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EERE » BTO » Building America » Solution Center Home » Image Gallery » Right - The butterfly damper of this crawlspace supply register opens when the HVAC fan is running; the damper duct is sealed with mastic and supported by strapping.

Right - The butterfly damper of this crawlspace supply register opens when the HVAC fan is running; the damper duct is sealed with mastic and supported by strapping.

Right - The butterfly damper of this crawlspace supply register opens when the HVAC fan is running; the damper duct is sealed with mastic and supported by strapping.