Product review (5 stars): I don't know but works great!
Oh my gosh! I live in an apartment complex that has 21 pages of rules. An "installed" dryer is not allowed. This Haier along with a ProFlex Indoor Dryer Vent (You can find on Amazon) is just plug in and use; no installation. With no outside venting allowed, the combination works. No fluff floating around. Where does the heat go? I don't know but works great!