"HL" wrote in message news:5Zfpd.1669$VL6.466@clgrps13...
If the temperature difference between the plenum and a duct is 8F (ie:
Plenum is at 120F duct at register is 112F) can this be translated into
duct
efficiency?


No.



Not that I can do much about it as all my ducts above a finished basement
ceiling just curious.