I'm personally not a big fan of using closed cell as a full air barrier for an attic. Three inches of open cell is far greener, and seals just as well, at a lower cost, and delivers twice the R value.

This goes double if the closed cell foam is blown with HFCs (the standard is HFC245fa) rather than HFOs (HFO1234ze).

Open cell foam is blown with very low impact water, and 3" of half pound open cell foam uses only 3/4 the polymer of 1" of closed cell.

The CO2e footprint of HFC blown closed cell foam is substantial per rated R-value, and even HFO blown foam has a pretty hefty hit:

https://materialspalette.org/wp-content/uploads/2018/08/CSMP-Insulation_090919-01.png

There may be a case for using closed cell foam to seal and insulate air conditioning ducts, since moisture from the outdoor air in a vented attic can migrate into the open cell on AC supply ducts if the AC is running at a high duty cycle. It's also easier to do a decent job with closed cell in tighter areas and awkward shapes than with open cell.

Okay, had the envelope guy back. I misunderstood option #2. It's not 1" of closed cell everywhere. It's essentially:


Attic:

1. clean out ALL old insulation

2. install the can light covers

3. seal all accessible penetrations, top plates, wire/pipe penetrations, etc. with closed cell foam to air seal attic floor - there are some areas where they will box in areas with foam board as well

4. encapsulate duct system with spray foam spraying over existing insulation with 1" closed cell spray foam.

5. insulate to R-60 with cellulose tru-soft insulation (normally R-49 - special now offers R-60 for free upgrade)


Basement:

1. closed cell spray foam in storage room ceiling (area under concrete floor from screened in porch) - this room has another interior cinder block wall separating living space from it, but the ceiling area is metal (under concrete) and that area is much colder than rest of house. I figure if we foam seal it, less cold will permeate through the room and potentially into living space next to it.

2. spray closed cell foam to rim joist areas by removing drop down ceiling tile to access, spray/seal all accessible rim joists in basement, and reinstall drop down ceiling tile.


Garage attic:

1. clean out ALL old insulation

2. add blown insulation to R-30 level

(this is a 20x22 garage area, and they would charge $600 to clear out old insulation and $1200 to add new insulation - wife wants this done for her peace of mind....)


They will perform blower door test BEFORE and AFTER work is completed for comparison for me.