I have a Trane XV80 with downflow furnace filters. According to the Trane manual I am suppose to install 2 filters in a V position (as shown in the help file):
1) Do I need to do this? When I moved in to this house there was a single 16 X 20 X 1 filter laying across. I have been using a single filter for the past year (until I finally read the manual).
2) Are there any better filter systems I should use? The 16 X 20 X 1 filters seem very hooky. Even using 2 in the V seems clunky. Is it ok to buy a thicker filter say 16 X 20 X 2 or 4 and lay it across? Or will this mess up the furnace?
If the ductwork is already set up as you are now, you should be fine, just have to change the filter often.. Where the V it gives more surface area, and it lasts longer.
If you need better air filtering, then you can step up to 4" media, The media lasts about 6 months.