So I just had my blower door test done. Note...i still have several unsealed conduits piped to the exterior. Since the code was started here in Chicago, my tester has tested hundreds and hundreds of homes in three years. Mine was the tightest. Even beat the passive house up the road. Just wanted to say thanks to the group here and will call out Dana for all the help and past discussions. I has to do a lot of the work myself and go in behind my contractors to "fix" stuff but it was worth it. My heat and a/c loads are very low and the heat pump has no trouble cooling a 3600sf house with it being 90 deg out. In the winter my radiant floor in the basement nearly heats the whole home. I passed final electric thus week and the solar guys will turn on the panels Wednesday am so I'm realm looking forward to this. I'm already approved for the REC program with bonuses for being an early adopter. With the rebates, my electric bill will be nil. People laughed at me with the exterior insulation and furring strips. But now that it's done and the benefits are seen they all say they wish their house was built that way. So thanks again....fun stuff! (but I wont do it again lol).

Kudos.

Congrats on the achievement. Could you share some of your approaches? Maybe some sections of stack-ups and any other insights? Successes like this can do a lot to encourage smarter building practices.

3cityblue, sure. I focused mainly on the walls since that represents most of the surface area and I had a ceiling to my budget.

Smartside siding
1x4 furring
headlok screws (4.5 in length?)
1.5 inches XPS 4x8 sheets insulation
0.5 inch OSB sheathing
2x6 framing
Great Stuff foam sealant around studbays and outside window bays and headers
Great Stuff window sealant inside window bay and window
R19 Batts Unfaced (regular fiberglass - I learned with little airflow and being kept warm, fiberglass is ~100% R-value ... and inexpensive and easy to "fix")
Certainteed Membrain vapor barrier
gyspum

I caulked all my bottom and top plates, king studs, etc where I thought there might be a gap

Foam sil seal around foundation also spray foamed all RIMs

I shot a one second shot of foam into any electrical conduit that adjoined closely to an exterior receptacle or fixture to block air infiltration

All ceilings upstairs are vaulted. There are no cans upstairs. All fan boxes to keep full insulation thickness (14in TJI rafters). All fan boxes also shot for a second in each conduit pipe with foam sealant

Wall between garage and home was rockwooled with Certainteed Membrain
Floor between garage ceiling and bonus room above was spray foamed

Roof is metal standing seam on #30 paper on 1/2 ply with a 2in air gap with R38 batts

HRV ducted to all baths and laundry for exchange air. Solar PV.

Since this was my home, I was very anal about making sure the insulation was done properly, fixing it or adding (and in some cases removing) insulation where it was not enough or too thick and compressed, etc. In a pure build expecting sub contractors to do good work, I'm not sure if the results will match. During every step of the way, I can tell the contractors were interested in what I was doing but saw the extra work and wouldn't do it. For example I did the furring strips myself. I did the membrain install myself. I went in at night and fixed insulation in every room. I caulked all the plates, I sealed around all the stud bays. The contractors used the cheapest caulk (Alex Plus), and hurried, etc. My cost to build would have been far greater had I employed the contractors to do this stuff. And I would have likely had to fix issues anyway.

Spray foam and caulk wouldn't be my first choice for an air seal that will continue to perform well after years of movement/expansion/contraction.

Surfsup: sounds like an excellent job. There are things I might have done differently, but that's OK. In the homes we build, we do subcontract most of the work, but we supply all the materials including the caulking, tape and other specific materials, and we also go in after the subs leave - as you did - and correct/redo/install what we need to. (But we also watch them like hawks so they do what they are capable of) It is difficult to get these guys to understand fully, but it is worth it!

Surfsup wrote:

R19 Batts Unfaced (regular fiberglass - I learned with little airflow and being kept warm, fiberglass is ~100% R-value ... and inexpensive and easy to "fix")

Actually R19s are only performing at  R18 when installed perfectly, in air-tight  5.5" deep 2x6 cavites, according to the manufacturers' own compress ion charts. That's a bit less than "~100% R-value" if looking at the labeled R:



At a 25% framing fraction (typical of 16" o.c. stud spacing) R18 cavity fill ends up being about an R1 lower "whole wall R" than if you'd used R21HD fiberglass, or about R1.6 less than R23 rock wool. 

The wall you have with the R19s & R7.5 XPS is about R21.1 whole-wall, which is code-min for climate zone 6, better than code for zone 5 & lower.

With R23 rock wool it would come in at about R22.7, with 7% lower wall losses than if insulated with R19s.

Whether the higher density batts are "worth" the upcharge varies with your goals & energy costs.   Low density R19s are really cheap, and going with R23 rock wool instead is the performance equivalent of adding another ~3/8"  of thickness to the exterior foam. (My own inclination would be to use something higher density, particularly in a wall.)