Can I use my basement as an earthtube?
I am building a house in Zone 5, stick framing, 1.5″ exterior outsulation, 2×6 walls with a full basement. As it starts warming up (finally!) I can already sense the second floor is notably warmer than the first floor. Two basement stair openings are wide open, no doors, literally exuding a cool air that lingers in the first floor, almost making it feel like the AC is on. Entering the first floor from outside there is significant temp drop. I am attributing it to the well insulated home (caulked framing, caulked and taped XPS panel seams, caulked plywood seams) that retains the coolness of the basement. It’s still all open still, no sheetrock, no doors, and am thinking of “pumping” that cool free air from the basement into a duct system that brings it to the second floor. Kind of like an earthtube concept. I am in the process of designing my own ERV system, and not sure if I can (or should) marry the two ideas. Perhaps a system that draws air from the basement, rather than outside (tempered air, warmer in the winter, cooler in the summer). I have a small room off the main basement that can be sealed and isolated as a plenum of sorts. So outside air enters freely into the “plenum room” by a damper, where it is naturally pre-treated, again – warmer in the winter saving the ERV from getting hit with 5 degree air and cooler in summer where it may be 68 degrees rather than 80 – it is picked up by a 10″ duct and fed to the ERV in the attic which then distributes the air to the second floor. Will make sure that basement room has low radon levels (for what it is worth).
What do you think?
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