|
|
re: condensation on a/c ducts.
3 aug 2005
carolina breeze hvac wrote:
>> stretch wrote:
>>
>>>nick, if you put in a hole so small it would not cause problems, it
>>>would not do anything either. a pinhole will do nothing.
>>
>> then why are we led to believe it will fail a blower door test? :-)
>
>define "pinhole" :-)
ok. a hole made by a pin. i just miked 5 pins out of a sewing drawer,
0.0256, 0.0252, 0.0288, 0.0252, and 0.0286" diameter.
>every leak adds to the drop, and yes, you can have one too many..
>i mean, if its ok to have one, lets add another, it wont hurt anything.
you seem to know little about airflow or blower door tests...
an "airtight" 0.2 ach house leaks about 4 ach at 50 pa, about
1280 cfm for a 2400ft^2x8' house. the measurement accuracy is
on the order of 100 cfm. so...
1. how much pressure is needed to make 100 cfm flow through a pinhole?
2. how many pinholes are needed for 100 cfm of airflow at 50 pa?
3. how large must one "pinhole" be for 100 cfm of airflow at 50 pa?
4. how large must it be to remove 2% moisture by weight (which halves
the r-value) from 40 ft^3 of fiberglas insulation in a month, with
45 f ac air at 100% rh flowing from 1" h20 duct pressure, if the
insulation is in an 85 f attic at 50% rh?
5. how much energy would it "waste," if combined with an extra r19 layer
of insulation, compared to exposing a 20' r8 duct to hot attic air?
nick
|
|
