Thanks. I see that Alen has a smaller unit with equivalent sound ratings, less power consumption, and cheaper filters. It's still overly powerful for my small place, but the simplicity of their design is a good sign. BlueAir has a different suggestion for small spaces, with even lower sound levels than the Alen. It's still a while until mold/pollen season here (to say nothing of wildfire smoke from now on), so I have some time to explore.