[DKAudio]

What are the best price to performance furnace filters? I have been buying cheap fiberglass ones but what are your opinions? I know you should change the filter about every 3 months but my digital thermostat has a filter indicator, I assume it calculates how many hours the fan is turning and lets you know when the filter should be changed, should I go by this?

My furnace filter housing is pretty wide and it seems like 2 filters should go in together (it actually fits perfectly like that). I only put 1 filter in but why is the slot so wide? Also, the filter housing cap was missing when I bought the house, I have just been using masking tape to close it off everytime I replace the filter, is this acceptable?

Sorry for all the questions, thanks.