Garage mini split for heating?

[fteufert]

19 x 19 detached garage with 10 1/2 foot ceiling, northeast Pennsylvania

6 inches of ceiling insulation, 1/4" fanfold insulation, covered with OSB with sealed joints. 2x6 walls currently covered by OSB but no blown in insulation yet. Garager door is 16x7 insulated.

Gas line isn't an easy option (less than a foot down before I hit a ledge between garage and house which is 20 feet away)

I don't need 70 degrees in my garage, and one calculator put the heating requirement at 12,500 BTU's for a mini split heater.

is 10K, or 12.5K enough to get it to 55 or so when the outside temp is 10 or so? I would keep it heating all the time to say 40 or so.

Suggestions?

 

[ericm]

Keep in mind the minimum heating setting for the unit you may buy.
Also many minis have a lower heating BTUs than cooling BTUs.

 

[SALIV8]

You would have to look at the ratings for outside temps to see if the output matches your needs.

My next mini will be a gree saphire.

 

[LaneRover]

We did something similar for my in-laws apartment (above a garage on a rental property I have). They are gone from Christmas to May, we keep the apartment at 50 when they are gone using a mini-split system. Though it works hard when the temps are down in the single digits so far they are pleased with the cost of heating through the time they are gone. The big difference from what you say you have is that this place is fully up to code with insulation R-20ish in the walls and R-36 and R-49 (I think) in the ceiling. Apartment is 24x40. The lowest temp setting on the minisplit we use is 50. This is in coastal Maine

 

[Jackfre]

I would not go larger than a 12. You will need a unit that can heat down to -20*, so as pointed out make sure you have a clear understanding of the unit specs. Most of the 12's will operate down to about 3200 btu on heat.

 

[bmwpowere36m3]

Don't forget many units will output less at lower temps, ~60% output at 17* F. So a 18K unit, will only output 11K at 17*F.

However, some of the higher-seer/hyper heat units will produce more BTUs than "rated" BTUs at moderate temps and near "rated" at single digits.

 

[Rusty32]

I went a little big for my garage just to figure in the efficiency loss at low temps. Garage is 20 x 24 i went with a 24k btu innovair from ebay. I can get 70 in here no problem at -20 can cool down to 69 in no time at 95 degrees . I couldnt be more happy with this after 2 year

 

[fteufert]

Thank you for all the information and suggestions.

For one thing, if it is -20, I won't be using my garage!

I miss my coal stove from my old garage, and really wish I could bury a gas line to the garage.