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DIY Blower Door Test

qc91's picture

Hi, I wanted to findout If I can DIY my Own  Blower Door Test,  are House has  Whole House Fan that can moves 8000 cfm on high and  6000 cfm  cubic feet  per minute on low can we use the  Whole House Fan like a Blower door?

 

Thanks 

The hard part is getting any (post #212715, reply #1 of 6)

The hard part is getting any sort of reasonable measurements.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Easy:   take a piece of (post #212715, reply #2 of 6)

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.

Thanks thanks for the help I (post #212715, reply #3 of 6)

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

The manometer is the easy (post #212715, reply #4 of 6)

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.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

  You need an anemometer (post #212715, reply #5 of 6)

 

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>

 

 

 

DIY blower door (post #212715, reply #6 of 6)