# Thinking about installing DIY ductless split unit ac/heater in my shop,what are the pros and cons?



## a1Jim (Aug 9, 2008)

Hi friends,
Just wondering if anyone on LJs has installed a ductless split unit in their shop or if any HVAC folks have input about the idea of my idea of installing this kind of unit in my shop?
My shop is 28x32 with 14' tall ceilings and I live in southern Oregon where we have a pretty moderate climate even though summers can reach 100 degrees and winters around freezing both of these temperatures are more of an exception rather than long-term constants. More typical are temperatures 70-80 degrees in summer and 50 - low 40s in the winter.
Thanks for your feedback.
Jim


----------



## Knockonit (Nov 5, 2017)

gotta be dozen or two conversations about this in the last couple months, try searching, yeah i know site is really hard to maneuver , and yeah its the only wayt to go, although some additional IMO filtering is required, even with a awesome dust collection system, 
good luck 
rj in az


----------



## wapakfred (Jul 29, 2011)

Go for it, I'll be putting one in my shop this next year (I hope). Pros are operating cost, cons may be filter changes required from recirculating the dust. I have heat in the shop, but my AC is a window unit that's expensive to run and frankly doesn't do that good a job. I see the mini split as offering some heat but better AC (in my case).


----------



## Ken90712 (Sep 2, 2009)

Research dust issue with filters.


----------



## CaptainKlutz (Apr 23, 2014)

+1 many threads exist on topic minisplit

Here is link to one I have bookmarked, as I shared my refrigerator dolly solution for a rental home.








HVAC in a garage woodshop


I took a few months off as I acquired some new tools including a used 220v delta unisaw, dust collection system, and a few other things. Now that I have my shop layout situated, I am running into a much different issue. Heat and humidity. I living in the Raleigh NC area and it gets kind of warm...




www.lumberjocks.com





IMHO - Since HVAC requirements vary dramatically by region, highly suggest you obtain some quotes from local HVAC contractors. They will help educate on proper sizing for your space, if additional insulation is required, and will share the equipment brands with local parts/service available. HVAC units are made/specified differently for hot/cold climates, especially when buying a heat pump unit. Getting this local education will make it much easier to buy a similar mini-split (likely made in China by Midea or Toshiba), and embark on the DIY path. 

Best Luck.


----------



## OzarkJim (8 mo ago)

I replaced my house central unit with Mini Splits and they do a great job. I plan on installing a couple in our shop once we get it insulated. 

You can install Mini Splits yourself if you have a few basic skills. It is not hard to do at all. I have found that most HVAC pros in our area hate the mini splits as they cut into their business models (installing expensive central units and duct work). 

Pro: 
Easy to DIY install
Very efficient operation
Can be setup in zones
No duct work (depending on design)

Con:
Can be expensive if you need multiple units (IE: for large house with a lot of rooms)
Not as effective at heating in extreme northern climates 
Hoses will need to be run thru walls and can be unsightly. 
Some indoor unit designs place large blower on an interior wall (perhaps unattractive and in the way in a house)
Possible filter clogging issue (can easily be resolved) and any forced air style unit will have this issue anyway.

You indicated 14' walls? Is your shop insulated? Can you lower ceiling or install blowers to circulate air? That is a lot of extra area vertically to heat and cool. I get it though, my sidewalls are 10' and the roof peak is about 16' or so. For that very reason, we plan to install sheetrock ceiling and insulate the attic!


----------



## LesB (Dec 21, 2008)

Jim,
The climate there is suitable for these heat exchange systems. Two big problems with them in a shop is the dust and second they function the best when they run 24/7 and maintain a limited range of high to low temps because they don't have the ability to make large adjustments quickly. If you let the shop go cold (or heat up) over night they can't catch up in the AM and will revert to electric resistant for heat (if the unit is set up for it) which blows all the money you saved. The cooling cycle will struggle to catch up. A good range to maintain would be about 5 to 6 degrees between high and lows on a 24 hours basis. If you are in the shop every day this may work for you or if you are watchful of weather changes and adjust the thermostat settings to match. 
If not I think a propane heat system would be better for heating because it can respond faster.


----------



## Jake229 (Jan 14, 2020)

Hello!
I wanted to install AC in my shop and opted for a Mr. Cool DIY mini split. If my memory serves me correctly, it is an 18K BTU unit. To be honest, I use it for AC in the summer and have an overhead furnace for heat in the winter. The mini split does produce heat down to 5 degrees, although isn't very efficient. The efficiency







rating for the AC component is stellar though. I hear that the newer versions are even better, although I don't know it for sure. I did add a small filter to the top of it and will make an external filter box, but it hasn't been on the top of my to do list, even after 2 years. I blow it out and wash the filters spring and fall, although I use my overhead furnace to heat my shop. My size is 24x32x11', similar to yours but not quite as tall. I added in a 60" ceiling fan which helps too. I do need to obtain an air scrubber, as my shop exclusively for woodworking. 

Good luck and let us know what you chose to do.
Jake


----------



## OzarkJim (8 mo ago)

LesB said:


> Jim,
> The climate there is suitable for these heat exchange systems. Two big problems with them in a shop is the dust and second they function the best when they run 24/7 and maintain a limited range of high to low temps because they don't have the ability to make large adjustments quickly. If you let the shop go cold (or heat up) over night they can't catch up in the AM and will revert to electric resistant for heat (if the unit is set up for it) which blows all the money you saved. The cooling cycle will struggle to catch up. A good range to maintain would be about 5 to 6 degrees between high and lows on a 24 hours basis. If you are in the shop every day this may work for you or if you are watchful of weather changes and adjust the thermostat settings to match.
> If not I think a propane heat system would be better for heating because it can respond faster.


Les,
I agree. I don't live in that area but got the impression from the OP that the temps were moderate year round. Not that surprising with the prevailing winds off of the big Pacific heat sink. And as you say, that is ideal for mini splits. It's the folks with snow piled 10' high that won't get much benefit in the winter from them (at least that is what I have heard). 

We get more varied weather here in North Arkansas but typically our extremes don't last very long either direction. I don't plan to install heat strips (electrical resistance) variety of mini splits for the exact reason you cite. But my take on winter heating is to use the mini splits to just barely keep shop above freezing at night and then use propane to heat it up quick if and when we go to work. We often only work an hour or two in the shop and sometimes not at all as we have a lot of other chores with 20 acres to maintain. 

Jake,
I like the setup in your shop. We are looking at using roofing tin (red) on the upper 2' of our walls as well but sheetrock on the ceiling with insulation above that. I know it is a side bar conversation but how did the cost of the tin vs sheet rock work out?


----------



## Steinbierz (Jan 9, 2018)

I have been thinking about putting a mini-split in my steel building shop to supplement the central HVAC...I need to do some more work on my insulation though. I have spray foam but have a lot of big gaps around my garage doors and I have three single-pane windows that I need to replace.


----------



## OzarkJim (8 mo ago)

Steinbierz said:


> I have been thinking about putting a mini-split in my steel building shop to supplement the central HVAC...I need to do some more work on my insulation though. I have spray foam but have a lot of big gaps around my garage doors and I have three single-pane windows that I need to replace.


Another side note: We lived several years on Bolivar and used to race go karts at Alvin!


----------



## difalkner (Mar 11, 2013)

We're in NW Louisiana where the humidity is often in the 90% range, summer temps can easily get to 105° and winter temps down in the high teens, both often at that humidity range. Our shop is out two-car attached fully insulated garage and we have a 12,000 Btu Gree mini-split with heat/cool capacity - works great! It's a high SEER unit at 22 and uses less energy than my wife's hair dryer. It keeps the shop cool in the summer with humidity in the 35% range and warm in the winter with humidity around 30%, sometimes 35%. I can't recommend them enough.


----------



## OzarkJim (8 mo ago)

difalkner said:


> We're in NW Louisiana where the humidity is often in the 90% range, summer temps can easily get to 105° and winter temps down in the high teens, both often at that humidity range. Our shop is out two-car attached fully insulated garage and we have a 12,000 Btu Gree mini-split with heat/cool capacity - works great! It's a high SEER unit at 22 and uses less energy than my wife's hair dryer. It keeps the shop cool in the summer with humidity in the 35% range and warm in the winter with humidity around 30%, sometimes 35%. I can't recommend them enough.


Shreveport?

I was hatched in El Dorado, AR.


----------



## Lazyman (Aug 8, 2014)

Another recommendation for getting a mini split. I installed a MrCool DIY last summer right around the beginning of the 100+ temperatures streak here in DFW. I set it to come on every morning around 9am and within an hour it was comfortable in the shop. As I a test, I cranked it down to its lowest setting and it pretty quickly got the temperature down into the 60s even though it was over 100° outside and my garage shop if very poorly insulated. I went with an 18k BTU unit which I think is considered 1.5 ton for my 20x20x9' shop. In cooler environment or with better insulation I probably would have gone with a 12k BTU unit. 

I recently blogged about my setup and adding a filter to reduce fine dust from getting inside the unit. It is too early to evaluate how effective my filter setup is but so far there is literally no dust inside. 









Journal - Mini Split Air Filter


I installed a minisplit and will document my experiences with using it in my Shop




www.lumberjocks.com


----------



## KentInOttawa (Jun 25, 2013)

I have a 20x24 foot shop with good insulation and relatively high ceilings (8-12 feet) with a Mitsubishi 12K BTU mini-split. In January, the unit will have been installed for two years. My shop is an almost exclusively unplugged shop, although I will run a lunchbox planer now and again with the garage door open, I make sure to turn off the minisplit until the dust has settled somewhat. I also have a ceiling mounted (noisy) filter to help with the heavy load moments such as when using the planer and for a couple of hours afterwards. I use the shop almost daily and the planer every few months, and I clean the filters every couple of months. I do notice the dirt on the filters when I am cleaning them but it is not matted at all.








First and foremost, that extra ceiling height is going to wreak havoc with almost every bit of auto-magic software that is installed to make the unit more comfortable and efficient. All of the automatic modes will adjust the fan speed based on percieved requirements but will not compensate for the high ceilings.

As an example, when in heating mode, the unit will dump heat into the room but the fan will not be enough to keep the air from stratifying, so the warm air will rise and the cool air will drop. My system would stop heating when the air at 10-11 feet high (the unit's height) reached the set temp (20 C or about 68 F). The trouble is that the air at people height (5-6 feet) would drop to about 10 C (50 F). Turning the temperature up did not warm up the lower levels. Running the fan 24/7 at high and setting the vane direction for a wide spread helped, but that worked against a lot of the claimed efficiency.

Similarly, in cooling mode, the fans are insufficient to keep the air mixed with that much ceiling height. That means that no cool air gets up to the unit to tell it to stop cooling, so it just keeps dumping cool air 24/7 regardless of the temperature below. I had mine set for 25 C (about 75-80 F) and it was still cooling at full capacity when I manually intervened (shut it off) when the temperature below was at 14 C (58 F) and dropping in late June!

I wound up using some house fans 24/7 just to destratisfy the air enough that most (not all) of the stratification went away. I've since replaced the house fans with a centrally-located, 54" industrial fan. I run it 24/7 in the reverse (updraft) mode to fight stratification and can now set my unit on quiet mode and leave it alone for the season. It took quite a bit of research to find a quiet fan that could move a lot of air in the slowest speed setting AND that could also reverse. By using the updraft (reverse) mode, the unit gets a more realistic temperature of air to read and I do not get a draft. It is also very quiet. The lack of draft is important when heating to the bare minimum in the winter.

Beware of all the "remote thermostats" that are marketed for these units. They are not really thermostats at all, but just a remote controll with a temperature reading (and probably humidity) to display. Just because the remote "thermostat" is at 5-6 feet off the floor, your minisplit will probably still be using the temperature at the indoor unit (at height) to determine whether to run or not. It is extremely frustrating trying to figure out why there is a 10 C (18 F) spread between the set temperature and the actual temperature and your unit still not turning on to produce more heat. DAMHIKT. My remote is still powered on ONLY because it displays the relative humidity.

With my ceiling fan, I am now happy with my set up. It is quiet and efficient combination. I just wish that I didn't need to climb up the ladder to clean the filters every few months.


----------



## a1Jim (Aug 9, 2008)

Thanks, guys for your input, I'll try searching the topic again.


CaptainKlutz said:


> +1 many threads exist on topic minisplit
> 
> Here is link to one I have bookmarked, as I shared my refrigerator dolly solution for a rental home.
> 
> ...


Good Ideas,thanks


----------



## CaptainKlutz (Apr 23, 2014)

LesB said:


> they function the best when they run 24/7 and maintain a limited range of high to low temps because they don't have the ability to make large adjustments quickly


 My experience with a mini-split in AZ contradicts this statement? 
My unit can change shop temp +/- 25° in less than 2hours, usually less than 90min. I keep unit turned off unless plan to work in garage. Heat pump raised a 48° shop to 72° in about 50 min last week. It routinely drops the July/Aug 88-90° overnight low to 75° in ~45min in morning. 
Have 18K mini-split in ~22x28x11 garage with zero insulation in the walls and ceiling, and 2" of foam insulation in a steel garage door. The biggest challenge is lack of insulation. Summer time heat load with 110° high, makes unit unable to remove over 30° difference; even with AC running 24/7. Despite lack of insulation, when outside is 32° on a Jan morning, mini-split heat pump has no issue maintaining 65°+ for project finishes to cure overnight.

Ambient humidity plays a key role in system performance and efficiency. Lower humidity requires less ave BTU cooling to change air temp, where higher humidity requires more ave BTU. Hence my results may not repeatable in another climate, and is another reason to consult with HVAC expert in your local area.


----------



## Lazyman (Aug 8, 2014)

I haven't found that I need to run mine 24/7 either. I can easily turn it on when the temperature in the shop is 90° and get it down into the mid 70s and drop the the RH within an hour. With a high ceiling, it might be a good idea to have some fans running to help keep the air mixed up.


----------



## difalkner (Mar 11, 2013)

OzarkJim said:


> Shreveport?
> 
> I was hatched in El Dorado, AR.


Better. Bossier City. I only go to Shrevesville when I absolutely have to.


----------



## difalkner (Mar 11, 2013)

Lazyman said:


> I haven't found that I need to run mine 24/7 either.


I run ours 24/7 all year. But we also keep the door open to the house so when I'm not working in the shop it's like another 400 sq. ft. room that's part of the house. We walk in/out of the shop all day long and since it's so well insulated it really feels like the rest of the house.


----------



## a1Jim (Aug 9, 2008)

KentInOttawa said:


> I have a 20x24 foot shop with good insulation and relatively high ceilings (8-12 feet) with a Mitsubishi 12K BTU mini-split. In January, the unit will have been installed for two years. My shop is an almost exclusively unplugged shop, although I will run a lunchbox planer now and again with the garage door open, I make sure to turn off the minisplit until the dust has settled somewhat. I also have a ceiling mounted (noisy) filter to help with the heavy load moments such as when using the planer and for a couple of hours afterwards. I use the shop almost daily and the planer every few months, and I clean the filters every couple of months. I do notice the dirt on the filters when I am cleaning them but it is not matted at all.
> View attachment 3861785
> 
> First and foremost, that extra ceiling height is going to wreak havoc with almost every bit of auto-magic software that is installed to make the unit more comfortable and efficient. All of the automatic modes will adjust the fan speed based on percieved requirements but will not compensate for the high ceilings.
> ...


----------



## a1Jim (Aug 9, 2008)

Thanks for that great information Kent ,very helpful ,this makes me think I'm just better off replacing my heater and not to go the split unit route.


----------



## OzarkJim (8 mo ago)

a1Jim said:


> Thanks for that great information Kent ,very helpful ,this makes me think I'm just better off replacing my heater and not to go the split unit route.


I firmly believe you are still better off with the Mini splits. The issues that Kent mentioned can be addressed.

First get a GOOD circulation fan. Something large enough to really circulate the air in a significant manner.

Second, as Kent mentioned, most MS units come with remotes that functions as the thermostat (they have what is called a "follow me" function). You can also mount the indoor blower lower on the wall such that the heat isn't sent straight to the ceiling (try placing the circulation fan mentioned above close to the unit as well). 

Third, do something about your tall ceiling if possible (can you install a dropped ceiling (this will help with any type of system).

Fourth, if you have a decent dust collection system it is unlikely that the filter clogging issue will be that significant. If it is, you probably should be running a separate filtration system for fine dust anyway as that is a sure sign you need one. Again this would be an issue with any type of system. If you run a lot of machines like we do, dust and dust control is just part of the game.


----------



## KentInOttawa (Jun 25, 2013)

OzarkJim said:


> I firmly believe you are still better off with the Mini splits. The issues that Kent mentioned can be addressed.
> 
> First get a GOOD circulation fan. Something large enough to really circulate the air in a significant manner.
> 
> ...


I agree (mostly). *I'm happy with my system now that I have the ceiling fan installed and now that I no longer expect the actual temperature to be precisely what I have set it for*. Similar issues would arise if a different heating system attempted to use software to be friendlier or "smarter". Any old school heating or cooling system will suffer similar stratification problems unless it has a true remote thermostat with a sensor at people height that actually controlled the heat production. They will probably also be noisier and less efficient than a mini-split. Given that a mini-split will give both heating and cooling from one unit, they are the clear choice for me. FWIW, I can expect and do see temperatures here of -30 to +35 C (-22 to +95 F).
Here's a different view (from my PC in the shop) showing the layout better. (The garage door is to the left, hidden behind the tool cabinet). The green box on the opposite wall is the air filter; it's noisy but effective. I have that mounted to blow air from the front (left-side here) of the shop back to the minisplit at the rear. It is left turned off unless I feel the need for the filtration such as sucking away the fumes from the dirty bench below it or when running dusty machinery.








I spend most days in my shop; it keeps SWMBO much happier when I'm out from underfoot. I spend a lot of time surfing from this workstation when I cannot work because of my TBI (that is more often than I am able to work 🤕 ). I keep the temperature somewhat cool in the winter (usually 18 C-ish ~65) and warm in the summer (24-26 C ~75-80 F) and dress appropriately.
It has taken me a while to refine the settings to work well for me, so I do not use the follow-me function. It has never been able to find or follow me with that to the far corner of the shop where the PC is located. Here is what I have set now, with the ceiling fan blowing upwards (not blowing up ) on its lowest speed. This makes for a relatively draft-free and even temperature throughout the shop.








I have it set to stop heating or cooling just after supper and to resume whatever it was set for at 07:00 the next morning. The shop is always close to its set temp by the time I get out there (08:00-09:00). The actual temperature will only vary a degree or two throughout the day.


----------



## a1Jim (Aug 9, 2008)

KentInOttawa said:


> I agree (mostly). *I'm happy with my system now that I have the ceiling fan installed and now that I no longer expect the actual temperature to be precisely what I have set it for*. Similar issues would arise if a different heating system attempted to use software to be friendlier or "smarter". Any old school heating or cooling system will suffer similar stratification problems unless it has a true remote thermostat with a sensor at people height that actually controlled the heat production. They will probably also be noisier and less efficient than a mini-split. Given that a mini-split will give both heating and cooling from one unit, they are the clear choice for me. FWIW, I can expect and do see temperatures here of -30 to +35 C (-22 to +95 F).
> Here's a different view (from my PC in the shop) showing the layout better. (The garage door is to the left, hidden behind the tool cabinet). The green box on the opposite wall is the air filter; it's noisy but effective. I have that mounted to blow air from the front (left-side here) of the shop back to the minisplit at the rear. It is left turned off unless I feel the need for the filtration such as sucking away the fumes from the dirty bench below it or when running dusty machinery.
> View attachment 3861852
> 
> ...


Thanks for your info. nice shop.


----------



## OzarkJim (8 mo ago)

Nice shop Ken.

I just didn't want anyone running from mini splits based on issues that can be addressed.


----------



## a1Jim (Aug 9, 2008)

OzarkJim said:


> Nice shop Ken.
> 
> I just didn't want anyone running from mini splits based on issues that can be addressed.


I decided on a heater for a number of reasons not just what you said.


----------



## HorizontalMike (Jun 3, 2010)

Hi Jim,



OzarkJim said:


> I firmly believe you are still better off with the Mini splits. The issues that Kent mentioned can be addressed.
> BINGO - First get a GOOD circulation fan. Something large enough to really circulate the air in a significant manner.
> 
> MITSUBISHI IS PROGRAMMABLE AND HAS REMOTE - Second, as Kent mentioned, most MS units come with remotes that functions as the thermostat (they have what is called a "follow me" function). You can also mount the indoor blower lower on the wall such that the heat isn't sent straight to the ceiling (try placing the circulation fan mentioned above close to the unit as well).
> ...


ALL of the above Jim. I finally got my MS in 2017 here in South Texas! Before that, I could not work in the shop without sweating big drops onto all my cast iron machines! MY FIRST UPGRADES :
1. Added Thein centrifugal filter to my HF DC.
2. Eventually built two high efficiency air filters with 5 micro-filters (both have 2-speeds and set to complete circular rotation). I used old squirrel cage fans from replacing Furnace/AC system systems.
3.Also have several floor/carpet fans (squirrel cage) when needed.






























BTW, I have never had an issue with over-loading the MS filters. I mounted my MS up high, with less than 1-foot line between outdoor and indoor units for max efficiency. My Air-filtration boxes picks it all up.  ALSO, my air filtration boxes actually clean the air so well that you know it within ~2min or less, because your nose quits itching from the "escaped" DC dust.... 👍


----------



## HorizontalMike (Jun 3, 2010)

HorizontalMike said:


> Hi Jim,
> 
> 
> 
> ...


The filters are FPR 10, 7, 5, and 2, in that order. In other words FPR 10 is the last filter to actually filter the air. Honestly the FPR 10 rarely needs replacing.


----------



## thompsonscooling (2 mo ago)

a1Jim said:


> Hi friends,
> Just wondering if anyone on LJs has installed a ductless split unit in their shop or if any HVAC folks have input about the idea of my idea of installing this kind of unit in my shop?
> My shop is 28x32 with 14' tall ceilings and I live in southern Oregon where we have a pretty moderate climate even though summers can reach 100 degrees and winters around freezing both of these temperatures are more of an exception rather than long-term constants. More typical are temperatures 70-80 degrees in summer and 50 - low 40s in the winter.
> Thanks for your feedback.
> Jim


Good morning. As a fellow woodworker and as an HVAC contractor I would recommend a 2 ton mini split AC and Heat Pump 17 -19 SEER system that can run anywhere from $3,900 -$4,900 depending on who installs it. I would not recommend buying online and installing yourself because it can be a nightmare waiting to happen. There are several installation points that, if not adhered to, will lead to premature failure - if you get it running at all. This is not to impugn your skill level or intelligence or even tenacity to achieve a certain result. It is just FYI. There are some good contractors out there in your area who would do a great job at a reasonable price. It could be cheaper or even more expensive that I estimated. You would need to have a 20 amp 2-pole 230 VAC circuit wherever the outdoor unit is set. And the indoor unit is powered from the outdoor unit. Also the indoor unit will have to drain condensate to the outside somewhere - depending on your local municipal codes. And be sure to mount the indoor unit as far from wood dust as possible. And you would probably be cleaning the filter weekly dependent upon how much cutting, sanding ect. you are doing. I saw this post because I am interested in getting started in CNC routing and trying to learn as much as possible before I take the plunge. I hope this helps. Good luck to you and happy woodworking!


----------



## ClayandNancy (Feb 22, 2010)

a1Jim said:


> Hi friends,
> Just wondering if anyone on LJs has installed a ductless split unit in their shop or if any HVAC folks have input about the idea of my idea of installing this kind of unit in my shop?
> My shop is 28x32 with 14' tall ceilings and I live in southern Oregon where we have a pretty moderate climate even though summers can reach 100 degrees and winters around freezing both of these temperatures are more of an exception rather than long-term constants. More typical are temperatures 70-80 degrees in summer and 50 - low 40s in the winter.
> Thanks for your feedback.
> Jim


I just put a Mr. cool mini split in my shop. My shop is 14 x 36 with a 12 foot ceiling so far it is working great I have it set at 65° and it keeps it nice and warm in there. I haven’t had a chance to use it during the summer, but did have it on cool to see how it works and it was pretty chilly in there very easy to install and I am loving every minute of it.


----------



## a1Jim (Aug 9, 2008)

Jake229 said:


> View attachment 3861776
> 
> Hello!
> I wanted to install AC in my shop and opted for a Mr. Cool DIY mini split. If my memory serves me correctly, it is an 18K BTU unit. To be honest, I use it for AC in the summer and have an overhead furnace for heat in the winter. The mini split does produce heat down to 5 degrees, although isn't very efficient. The efficiency
> ...


Thanks for sharing how well it worked for you,nice shop.


----------



## jay1 (Feb 24, 2009)

a1Jim said:


> Hi friends,
> Just wondering if anyone on LJs has installed a ductless split unit in their shop or if any HVAC folks have input about the idea of my idea of installing this kind of unit in my shop?
> My shop is 28x32 with 14' tall ceilings and I live in southern Oregon where we have a pretty moderate climate even though summers can reach 100 degrees and winters around freezing both of these temperatures are more of an exception rather than long-term constants. More typical are temperatures 70-80 degrees in summer and 50 - low 40s in the winter.
> Thanks for your feedback.
> Jim


I have had a mini-split in my 24x30x9 shop in GA for 4 years now. So the cooling requirement is greater than the heating requirement. The shop is a separate structure on our lot. Choice was between the mini-split or the typical through the wall “motel” type unit. The mini was slightly more expensive is much more energy efficient. This unit has no trouble keeping the shop comfortable year round. My HVAC guy said to start off cleaning the filters every 2 weeks until I saw what the life was. Clean them using my shop vac with the brush attachment Now takes me about 10-15 minutes once per month. I am a bit of a fanatic about dust control, so I have a hanging air filter as well as dust collection for machines and sanding. 
I highly recommend the mini-split


----------



## woodworksbyjohn (Jan 11, 2011)

wapakfred said:


> Go for it, I'll be putting one in my shop this next year (I hope). Pros are operating cost, cons may be filter changes required from recirculating the dust. I have heat in the shop, but my AC is a window unit that's expensive to run and frankly doesn't do that good a job. I see the mini split as offering some heat but better AC (in my case).


I had a unit in Phoenix, no dust fiilters in them to speak of and they are so "technicallly advanced" darn near impossible to repair. Did all the maintenance x2 for keeping clean. Finally it was determined there is a slight leak so choice was to either re-fill unit yearly @ $200.+ or spend thousands to locate and it was still under warranty!! Sold the house, shop, and never ending problems.


----------



## dbray45 (Oct 19, 2010)

I have one, filters are worthless. Need to clean fan regularly.


----------



## OzarkJim (8 mo ago)

thompsonscooling said:


> Good morning. As a fellow woodworker and as an HVAC contractor I would recommend a 2 ton mini split AC and Heat Pump 17 -19 SEER system that can run anywhere from $3,900 -$4,900 depending on who installs it. I would not recommend buying online and installing yourself because it can be a nightmare waiting to happen. There are several installation points that, if not adhered to, will lead to premature failure - if you get it running at all. This is not to impugn your skill level or intelligence or even tenacity to achieve a certain result. It is just FYI. There are some good contractors out there in your area who would do a great job at a reasonable price. It could be cheaper or even more expensive that I estimated. You would need to have a 20 amp 2-pole 230 VAC circuit wherever the outdoor unit is set. And the indoor unit is powered from the outdoor unit. Also the indoor unit will have to drain condensate to the outside somewhere - depending on your local municipal codes. And be sure to mount the indoor unit as far from wood dust as possible. And you would probably be cleaning the filter weekly dependent upon how much cutting, sanding ect. you are doing. I saw this post because I am interested in getting started in CNC routing and trying to learn as much as possible before I take the plunge. I hope this helps. Good luck to you and happy woodworking!


Respectfully, I disagree. The Mini Splits are EASY to install. No need for professional to install. And I don't think they cost quite that much. But for sure compared compared to a conventional ducted central unit they are far easier to install and less expensive


----------



## difalkner (Mar 11, 2013)

OzarkJim said:


> No need for professional to install


I had a professional install our Gree unit because that's the only way to get the full 7 year warranty (maybe 8, don't recall). It's the high SEER unit and was $3k installed, not too bad.


----------



## jay1 (Feb 24, 2009)

Recommend installation of a hanging air filter for your lungs sake as well as the solution to stratification. If you look closely you will see that most of the smaller units are made by the same Chinese manufacturer. When on sale very reasonable prices. I have the smallest Grizzly units which do a good job. If you choose to use these smaller units, shop around on the Internet for replacement filters. Seems that these are all made by the same folks and the price varies x2 depending on the seller. 
Looking at the external filters I am surprised by how much much dust they catch. On advice of an IH guy I turn


KentInOttawa said:


> I have a 20x24 foot shop with good insulation and relatively high ceilings (8-12 feet) with a Mitsubishi 12K BTU mini-split. In January, the unit will have been installed for two years. My shop is an almost exclusively unplugged shop, although I will run a lunchbox planer now and again with the garage door open, I make sure to turn off the minisplit until the dust has settled somewhat. I also have a ceiling mounted (noisy) filter to help with the heavy load moments such as when using the planer and for a couple of hours afterwards. I use the shop almost daily and the planer every few months, and I clean the filters every couple of months. I do notice the dirt on the filters when I am cleaning them but it is not matted at all.
> View attachment 3861785
> 
> First and foremost, that extra ceiling height is going to wreak havoc with almost every bit of auto-magic software that is installed to make the unit more comfortable and efficient. All of the automatic modes will adjust the fan speed based on percieved requirements but will not compensate for the high ceilings.
> ...


A way to “kill 2 birds with 1 unit”. Look at installing 1+ of the hanging air filters. Varying sizes but 2 small work better than one large. The small one offered by Grizzly is actually the exact same unit offered by others. Although I have very good dust collection for all my generators, including sanding I am surprised how much dust appears, particularly on the larger external filter. Also if you should acquire 1+ of this model shop around for replacement filters. It appears that these are all made in one Chinese factory also to the same dimension and filtration specs. Pricing varies x2 for the exact same units.


----------



## DaveS2 (10 mo ago)

a1Jim said:


> Hi friends,
> Just wondering if anyone on LJs has installed a ductless split unit in their shop or if any HVAC folks have input about the idea of my idea of installing this kind of unit in my shop?
> My shop is 28x32 with 14' tall ceilings and I live in southern Oregon where we have a pretty moderate climate even though summers can reach 100 degrees and winters around freezing both of these temperatures are more of an exception rather than long-term constants. More typical are temperatures 70-80 degrees in summer and 50 - low 40s in the winter.
> Thanks for your feedback.
> Jim


Hi Jim,
I live in Canton GA and my shop is 25x26. Summers as you can imagine are hot (80-90) and the humidity can be high (65-80%). Winters are mild ( 40-50) with a few really cold days. I have my mini split installed 18 months ago and I am a really happy camper. Its a Trane and does an excellent job. I use the various features it has for keeping the shop always comfortable for the season. I run mine 24/7 and have had no problems with it. Keep the filter clean and all will be well.

I think you will be very happy with it. And running it is a pretty inexpensive proposition. Running mine 24/7, I added about $13 a month to my utility bill. Installation was about $3100 for a Trane/Mitsubishi 12,000 btu mini split with a 10 year warranty.

Enjoy
Dave


----------



## difalkner (Mar 11, 2013)

DaveS2 said:


> And running it is a pretty inexpensive proposition. Running mine 24/7, I added about $13 a month to my utility bill.


Interestingly enough, our bill went down when we added the mini-split. I think it's because we insulated the garage/shop and then began controlling the environment in there. It's on the west side of the house and because we leave the door open to the shop we now have two units cooling the house but this high SEER unit now takes the load of the larger whole-house unit so it doesn't run as much. And the mini-split unit is closer to the kitchen than the main unit so it feels better in there now, as well.


----------



## KentInOttawa (Jun 25, 2013)

jay1 said:


> Recommend installation of a hanging air filter for your lungs sake as well as the solution to stratification. If you look closely you will see that most of the smaller units are made by the same Chinese manufacturer. When on sale very reasonable prices. I have the smallest Grizzly units which do a good job. If you choose to use these smaller units, shop around on the Internet for replacement filters. Seems that these are all made by the same folks and the price varies x2 depending on the seller.
> Looking at the external filters I am surprised by how much much dust they catch. On advice of an IH guy I turn
> 
> A way to “kill 2 birds with 1 unit”. Look at installing 1+ of the hanging air filters. Varying sizes but 2 small work better than one large. The small one offered by Grizzly is actually the exact same unit offered by others. Although I have very good dust collection for all my generators, including sanding I am surprised how much dust appears, particularly on the larger external filter. Also if you should acquire 1+ of this model shop around for replacement filters. It appears that these are all made in one Chinese factory also to the same dimension and filtration specs. Pricing varies x2 for the exact same units.


Do you mean something like the miserably loud green unit high on the wall? If you read back, you'll discover that I only use it when doing grungy stuff at the greasy bench or when running the lunchbox planer. It is just too damned loud to be left running in an unplugged workshop. The ceiling fan is almost silent, uses less power and moves more air. Since I rarely use the planer, I don't get much airborne dust at all.








Here's a few months worth of accumulated dust.








I have no need for anything better.


----------



## woodchuckerNJ (Dec 4, 2013)

OzarkJim said:


> Respectfully, I disagree. The Mini Splits are EASY to install. No need for professional to install. And I don't think they cost quite that much. But for sure compared compared to a conventional ducted central unit they are far easier to install and less expensive


I agree, my son and I installed a Mr. Cool at his house, extremely easy.


----------



## BlueNo2 (Mar 20, 2014)

One other thought: have you considered the type of in-wall AC/Heater unit that used to be common in most motel rooms. Clearly noisier than a split ( but drop dead quiet compared to a router at full blow!), but I understand they are significantly cheaper too.


----------



## difalkner (Mar 11, 2013)

BlueNo2 said:


> I understand they are significantly cheaper too


And not nearly as efficient, not high SEER rating at all.


----------



## OzarkJim (8 mo ago)

BlueNo2 said:


> One other thought: have you considered the type of in-wall AC/Heater unit that used to be common in most motel rooms. Clearly noisier than a split ( but drop dead quiet compared to a router at full blow!), but I understand they are significantly cheaper too.


I actually looked into those at one time. Thing I didn't like about them is you had to cut a big hole in wall for installation and they took up valuable interior wall space. I like the way a mini split indoor unit can be mounted above cabinet height and the fact the unit only needs a 3" hole thru the wall for the hoses. In fact, that gives the mini split an advantage over a window unit too.

Initial cost isn't much less than the mini splits and as someone else mentioned they are less efficient so long-term operating costs will overcome the initial savings.


----------



## CaptainKlutz (Apr 23, 2014)

If you local weather is regularly below freezing for months at time, then typical recommendation is a mini-split system needs secondary heating system for lowest HVAC costs; 

Which is the advantage to the "Hotel" style HVAC unit over a mini-split. Most "hotel" units have option for emergency electric heating element, used when it is too cold for heat pump operation. 
Note - This does not help efficiency or lower total HVAC costs, but will keep you warmer in winter compared to heat pump. 

Hotel units are historically mounted near floor, for single reason that the are mostly intended to heat/recirculate cold air from floor. Which is what you want when heating is most important feature of your HVAC. When cooling is most important, mounting the unit higher on wall is more efficient; hence a common high wall mounting for min-split.

HVAC is always a compromise, and the dearth of variables will quickly make your head spin. Another reason to ask an local expert, and discuss ALL the options.


----------



## TheDane (May 15, 2008)

I have both a mini-split and a gas heater in my shop. The mini-split does a great job of heating/cooling for 8 months of the year here in Wisconsin, but the coldest months (December thru March) I need the Hot Dawg heater to keep the shop warm. During the warmer months, the mini-split runs continuously and maintains the temperature in the shop at around 65 to 75 degrees. When the outside temperature drops into the teens and below (last night it got down to 13 degrees), I shut the mini-split off and set the gas at 55 degrees ... doesn't take long to warm it up in the morning to 65. So depending on your locale, the mini-split may or may not do the job.


----------



## wapakfred (Jul 29, 2011)

TheDane said:


> I have both a mini-split and a gas heater in my shop. The mini-split does a great job of heating/cooling for 8 months of the year here in Wisconsin, but the coldest months (December thru March) I need the Hot Dawg heater to keep the shop warm. During the warmer months, the mini-split runs continuously and maintains the temperature in the shop at around 65 to 75 degrees. When the outside temperature drops into the teens and below (last night it got down to 13 degrees), I shut the mini-split off and set the gas at 55 degrees ... doesn't take long to warm it up in the morning to 65. So depending on your locale, the mini-split may or may not do the job.


That's more or less the situation I expect to have once I get one, though my winter is likely a month or so shorter than yours. I'm thinking I'll have to go to gas heat from maybe mid Dec. to mid Feb.


----------



## OzarkJim (8 mo ago)

I expect that I will have to use gas heat a little even here in North Arkansas. Maybe for two months of the year Jan-Feb. No big deal having both systems. Still beats the cost of a central system both in initial/installation and operation. And none of it will require an HVAC pro to install.


----------



## dbray45 (Oct 19, 2010)

Here is my opinion. I have a 20'x20' garage. I live in Florida and before I put the mini split in, the garage got to 120- 140 (F) in the summer. I insolated the ceiling and walls with rock wool bats that were great insulation and sound deadening material and insulated the overhead door. I put in a 1 ton unit and it works great. $3,200 and I put it in. If I choose, I can keep the garage at 68 degrees all year long - but that is stupid.

Keep in mind that I installed it myself and maintain the warranty myself. I have a master HVAC license and for 400 sqft, 12,000 BTU should be more than enough if you insulate properly. My townhouse in Maryland had a 1 1/2 ton heat pump and your garage shop should not need more that that - but you to have to insulate or spend the money in electricity, your choice. The one time cost of insulation is far better than the continued cost of power. I also have an exhaust fan and air filter installed in the ceiling. As a note, I had this quoted by a couple of contractor, I am retired and really want to stay that way. The two contractors told me that I need a 4 ton unit for the garage. I am guessing that they were sizing it based upon no insolation and with that in mind, they were not wrong.

Merry Christmas


----------

