Wednesday, April 18, 2012

Monday, April 16, 2012

Today is cleanup day and getting ready for the Blower Door Test.  This test will check for air leaks before the drywall is installed.  I am hoping for good readings but I know that there are two main areas of leaks I could not close up: 1.  the pipe going out the roof for the stove is about 10 inches in diameter and will cause large air movement.  and 2. the openings around the ERV tubes are a big air leak that has to be addressed.

Most of the other openings I have closed up such as the vents for the drains, vacuum system which goes into the Mechanical Room and drains for the water heater and mini-split.

The guy from Austin Green Team brought his equipment and set up the test.


The test entails creating an environment that simulates a 20 mile/hr wind blowing at the house from all directions.  Then the best way to find air leaks is to walk around the house and it is obvious where the air is blowing into the house since the lowering of the pressure in the house actually pulls air in through any place the air can get in.




The blower is placed in the closed doorway and blows outside until the pressure reaches 50 Pascals...just a way to measure the pressure.  The most accurate measurement includes an accurate measurement of the volume of the area.  Since we only knew the square feet (2155 sq ft) and guessed the height to be an average of 18 ft,  the cubic feet per min measured 1505 which meant about a 11 percent loss of air per hour.  The guy said an average house has around 35% air leakage.

Bottom line:  I have a tight house even with the holes I know about.  When we modified the volume to 13 ft average height the loss went up to 17%...still by Austin Energy Standards==a tight house that requires ventilation.  Great, because I have ventilation.  I think I can get the cfm down to below 1000 when the drywall is on but then the volume will also reduce.  It was a worthwhile test to see how much air leakage I have at this stage. It will only get better.

What was most helpful was checking where the leaks were.  Some were surprising to me but fixable with more spray foam, ZIP tape or tightening the latch on the double doors.  None of the windows had air penetration.

Drywall stocking and hanging starts tomorrow.

No comments:

Post a Comment