Damper options for the QA-4800, QA-5500, and QA-6500 whole house fans are:
Insulated R5 Gravity Backdraft Damper
Industrial grade gravity fed back draft damper requires no power and is standard with all CentricAir whole house fans. The R5 insulated gravity damper is designed keep attic air from entering the living space when the whole house fan is not in use.
Cold Climate Damper (Ceiling or Wall Mount)
Designed for cold climates, the Cold Climate Damper (available with CentricAir 2.7, 3.4, & 4.0 and QA-Deluxe 4800, 5500 and 6500 models only) is powered by a heavy-duty actuator that is tested to 60,000 cycles. The damper door is insulated to R-10, (upgradable to R-50), to help ensure an air tight seal whenever your whole house fan is not in use. The damper can be installed vertically or horizontally.
For regions of the country where it gets extremely cold, the damper door of the R-50 version is insulated with a combination of standard fibreglass insulation and VIP panel (vacuum insulation panel) to achieve its R-50 insulation rating.