Stopping Air Leakage Through the Dryer Vent

In an earlier post, I introduced the issue of air leakage around dryer vents. So, I went from this:

To this:
I screwed it onto the base of the old vent and caulked around the interface. Like everything these days, it's made of plastic. So I painted it to match the house, and hopefully, to protect it from the sun's ultraviolet rays which will eventually breakdown may kinds of plastic. We'll see. In the meantime, the basic idea of this contraption is to prevent conditioned air from escaping the house. It works very much like an inverted-bucket steam strap , for those of you who are familiar with steam boiler systems. The lid comes off so you can clean the interior. Here's what is looks like with the dryer off:

...and with the dryer on:

As an operating issue, the device "sweats," because after all, it's expelling moist, humid air from the dryer. So it naturally wants to grow "fur" from dryer lint. Periodic cleaning will be necessary. Fortunately, the lid snaps on and off easily, and the bucket slips right out. It's a goofy-looking contraption, somehow reminiscent of a locomotive whistle, but hey, if it saves some energy, I'm all for it.