The HVAC guy, who was from Crown Heating and Cooling, told me there should not be two filters in the house. He took that one out - it wasn't a half inch filter, or a one inch filter, but, get this... it was a five inch filter. With pleats. Apparently, pleated filters are bad. Especially five inch pleated filters. Of course I had to ask him why we were given one if they are so bad for the system. He said because without it, when you sit in that room, it's noisier when the system is running, because you can hear the air moving. Which is because more air is moving. So, basically, you are partly disabling your system with that giant, noise-blocking filter. Great! I wonder how much harder our unit worked this summer to keep us cool and how much extra we paid for it?
I'll be asking my PM about this, because there may have been a reason for the giant, five inch thick filter in the front room, right? Crown did install the system, after all. I'll keep you posted.
P.S. You might want to check that filter because we moved in our house in February, and our five in filter was lousy with filth. Really, really, really gross.