So far, hardly any difference between formerly-used Merv9 and these Merv11's. New filter has been in place since 7/1. HVAC system is 3 y.o.in this rental duplex. Ceiling fans are run constantly and cleaned regularlyand thoroughly. I'll reserve final judgement when 3 mos. change-out occurs.
The service excellent; however, the filters are too undersized to properly fit. 16" is actually 15 3/8". That leave a 1/2 inch gap allowing air to bypass the filter. That's just one side as an example. I measured the opening as 16x25x4, and that's what I ordered. Why send a filter with reduced dimensions?
Purchased two filters for our HVAC system. Received a few days after placing an order over land line. Fit was perfect. I will be making another order when the time comes.