Product review (3 stars): Think twice before using one of these!
I've been using one for a few years because I was too lazy to get into a crawl space to vent the dryer properly. These do collect lint but they do nothing about the hot moist air as the other two by-products of the drying process. It gets pretty cold here during the desert winters and that warm air was always appreciated... until we saw the damage. Our windows would fog over, especially upstairs as the air drifted up, and when it cooled there was water that ran down onto the sills. That water, as well as the moisture on the walls, led to some mold and drywall damage that was difficult to repair. Some sills began to rot and had to be replaced. No, we don't do a lot of drying for the two of us but the cumulative effects don't take too long to manifest themselves. If you don't clean the lint trap regularly it quickly develops into a rotten smelling black bilge like substance that is very hard to clean... and did I say it reeks if you let it go a week or two. We have an electric dryer so fumes were never an issue. I just did the deed and drilled some 4" holes, ducted the dryer down to the crawlspace and then out to the great outdoors. Having that trap sitting on the floor next to the dryer also caused my floor tiles to loosen as the heat slowly broke down the glue that held the tiles in place. I wish I had ducted the dryer the day I bought it. If, on the other hand, you have no choice then go for it but be forewarned that it can cause physical damage and perhaps even health issues because there's no way this little box can handle all the lint that passes through, and over, it. My mistake for even trying it! I went with 3 stars because of what using it can cause but if you have no other options then you'll probably like it but I wouldn't do it again in any property I own.