Ground-Coupled Cooling & Earth Contact — FarmPal
Below 6-8 ft depth, soil temperature holds steady at the annual mean air temperature (50-65°F in most US locations). Earth-sheltered walls and earth-tube ventilation tap this free cooling reservoir. Slab-on-grade with insulation skirt: insulate the perimeter (not underside) to couple the slab to deep-soil temperature while preventing edge losses. Earth-bermed walls: 3-4 ft of earth against the wall provides R-equivalent of R-15+ and stabilizes wall temperature near soil temp. Combined with night ventilation, ground-coupled mass keeps peak indoor temps 15-25°F below peak outdoor temps. Critical detail: vapor barriers on the earth-contact side prevent moisture migration into the building while allowing thermal coupling.
Below 6-8 ft depth, soil temperature holds steady at the annual mean air temperature (50-65°F in most US locations). Earth-sheltered walls and earth-tube ventilation tap this free cooling reservoir. Slab-on-grade with insulation skirt: insulate the perimeter (not underside) to couple the slab to deep-soil temperature while preventing edge losses. Earth-bermed walls: 3-4 ft of earth against the wall provides R-equivalent of R-15+ and stabilizes wall temperature near soil temp. Combined with night ventilation, ground-coupled mass keeps peak indoor temps 15-25°F below peak outdoor temps. Critical detail: vapor barriers on the earth-contact side prevent moisture migration into the building while allowing thermal coupling.