be patient...
What a difference these little things make! In a small room you notice less smell within minutes, in a larger area it took days to start to smell a difference, but eventually it is smelling better in my basement and these things are the only difference.  They do make a noticeable high pitched noise, so I turn it off in my son's room at night - probably going to get him something else so I can leave it on 24/7.
Rating: 5 stars