I own a commercial building (5000 sq ft) and have 5 rooftop package units ranging from 2 tons to 3 tons. My tenant (a bank) has just completed a buildout of the interior and their HVAC engineer specified 13 returns (24" x 24" inlays) that do not accommodate filters. Historically, the filters were always located in the returns inside the space. Hence we have no filters in place now.
The engineer's specification seems rather odd to me since every retail property I have seen has filters on the inside. My primary concern (the tenant is responsible for HVAC maintenance) is the foot traffic on the roof and the potential for water leaks. I sent my HVAC on the roof to install filters until this issue is resolved and we have already had one leak caused by the improper replacement of a panel on one unit.
Other than reducing traffic on the rood is there any other compelling reason to have five filters on the roof or thirteen filters in the interior. The first thing that comes to mind is the frequency of filter changes, which would obviously be more frequent with 5 filters versus 13.
Any other thoughts?