"HL" wrote in message news:Xbrpd.3148$VL6.784@clgrps13...

"Steve@carolinabreezehvac" wrote
in message ...

"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.

Why?



Easy enough....what you ask, as you ask, translates to no.

Now, had you said, after a run time of XX minutes, with a duct run of XX
feet, with a heat rise of XXX degrees, and a delta of XX with a velocity of
XXX FPS can this translate to a duct efficiency...and the answer would have
been a possible yes.
There is a bit more info that would be needed as well, such as duct
construction, age, diameter.......

Otherwise,no.

8 degree loss on a run of say.....30 feet or less isnt enough to worry
about.
Depending on how long the run time was, your delta with be less or
greater...so...as you ask...no.