Energy Efficient Air Damper by Luxury Metals

Energy efficient butterfly dampers keep cold air from coming back down vent ductwork.
Can be seen here: ( www.luxurymetals.com/butterfly... )

[@TS-zp7pe]

Could you motorize the blades so they could be used as light dimmers in solar tubes for daylight harvesting?

[@oshepard04]

what percent of ventilation does this permit???

[@seae2030]

Does it keep out the humidity as well?