Sizing of mini split for my garage

[nicobkn]

Hi guys,

I've been shopping around for a mini split with a heat pump for my garage. I've been getting mixed suggestions from various local installers.

My garage dimensions are 25x35 with 11' ceilings. R60 blown cellulose in the ceiling, r19 pink insulation in the walls, two r16 8'x8' garage doors and one service door.

The unis heat up to -4f ( I live in canada).

Some guys recommend 12btu and some 18btu. The difference between the two is very slim, around $200 or so.

Do we have any hvac experts on the forum ? My auxiliary heating (in case it gets below -4) will be two ceiling heaters (9600 watts total)

Thank you!



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[Donzi camino]

I am 22x35 and went 24 and it does fine. Not as insulated as you, so guess an 18 would do you right. I think the 12 is not enough, and for a $200 saving it would be a bad choice.

 

[vavet]

I have a 24x32 x 12. I installed a 18k Mr Cool unit last fall. I haven't used it through a hot sticky summer yet, but it has been great so far.
Your winters will certainly be more severe than mine, but you're also much better insulated. I also know I'm not trying to keep my garage as closely controlled as my house. I'm pretty happy if I can keep it below 80 in the summer and above 60 in the winter.

 

[duluthUPLAND]

I just purchased this 24k unit from Senville for my garage. I can't tell you how well it performs as the garage is just getting finished up.

I bought it direct from Senville on ebay for a great price. When compared to the smaller units the savings weren't significant to the point I felt like risking it so I over sized the unit for my 576 sq foot grarage.

My building is 24x24 and I just had it spray foamed, 3" on ceiling and 2.5" on the walls.

I'll have way more cooling power than I need but hoping that heating capability is ample. I'm northern MN and will have very cold winter temps. I don't know that the mini will be enough to heat it but I'm hopeful. These are rated to produce heat down to -22 F.

 

[justinjoyal]

I told you man !

12k if you want better dehumidification.

18k for quicker recovery and more heat.

Btw, your walls are R24.5 total.

 

[SouthLake]

I have a 6 year old Mitsubishi Mr. Slim (M-series) 18,000 BTU (in NJ), in a 650sq ft space. Concrete on grade, insulated walls, ceiling and door. I find that its adequate for the space but it does allow humidity to increase sometimes seasonally upwards of 50%-60%, which is uncomfortable.

I'll add, (knock on wood) the unit runs 365 24/7 and has been totally trouble free. It can be 68 degrees in there when its 95 outside, or 70 when its in the teens.