Product review (5 stars): Works Well
In order to make sure no lint got into the house, we added an extra, home-made filter onto the exhaust filter.  Now we are thrilled with the results.  Lots of heat into the house, and no lint or excess moisture.  Everyone's house is different, so the moisture level may be a problem for some.  We took a hosiery knee-high stocking, and cut off most of the sock portion.  The elasticized portion (part that holds the knee-high near the knee) is the perfect size for fitting around the product's filter.  We sewed shut the other (cut-off) end.  Now we scrape lint out of the stocking and the product filter once every few days, and have no problems - only lots of "free" heat.