Workshop Heating & Cooling

My shop:

  • 20’6” x 20’6” with a 10’ heating and cooling (1)
  • All perimeter walls, except 12’ of one wall attached to my house, are not insulated.
  • Garage door is a regular 2 car garage door that I added insulation to. Two kits needed for my door. heating and cooling (2)shop heating and cooling (3)
  • Garage door has wide weatherstripping attached to the outside.
  • Ceiling above is not insulated.


My local climate:

  • I live in central Mississippi which is known to have a high annual precipitation level. audio-template.00_01_31_18.Still007
  • Mississippi also has a high average temperature. audio-template.00_01_37_05.Still008


Previous heating:

  • Two 1500w electric radiant heaters. They couldn’t keep up with the space. shop heating and cooling (6)
  • Two electric radiant heaters + a small propane Mr. Heater one plaque 4,000-9,000-BTU Indoor-Safe Portable Radiant Heater. This worked but didn’t burn as efficient as I had hoped and produced an odor that we could smell inside the house. shop heating and cooling (7)


Previous cooling:

  • Box fan. Even a steady breeze is still miserable in the high heat and humidity of the Southeast heating and cooling (8)


Current setup:

  • QuietSide brand mini split AC & heat pump unit. Model number QS18-VJ220
  • 18,000 BTU cooling and 19,800 BTU heating. shop heating and cooling (10)
  • Comfortably cools to low 70’s in the summer time and drastically reduces the humidity in the shop.
  • Comfortably heats the shop in the winter time. Although, the lowest setting is 61 degrees which is a little warm for working in the winter time. I’d prefer to work in a long sleeved shirt or light jacket in the winter and remove the long sleeves in the event that I get hot.
  • The outside unit is a lot quieter than the unit for my heating and cooling (11)


    • I frequently get asked questions in regards to how I heat and cool my shop. The point is to make a video covering all aspects of heating and cooling for my shop.

      • Why don’t you insulate your place. It would eliminate most of the need for heating and cooling. As well it becomes a much more comfortable space to be in. I live in Canada in an area where we range from minus 40 in winter to plus 100 in summer. In summer I don’t need any air conditioning and very minimal heating in winter. I have been very extreme with my insulating and weather stripping.

        • Every insulation company I’ve talked to said blowing insulation into the walls will settle in a few years and leave you with a foot or more of uninsulated wall. And I have horizontal bracing about halfway up the wall so every 16″ stud cavity would need two 3″ holes cut in and then patched. Just not something I want to do right now.

          • I know it’s a done deal for you at this point, but I thought I would add the following comment for other people considering options.
            I believe that with the mid height horizontal bracing, the settling would be much less than an entire column of insulation. If you are still concerned, could you have the insulation blown in and just use the flush plastic plugs to close the hole. They are made to be very unobtrusive. After all, it is a work area and most of the walls are obstructed by other things on the wall. Then if you think the insulation has settled after years, pop them open and add some more. I’m not saying that this would eliminate the need for a heater / air conditioner; just lessen the load requirements.

            Thank you Jay for all that you do for the woodworking community.

  1. Thanks for the explanation, Jay. I have considered one of those units for my garage/shop. Central TX gets blistering hot but not quite as humid.

  2. Jay,
    I follow you regularly and really enjoy your videos. I live north of you in Olive branch Mississippi which is right up at the top of the state. I was wondering if the company that did your install would also install in De Soto County. If you wouldn’t mind sharing the name of the company I would appreciate it.

    • I don’t remember off the top of my head what company it was so I’ll have to look up the receipt. But they were out of Alabama if I’m not mistaken.

  3. Have you thought about adding blow in insulation in the ceiling? Most home centers will loan you the blower.

  4. I was wondering if you knew if there was a minimum height to install that mini split.My shop, The Dungeon, as I like to call it, has very low ceiling space.

  5. I would like to see if this could keep my shop warm at a reasonable cost here in Upstate, NY. We recently installed a 135,000 btu propane wall furnace, but that thing is thirsty all the time, and we are only trying to maintain around 55 degrees. Our total garage space is around 24 x 72 with 12 foot ceilings but very well insulated. Cost of electricity scares me more than burning wood in a woodshop….lol

  6. My shop is 2400 square feet and very well insulated. My only heat is a barrel stove which never gets the shop above 50 degrees on the coldest days. I can’t see my breath in the winter, and I need to dress warm. For A/C, I installed two 13.5K BTU window units on my east wall. On 100 degree days they can keep it at 78 degrees. My next heat project is adding a second barrel on top of the existing one lined with copper coils circulating hot water to two radiators. PEX piping and accessories, pump, and two radiators with fans will run about $700. Since I have an endless supply of firewood it makes financial sense for my situation.

  7. I live in Northwestern Wisconsin. It was -1 this morning. I finally insulated all walls and attic, then added a Modine heater. Now it’s toasty warm in the winter. I am able to move WW equipment to the side so my wife can get her car in on those cold Wisconsin nights. In the summer, I just suffer with the heat.

  8. Thanks for all of the info. I have about 1000 sq ft with a 9′ ceiling. The shop that is fully insulated, in Maryland temps get crazy. This week we had record high 2 days and now it’s 29. Good to check out more than one dealer.

  9. Jay,

    Nice report.

    Question: I believe you said it removes the humidity in the summer time. I don’t see where it has an air handle/exchanger. Not being a HVAC guy, how does it do this? Where does the condensation go?

    I live in Tennessee and think it would work here. JimE

    • The cooling coils are on the inside. Air passes through them and condensation forms. It drips into a tray and is drained outside just like a forced air HVAC unit for your home.

  10. Just an alternative cooling option for those who don’t have the money for a mini split. I installed a 3’x6′ window in my garage wall, just so i could put in a 2 ton window unit (24k btu if i recall). GE made, picked it up from sams for under 450.00$. I live across the lake from New Orleans, in a worse zone as far as temps and humidity. Like Jay, also suffer from lack of insulation, and this unit can keep my 2 car garage in the mid 60’s in the middle of August, with the sun beating on the garage door all afternoon. I also did some cheap insulation to remedy that issue. I installed the window in case i moved, i could remove unit, or if it craps out and i get another, i dont have a hole in my house exterior that was cut to a non existing unit. Runs on 220, so not the amperage draw of a typical 110/120 vac window unit.

  11. I was concerned about dust stopping up the unit . I don’t have dust control for my shop and used to use a window unit, but with dust flying around I could not keep the filters clean . Do you have any suggestions for keeping the dust at bay, except for an obvious dust collector ? Thanks

  12. I buy the fancy filters in bull from depot when the mark them down to a super cheap price. I have the Wen air cleaner running, but really a couple cheap box fans and filters, same crap. At the unit i apply the expensive (clearance) filters outside the cheapo plastic guard, run some 2″ masking tape around seams, keeps the coils clean. And if you want to really hit the next level of penny pinching, remove filters, blow them out from the clean side outward. Or buy the washable filters, not sure if it will capture the tiny microns that will doom it eventually. And gotta have DC…

  13. Not sure if this was discussed, but I watched a Mike Holmes episode and they used a spray on foam insulation that could be applied through small holes in the wall. Not sure how easily this could be applied, but it may be an option for some folks that can’t get into their walls.

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