I had bought the CIMR 2000 for my downstairs little over a month ago. I have a chronic cough from asthma and have indoor and outdoor allergies. I also watch my grand daughter who has indoor and outdoor allergies and she has eczema as well. I noticed that once I went to go to bed I started with coughing and needed to use my inhaler. I ended up buying CIMR 500 to put in my bedroom. Since I put this in my room I no longer have my cough at night. Also, both these units have helped myself with almost not needing my medicine for my allergies and asthma. My grand daughter does not have a running nose at my house and her eczema has settled down as well. Thank you Robert for making me and my grand daughter feel so much better..