Has anyone done a ductless mini split in a garage workshop? Need advice.

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  • Has anyone done a ductless mini split in a garage workshop? Need advice.

    So I haven't done a thing yet, but looking into it.

    As you know I am currently in a small 2 car garage that is a shared space. I am looking to no longer share that space and that is going to take some doing, starting with losing a Crepe Myrtle that is in the way in the back yard for a garden / tool shed.

    Anyway my old portable AC is honestly just not up to snuff, never really was. I could get it tolerable in the shop during the summer, but never comfortable. I am planning on finishing the insulation and closing off the ducts the portable used, and closing up that piece of wall between the doors.

    That leaves me with the issue of how to heat and air condition the space.

    I am considering a ductless mini split heat pump system. I have less than 400sq ft of shop space (396 to be specific), so it doesn't have to be huge. But small mini splits seem pretty rare.

    I am looking for ideas on what mini split systems are working well, any advice on doing the install, and how on earth can I hide the exterior unit from the HOA?

    If you have a recommendation for a specific unit that would be fantastic as well.
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  • #2
    I’m in the process of replacing my home split ac unit and talking to 4 different hvac co’s. The discussion comes up with all of them about my shop ac, which is a 24000 Amana heat pump window unit. I’m not 100% satisfied with its cooling ability and question them about mini splits. When it comes to price I become happier with my Amana, which at $1600. Is still less than half the cheapest quote for a 36000 btu mini split.


    • dbhost

      Editing a comment
      How big is your shop that you need that much cooling? My portable unit is 13.5K BTU, but the hoses literally pump heat right back into the shop before it can exit. I was thinking 18K BTU or smaller...

      If I wrap the hot hose with an old blanket, and use a box fan to boost the pitiful fan in the portable unit it does work well... It is just a LOT of fuss, and tries throwing itself apart way too often...

      Kind of thinking about the Cooper & Hunter 16K BTU https://amzn.to/3EVSzEB which is honestly way more cooling than 396sq / ft should need...

      I know being a garage, with those big doors, and leaky seals, even when new, I should go over the recommendations, but recommended capacity is 8712 BTU, In theory I could go with the 12K BTU model. https://amzn.to/3EwKo07

      I seriously doubt 16ft of connection line is going to be enough though. I am thinking at least 25' for lines and electrical. I will likely need the electrician to run a 220v outlet against a different wall, which means drywall patching. Ick...
      Last edited by dbhost; 11-23-2022, 02:09 PM.

  • #3
    We had ductless mini splits in our homes in Japan back in the early 90's in Toky,o Japan, and again from '92 - '04 in Osaka and '04-'10 in Toyota City. Loved the mini splits. Never had a problem with any of them.

    I convinced a church in their re-build in 2014 to go with the mini-split ductless. They were very hesitant but went with that. It was difficult finding someone to install it properly (the install was not difficult.) The church is extremely happy with the mini split - 2 inlets for the sanctuary, and another mini split (2 again) for the fellowship hall. Building design was modified so that 2 class rooms and 2 bathrooms were away from sun side. heating and cooling have not been an issue. They were happy with not having to have duct work installed.

    Currently we are building another church with similar design and will have ductless installed. They will need a 4 ton unit although the code guy says it will require a 5 ton unit and the need to re-wire with 8 gauge. He is wrong. the church will go with the 4 ton and 10 gauge wire.

    I learned something on codes on this one. State Codes can be one thing but if the MFG specs say something different and it has passed US certifications, the MFG code can override the State code. Specifically, The 4 ton unit says its maximum current draw is less than X amps, it can run totally (and start up) on 10 gauge wire without getting close to max draw, then 10 gauge can be used even though a states code requires 8 gauge for that size of a room and unit. I had 2 different licensed contractors verify this to me.

    Hank Lee

    Experience is what you get when you don't get what you wanted!


    • #4
      During my employment with the USMC in the public works dept they had literally 100s of mini splits to maintain. Every brand conceivable was there, and Mr Cool seemed to becthe favorite by everyone. I can’t remember ever having to replace one. The biggest problem I remember for any brand was draining the condensate. It was done by a tiny water pump via hose.


      • dbhost

        Editing a comment
        I have heard of Mr. Cool plenty, they are easily twice the price of the competiton. Are they that much better?