HVAC, Home Climate & Heating/Cooling efficiency are a fascinating topic, a lot of physics & engineering are involved in making a comfortable home. Many updates coming soon!
Spray Foam Insulation Technology
Despite some graphs showing diminishing returns with increasing inches of polyurethane foam, what needs to be kept in mind the is the delta T between outside and inside. This is especially crucial for controlling humidity. There are some horror stories out there for critical operations, like an industrial meat freezer, which was under foamed and had severe condensation issues. The extra inches are protecting you from humidity changes, very important for keeping your house dry & protected.