Third Blower Door Test – .24 ACH/Intus Performs

Today we had the third blower door test; the first since completion of the mechanicals (the two mini-spllit lines, the electrical, plumbing, and ERV.  I was a bit concerned because those items required almost 30 penetrations to the building envelope.

Most were for wiring.  I’m not using any recessed lights on the second floor, and I’m using sconces wherever possible (2nd floor hallway, master bedroom, and bathroom mirror lighting).  But each of the three bedrooms will have a ceiling fan, and the two bathrooms and two walk-in closets will each two ceiling fixtures.  That’s eleven holes through the 2nd floor (Zip) ceiling.  In addition, there are four exterior outlets (front and back were required by code, but I also put one on each side), and four carriage lights (two for the front door and one for each of the side doors).

We placed the main electrical panel on the (detached) garage.  But we still needed a conduit that runs to a sub-panel in the house basement.  I ran two additional conduits; one to provide for a switch in the house that controls the outside garage lights and a second that will allow me to put a generator panel in the basement while allowing the generator to be plugged in at the garage.

We had penetrations for the two mini-split lines (which I ran through a PVC conduit, the power lines to both mini-splits, and the 7″ intake and exhaust vents for the Zehnder HRV.

And finally, we had penetrations for two hose bibs and for to waste vent pipes (that join in the attic and exhaust through a single stack in the roof.

But I made considerable effort to ensure that every penetration was a) as small as possible and b) sealed properly.  In the end, it all seemed to pay off because the blower door resulted actually decreased to .24 ACH from the .38 ACH result of the 2nd test.


One note that I consider important: Given that I hadn’t made any adjustments to the Intus windows since the 2nd test, it now seems clear to me that they exhibited extraordinary performance.  In a previous post, I noted that there was some leakage through the windows during the 2nd blower door test.  But I’ve now concluded that, despite the fact that there was some leakage, the windows were responsible for a very small portion of the .21 ACH increase (it went from .17 ACH in the first test to .38 ACH in the second test).  I believe this because I made no adjustments to the windows after the second blower door test.  Therefore, the .14 decrease in the 3rd blower door test must be attributable to adjustments I made to the doors (I corrected the weather stripping on two of them) and the sealing of the electrical conduit (which fit tightly through the rim board, but had not been calked when we did the 2nd test.  Given all of this, at worst the windows could only be responsible for leakage of .07 ACH (.24-.17).  But that’s highly unlikely because some of that leakage must be attributable to the three doors, and some must be attributable to miscellaneous small leaks that are inevitable, and impossible to identify.  Considering the significant cumulative length of the window seals (only one two are fixed, the other 21 function) the amount of leakage that appears to have resulted (something less than .07) is, in my estimation, extraordinary.  Kudos to the folks at Intus!

So we’re now ready for insulation (which should occur this week) and drywall (which is scheduled for next week.  Hopefully, things will start moving more quickly..

Exterior Door Extension Jambs

As with the windows, we used Azek to build five-inch extension jambs for the doors.  However, unlike the window extension jambs, which used 3/4″ material, we used 5/4 thick Azek for the doors, and pocket screwed it into the door jambs (giving us a 1/4″ reveal).  We also used Wolf decking for the sill extension; which will match the decking on the wrap-around porch, and was just wide enough to extend 1/4″ past the final skirt trim (which will be 6/4 Azek below the door threshold).  The doors will use the same type of nailers and trim as used on the windows:

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