Choosing an Energy-Efficient Cold-Climate Wall Assembly
I’m entering the framing stage of a project to build a 24′ x 32′ garage with a roughly 10′ x 20′ mudroom on the garage level and a roughly 720 sq. ft. apartment above, with the stairs open below to the mudroom.
See attached floor plan drawings – very simple, open floor plan design. My goal is to achieve as high of energy efficient home as possible with a modest budget. I’d like to exceed code standards here in New Hampshire for R-value, but doubt I can afford the most energy efficient design. My main heating source will be a heat pump on the upper level with a back-up heating source of a pellet stove down in the mudroom. The structure will sit on a slab foundation and the slab will be insulated with rigid foam under the slab and I’m also planning to install radiant heat (exterior perimeter insulation already installed). Hot water will be a hybrid heat pump.
My carpenters are insisting on a 2’x6′ wall construction (foundation walls are 8 inches thick). At the moment, I’m leaning in the direction of the 2’x6′ wall construction with rigid foam insulation on the exterior to achieve an effective R-24 or higher with batt insulation in the wall cavities. I’ve read a lot of posts, but can’t quite make sense of it all, being new to all of this in general, both construction and energy efficiency. I’m grateful for the assistance I’ve received so far. It’s been helpful.
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