Mini Split Size

[bluegoose972]

My shop is 30'x35'x12' wall red iron metal building on a concrete slab. I'm in Central Texas and can expect consistent mid 90'-100 degree temperatures during the summer. The shop had two 10'x10' roll up doors that are not insulated. There are 4 ea 3'x4' windows with two facing west.

I'm having 2" of closed cell foam shot on the inside walls and ceiling. I chose a white roof to minimize absorbed heat, but the walls are red.

The shop will only be used in the evenings and on the weekends for wood working and some automotive. Not planning on keeping it cool all the time and just looking to take the edge off during the peak times.

Have installed an exhaust fan to quickly evacuate the heat in the gables. And will have two ceiling fans to help with air movement.

Looking at a Mr Cool DIY setup. Will the 24,000 btu system be large enough for my setup? Would I be better off downsizing and installing two 18,000 btu units on opposite sides of the shop? Looked at the 36,000 btu unit, but concerned that it will be really cool in an isolated location and warm everywhere else.

Any help would be appreciated.

 

[Jackfre]

I don’t know how the building will behave with your insulation and sunlight. Of the three proposed options the two 18’s would be the best, for load conditions, redundancy, air circulation and efficiency. I would suggest the wireless control option for you as you can start things up remotely and have the space conditioned when you arrive. All of the larger mshp’s I am aware of in the 18 and up sizes have 4-way air sweeps. I would position the evaporators kitty corner about 1/4 of the way from the corner.

 

[dcg9381]

Goose, I'm just a little south of you. I have a 40x60x16 building. 3-4" of open cell foam.
I have 3 14x14 doors (roll up) that are basically crappy R5 or so. Sealing around them isn't great.

My roof is galvalum (reflective), building is a tan color, and I have no direct sunlight on any of the ends.


I have no exhaust fans. No ceiling fans currently.

I'm running 2 x 24K BTU Daikin units. I can cool into the 70s when it is hot out, but he units run 100%. My shop has a "living" type area where I concentrate both HVAC units, but the entire building gets cool. A circulation setup would help if I needed cooler air on the opposite ends of the building.

My usage - nights and weekends is largely the same as yours (for now).

 

[bluegoose972]

Goose, I'm just a little south of you. I have a 40x60x16 building. 3-4" of open cell foam.
I have 3 14x14 doors (roll up) that are basically crappy R5 or so. Sealing around them isn't great.

My roof is galvalum (reflective), building is a tan color, and I have no direct sunlight on any of the ends.


I have no exhaust fans. No ceiling fans currently.

I'm running 2 x 24K BTU Daikin units. I can cool into the 70s when it is hot out, but he units run 100%. My shop has a "living" type area where I concentrate both HVAC units, but the entire building gets cool. A circulation setup would help if I needed cooler air on the opposite ends of the building.

My usage - nights and weekends is largely the same as yours (for now).

Great information. Thinking I will start off with the single 24k btu unit and then I can either add another smaller unit or a window unit if not getting enough cooling.