or so anyway so he said just up size the units 1/2 a ton when I do and add the extra ducting. So if your main unit is close to the bay you use and has the capacity you would be looking a few hundred dollars in ducting as opposed to $3k in a mini split.

I would recommend against this primarily because in addition to ducts you will have to add in a return, which means that any odors, fumes, etc from the garage shop will be distributed through your house.

i would not want the smell of the finishing supplies, thinners, solvents, gasoline, and other shop chemicals to be spread through my house.