Re:Insulation: First the body, then the home (2011)
by nice__two on Tuesday January 31, 2023 @11:18AM
(#34597119)
It is much worse. The Berbel retains the insulation provided by the wall, when closed. This is nothing more than a fancy hole in the wall.
Opening and closing, means you get the best of both worlds.
[1] https://www.ventilatieshop.com/terugslagklep-in-ventilatieka...