When installing a whole home hepa filter, wouldn't it be more advisable to have the input supply to the hepa after the furnace filter to extend the filters life? I was think about this due to the fact that the large particals are for the most part removed by a MERV 8-10, 4' thick, furance air filter. It is a abatement branded Hepa system.

It seems like a good idea to me but are their any draw back or issue that can be created by setting it up in such a manner?

I am just planning a installing fpr a new personal system in a recently purchased foreclosure. I plan on removing the 2 year old Carrier VMA Oil Furnace and installing the new NG modulating Infinity system with Hybrid heat and Greenspeed heat pump (and new all alum Evap coil just to be safe. Over sized LL Filter driers. Also a new sealed duct system with ducted returns. I plan on making my return a minimum 48"x25" to reduce air velocity so that the Filter can caputre more particle so i can reduce my cleaning and dusting. BTW, most likely i will be installing two Carrier Infinity GAP filtering system. I'm going for extreme over kill. This is only my initial Plan!! What the hell i may as well also add a RFG REME Purifier while i'm at it. I did forget to mention the system will be zoned.

If you can think of anything else i should look into please let me know. I want to have the greatest system i can create. Also, its great to show customer your setup!!

I just need to seal the home a bit better and spray foam the roof deck and the basement walls or floor do you think.... It is a ranch home which i know is worst on energy consumption. If i could afford to pull the sheet rock down so i could have the exterior first floor walls sprayed i'd do!

Any info or comments on my plans are welcomed! Thanks!