I definitely wouldn't recommend anything smaller... Winter is finally upon us here in Pittsburgh, PA and I have been running this humidifier on high 24/7 in just a small 8' x 11' room. As we speak, the current humidity outside is 55% and this big humidifier is struggling to keep the humidity in my snake room at only 43%! I definitely have to be getting a new pump for the built in humidifier system on my furnace, because this humidifier isn't keeping up by itself...