Review on Klimapartner RKI Backdraft Damper Inline by Yuan Walsh

I used these to replace a couple of standard mufflers (the kind with a thin sheet of paper-thick tin that pops and pops at the air duct opens every time the wind blows). Not only did the old flaps get in the way on windy days (which startled the family dog), they never closed fully, letting cold winter air into our home. Unlike older standard shocks, the shock does not flap or pop in the wind as it is a spring loaded shock that is held closed by a spring when air is not escaping. If you measure the diameter of the duct beforehand and the duct is in good condition, you should have no problems installing it. I love that the shutter damper includes two rubber grommets that eliminate the need for sealant. Simply remove the existing cap/cap from the vent, insert the damper blade into the duct, replace the cap/cap (minus the old damper) and you're done. That's all. I have three of these installed now, two on the tumble dryer exhaust vents and one on the bathroom exhaust duct. The simplest of the three fit easily, because the air duct was in perfect condition. The other channel was slightly deformed, requiring the use of a rubber mallet to gently hammer the damper into place, i.e. gently tapping alternately along the edges of the damper from 12 o'clock to 6 o'clock and beyond. 3 o'clock to 9 o'clock and so on (if you do this, be careful not to apply too much force to the sides of the bolt damper to avoid bending the damper body as this could pinch the bolt wings and prevent it from working). The only difficult installation of the three was not the fault of the louver, but the fault of the air duct in my house, which was poorly installed and compressed into an ovoid oval shape. The solution in this case required practicing my MacGyver craftsmanship with my own hands - I extended the air duct with sheet metal and sheet metal screws, fitted the muffler into a new appropriately sized duct extension, and then fabricated a new hood cover from sheet metal and Self-tapping metal screws to protect the outlet of the duct from rain and snow. The damper flap not only eliminates the popping and slamming of the old ones, but also protects against cold winter air, birds, rodents and those damn paper wasps that see every nook and cranny as a potential nest.