Heating and A/C for new garage

[bill9860]

Been following this journal since I got the green light from the wife to obstruct her view and lose a couple of trees. Just about to sign contract w/ builder on new 26x28 (exterior) detached garage (3 car attached to house but need place for toys and to work...I mean play). Wall height at perimeter is 10 feet (so outside matches existing house/garage) rising to 12.5 ft in middle 15 feet or so to accommodate lift. Decided on gas heat (can run from house) so planning on the 45k btu Hot Dawg. It seems this should be sufficient. Garage will be 2x4 walls w/ R19 with R30 in unfinished attic. Interior square footage is about 670. Does volume come in to play with the high ceiling? Also, will have A/C through the wall. From what I read based on square footage 15k btu seems to be the ticket. But again, does the volume come into play because of the ceiling height necessitating something more in the 18k btu range? Any assistance is appreciated.

 

[Trailer Park Casanova]

Ya want 400 cu ft per min air flow for every 400 sq ft of space being conditioned.
Your ceiling height is ideal.
18K BTU should do it with the insulation you mention.

You may consider 2 slightly smaller units for those super hot, long Va summer days, and they will run on 115 v instead of 220V.
But having said that, make sure you have 220 to the garage anyway to run your welder.

COSTCO and sometimes Home Depot has the window units on sale.
They are a bargain compared to what they sold for just 5 years ago.

For a few years the cheap-o cheap-o DaeWoo's were the best performers blowing the most air and the coldest air.

Inspite of what the benchmark on the unit claims, they all differ from brand to brand.

So ya visit the in-store displays and see which brand offers the most bang for the buck.