On Jan 24, 1:31*pm, "Ed Pawlowski" wrote:
"HVAC Guy" wrote in message

Your perception is entirely wrong. *Too much air flow can impede
performance rather then enhance it.

That's a function of the fan speed and blower size. *Generally the more
air you can push per unit time, the more efficient you can make the
system (increased ability to transfer heat from the exchanger or to the
AC coil).

But too much is no good either. *You need balance and there are curves on
the optimum residence time needed for heat transfer to take * place. *Very
slow air movement gains a bit temperature change, but at the expense of
proper circulation.

Slow air movement results in LESS heat transfer because
the air leaving is at a higher temperature and less heat is
extracted from the combustion gases. The more airflow,
the more heat that will be extracted, the more heat you
will get out for the same energy put in. But it's a diminishing
return, moving more air doesn't come for
free, and there are other considerations.