Originally Posted By: meangreen01
To the above- how much you spend depends on what you feel like spending. Kinda like motor oil. If you're concerned about indoor air quality or want to reduce allergens then a $15-$20 filter might be worth it to you. I personally buy the cheapest PLEATED filter out there, I think they're TrueBlue or something. A buck or two a piece. That's about as cheap as I recommend going, since the only thing cheaper are the spun fiberglass types, which really do nothing except protect the equipment from larger chunks of debris.
I use the same ones (well, True Blue brand, Basic MERV 7's). Our HVAC guy recommends using anything but the spun glass filters, especially on high-efficiency furnaces (secondary heat exchangers). I don't run them 3 months though, usually change at a month. Pick them up on sale for about $1.60/piece at Menards.
That Filtrete looks Nasty! I don't think I could have let it go that long. Wonder what the air-flow losses are like with it that loaded?