Garage Workshop Build: Installing a Mini-Split Ductless Air-conditioner

by Patrick Harper - Blood, Sweat, and Sawdust

No more sweating profusely over expensive cast iron tools.  No more miserable summer days in the shop.  All thanks to my Mitsubishi mini-split ductless air-conditioner and the nice HVAC guys who turned up the system yesterday afternoon.


Ductless, split heat-pumps (also known as mini-splits) are the new standard in efficient heating and air.  These consist of an indoor unit (found in wall mount, flush-mount, and ceiling mount varieties) and an outdoor unit.  They are more expensive than tradition units, but pay for themselves with reduced energy costs.  Their benefits include, but are not limited to: reduced energy costs, less noise, and improved comfort.

If you’re thinking about getting one for your workshop, do the legwork yourself to offset some of the cost.  I installed my system for about half the cost a professional quoted.  I purchased my equipment from a reputable online seller and had professionals test, vacuum, and connect the lines.

Wall Bracket-web

The indoor unit mounts to a wall bracket.  I attached the wall bracket using five screws.  I secured two screws to studs, and the others into drywall anchors.  The wall bracket includes a guide that helps you locate the 3″ hole you will need to drill through your wall for the refrigerant lines.

Cooland Hole-web

Wall Sleeve-web

Once I had the bracket mounted, I carefully drilled my hole and installed a wall sleeve that came with my installation kit.  The hole should slope slightly downwards to make sure drainage from the condensate line.  Then, I passed the refrigerant and condensate lines through the hole and attached the indoor unit to the bracket.


Next, I installed a line hide kit on the outside of the house and connected all of my electrical wires.  The installation kit I purchased from the online retailer included both wires I needed.  One connects the outdoor unit to the disconnect box.  It uses water proof connections and supplies power to the entire system.  The other wire connects the outdoor unit to the indoor unit.  The terminals on both units are color coded and hard to mess up.  I also installed a surge protector to the disconnect for added security.


Disconnect Box and Surge Protector-web

I installed the outdoor unit on an equipment pad.  It’s made of hard plastic and does a good job of stabilizing the outdoor unit and absorbing some sound.

It took the HVAC professionals about an hour and a half to connect the refrigerant lines and turn up the system.  The system works flawlessly.  It’s so quiet, it’s hard to even tell when it’s running.

Mini-Split Ductless Air-conditioner

I purchased all of my equipment from  I am very happy with the service I’ve received from them so far, and highly recommend them.

For the rest of the workshop build, check out the garage workshop build index.