I have been using MERV 11 paper filters for several years with no issues. They work better than MERV 8. I change them at least every 6 months. If I had pets, I would change them more often. I don't agree with leaving a filter in the unit for a year, even though some filter manufacturers say it can be done. Also, I am always skeptical when a technician provides advice that doesn't seem to be based on any personal experience or research. Any filter will restrict air flow, especially when it gets dirty. That is just how it works. If the filter is very dirty when you replace it, you are not replacing it often enough.
|