AC For The Shop?
I have generally always thought that having AC in your garage/shop was overkill unless you were doing woodworking and needed to control humidity. My only memory of being hot working on stuff at my parent’s house was welding up my car trailer with long pants, a leather welding jacket, and leather welding gloves on on a 90 degree day. Living in Wisconsin of course I could have simply waited a day or two until it cooled down but I was stubborn that day. Once insulated, the garage at my old house was pretty nice all summer long so long as I didn’t open the garage door on hot days.
In the shop once the interior was finished and insulation blown into the attic I was very happy in the winter but found that that in the summer once the heat made its way in it was almost impossible to get it back out. I tried running box fans in the windows all night every night, tried opening garage doors with the lights off after dark, tried running the heater fan. But nothing seemed to even make a dent on cooling it off in there. My theory is that unlike my old house and my parent’s house i have almost no shade, so the heat comes in all day long and the insulation under the concrete prevents the heat from being able to dissipate into the ground the way it did in my former garage.
When originally planning the shop I estimated it would cost about $10,000 to have a full heat/ac HVAC system installed. As I said above I didn’t foresee a need for AC and I thought a normal shop heater would work just fine for heat. 2019 was my first summer with the shop fully insulated and we had a couple weeks where I flat out couldn’t work out there. During that time I started looking in to options for AC hoping to find something that would at least take the edge off for a fraction of the $10,000 I knew I’d be facing to do it right.
Ductless mini split systems immediately came to mind as I was happy enough with the shop heat I had and I thought I could just hang a unit on the inception shed wall and run the lines out the side wall to the condenser. I decided to get a bid for a system. The HVAC contractor advised me that a mini split would not work well in the shop but still agreed to write up a quote for it but also wrote one up to add a conventional AC system with some round ducting hanging from the ceiling. A 2.5 ton mini split would be $5,000 and a 2.5 ton conventional AC with ducting would be $7,000. I wasn’t surprised by the conventional system cost but got sticker shock for the mini split. I decided to table the idea.
Summer 2020 came and I decided to work through the heat but it was driving me crazy. I started looking into more options and found I could buy a 3 ton DIY mini split system for around $2,000. Keeping in mind that the HVAC contractors told me a mini split would not work well I thought for only ~$2,000 I would pick up the unit and hope that it could at least remove the humidity, and blow cool air on me if I pointed it at the shop bay. I placed the order and after hearing nothing for week I eventually found out due to covid supply chain issues I would not be getting it until fall at the earliest. I decided there was no point to do that so I cancelled the order and decided I’d do something in spring 2021.
As the snow was starting to melt I reached back out to the HVAC contractors with a new plan. See what it would cost to install the conventional system while also replacing the shop heater with a home style furnace. To my surprise after almost 2 years, and adding a furnace to the plan, the bid came back at $8,000. Sold!!!
Now I had to figure out how to get 240v power and an AC disconnect mounted outside on the back wall of the shop.
