I had some issues with my old Alen purifiers but the customer service (thanks Tonea!) was fantastic. I was easily and quickly able to talk to a qualified person who could address all of my concerns. I traded my old ones and upgraded to newer bigger ones. The new ones were shipped and received within a week. I am so glad that I bought Alen purifiers. The new FLEX unit is very quiet and works really well. Very pleased. Thank you!!