Thank you to Melissa and Alen Air Purifiers for providing such a great product and service to people like us. We have a 4300 sq ft, 40 year old farm house that has just about everything Alen can handle. Within 2 days of putting the 75i and 45i units into place we had the place smelling very, very fresh. My husband and I also felt much better with the clean air. The purifiers are so quiet that I keep walking past to make sure they are still on, and they are working away keeping our home environment healthy!