Replies

1. 
   DanH | Feb 23, 2016 06:13pm | #1

   The hard part is getting any sort of reasonable measurements.

2. 
   junkhound | Feb 23, 2016 07:16pm | #2

   Easy:

   take a piece of clear plastic tubing, fill partially with water - that is your manometer.

   Put an 'U' in it, with one end outside the house and the other inside.

   Buy a cheap anemometer from ebary or Harb Freight,   Dont rely on your 8000 and 6000 numbers, those are meaningless for a blower door type test. 

   Turn on the fan.

   Measure the air velocity diametrically across the whole house fan exhaust, and integrate the area/velocity product with time to get the actual airflow. Every 4 inches is sufficient, best to hold anemometer on a stick so as to not distrupt airflow with your arm.  If you do not know how to integrate, just condsider each 4 inch measurement as the velocity for a 4" wide annular area at the position you are measuring and adding the totals is close enough. 

   Measure the difference in height of the water column in the inside and  outside legs of the 'U' in the plastic tubing.

   That is your pressure difference in inches of water.  You maigh have to slant the clear tube to get a more accurate measurement. Search internet for manometer and you will see what is meant.

   The inches measureemnt is you pressure differential at the whole house caluclated airflow. 

   refer to any airtightness flow/pressure chart to rate your house.

1. 
   qc91 | Feb 28, 2016 04:41pm | #3

   Thanks thanks for the help I found  this would this

   work http://www.amazon.com/gp/product/B00N3PPZZY/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687682&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B000UV0F9U&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1HHVF62ANA0C2WSWBGMK

   also the Fan exhaust is in the attc I wuld have to have someon next the fan when it's on ? it a 30" fan

1. 
   DanH | Feb 28, 2016 04:53pm | #4

   The manometer is the easy part.  As JH said, it's just a clear hose with water in it.

   The anemometer is the hard part.

2. 
   junkhound | Feb 28, 2016 08:19pm | #5

   You need an anemometer also, there are 2 shown at bottom of page from your link.

   You can measure the fan airspeed and then go downstairs and measure the pressure differential, just dont open a door or leave the attic access panel open <G>

3. 
   joeh | Mar 29, 2016 08:28pm | #6

   DIY blower door

   http://www.builditsolar.com/Projects/Conservation/BlowerDoor/BlowerDoor.htm

   Joe H