Supply duct too small?

Duct was plastic, cut as shown. All registers on first floor are like this (smaller than opening). One year warranty inspection. Slab foundation.


Thanks in advance.

vent 2-400.jpg

Perhaps the system was balanced to function that way? Not enough information to say, really, unless you took some face velocity measurements.

What the hell have they used for duct?? that looks like green plastic sewer piping.

Thats never right, it’s not even insulated



Since they were all that way, I would agree that it’s probably to balance the system. Looking at those cuts, it would have been much easier to make a big ole cut than a little one;-)

I’m definitely not a HVAC guy but would you insulate a duct that’s in concrete? I don’t know how they do it:-k

sorry missed the slab bit!