question regarding whole house air cleaners (example..april aire space guard) . Do these have to install right next to the air handler? Mine is in the attic, so I didnt know if these things will survive attic temps of Texas. Where my 20x25x1 return is in the hall ceiling, besides the frame, there is another maybe 6" or 7" of recess before the flex return starts. Can I use this space for installing some sort of whole house air cleaner? I know it depends on the unit used and some mods may have to be done. I just wanted to know if anyone has seen anything like this done before. This would be ideal so I wouldnt have to get in the attic to change filters etc... assuming these electronic filters can handle the extreme attic temp. Any suggestions? I was about to buy a couple of the Austin room air cleaners, but thought the whole house would be smarter since the Austin cleaner are some pricey little units.