A 1,500-square-foot energy-efficient log cabin retreat for busy East Coast couple (and their two young sons) who were interested in building with “the smallest carbon-footprint possible,” With careful log joinery, a ground source heat pump and electric load handled by PV panels, the building’s total utilities have been averaging $38 per month. It was constructed using Rustic hand-peeled logs of fire-killed Montana Spruce are juxtaposed with smooth sanded Douglas Fir timbers, and our own hand-made doors and windows.