In part one of this post, guest contributor Jeremy Begley talked about why equipment replacement without any kind of thermal measures was rarely done. In part two this week, he details why that's the case.

Way back in the late 2000s, when I first took my BPI Building Analyst training and got into home performance, one of the first lessons I can remember learning was the importance of working through the proper order of operations. Things like "always seal the high and low bypasses first" and "air seal then insulate because the pressure boundary and...