I recently purchased a T4, and within a few days, the fan would not pull through the AC infinity filter if I had the pre filter on. They sent me a new fan determining that the first one was defective.
Needless to say, by the time the new fan arrived, the filter was clogged up from running for a week with no pre filter on. They then sent me a replacement filter.
2 weeks in on the new fan and new filter and everything was running great, until I noticed my temps going up. The new filter is somehow clogged, but the pre filter is clean as a whistle.
The room it runs in is a constant 70% humidity, so Im not sure if the humidity could be the problem or what?
I have decided to just let it go, trash the AC infinity filter and go with a Phresh or Can.
All in all, I feel the company has great customer service, but the quality of their filters is lacking. The fan will have to tell over time.