I have read multiple sources on the internet suggesting use of 2" XPS foam boards to insulate basement foundation and then building a 2x4 wall in front of it.
2" foam board is very expensive when compared to 1" foam board and I am wondering if I will get the same/better results by following EPA air plus recommendation (link below) of using 1" XPS on the foundation and then filling the 2x4 cavities with fiberglass insulation.
As I missing something or do you think I have the right plan ? I'm in South East Michigan and I have a walkout basement(last year temps dropped below zero for 2 weeks- usually worst night time lows are close to 15 deg F) . The basement gradually goes from 90% below grade to 100% above.