First time not been but two weeks. But my concern is the whistle noise I notice on return. I purchased several and I will try the next one to see if it continues
I called to get a little advice and I must say they are so helpful and professional. They have a good price and ship very fast. I intend to shop here as long as I need filters.
I have used these filters for more than a year now and have been very happy with their performance. The cost is great when purchasing in quantities. With the Canadian smoke I feel my indoor air is cleaner.