Not too big not too small mini split ?

[BTI]

I've been reading all the Mini-split discussions I can.
My question is this, My garage is 28x40 and 12' tall walls with open trusses.
4" of styro in walls and approx 2.25" of closed cell on ceiling, 2" under slab, no windows, 2 insulated roll ups, 1 insulated walk-in door.
I am heating with and electric boiler hydronically.
I would like to install a mini-split for a heat boost when there is someone else helping me and also dehu'n the air as well as some cooling.
Right now even with temps in the high 90's the building never gets over 80.
That said it IS humid inside!! I'm in Ohio, but feels like New Orleans right now LOL.
I did the calculations and most places are calculating for a house, they all recommend approx 24k btu.
I'm afraid if I go with this much it will hardly ever kick on and dehu the place.
I also don't need it to be 72 degrees in the place, just 77 and dehu'd would be fine.
Building is shut up most of the time, doors may open but they are shut quickly.

I'm thinking more along the lines of a 12K or 18K at most.

What you all think???

BTI

 

[sneezer41]

If you intended to run it all the time, I would agree with a smaller unit. Since you mainly plan to run it when you are working getting help etc, use a larger unit. Get an inverter unit and it can tune itself down when it not needed, and yet have the punch to quickly bring the temp down

 

[BTI]

In the summer I will never turn it off....I'll just set it to 77 and leave it.
In the winter the hydronic will keep it at 50 in there all teh time, then if I have "help" I will bump it to 65 or 70 so they don't get cold.
Max time running at the 65-70 will be 5 hrs, then it will be shut off until the need arises.

BTI

 

[paris_tj]

Some, my china made 24k mini split has a dehumidify setting on it. My shop is 30x40x10 and it does a nice job.
But I do run a standalone, $179(Frigidaire) 70 pint dehumidifier that does most of that work, and man does it make a difference.