I am currently building a single family home in MD and our builder (Beazer Homes) has just switched their building practices in MD to adhere to the 2012 Energy Codes. Some of the 2012 Energy Code changes include:
1" dow board insulation before the Tyvek goes on
R15 insulation on 2x4 framed walls
R19 insulation on 2x6 framed walls
R38 insulation in the attic
low e windows
additional wrapping of all ducts
higher standards for blower door testing
no recessed lighting on the top floor
whole house mechanical ventilation system (I think)
My 2 questions are:
B/c my house will have the additional 1" dow board insulation along with the other energy code changes, is it possible for a house to be sealed too tightly?
As part of the redesign and to conform to the new codes, my builder is no longer offering dual zone HVAC systems. In the past there was always a system for the top floor and system for the basement and main level. My house has 3,000 sq ft between the main level and top floor and a finished basement of probably an additional 1,000 sqft. Here are the specifics of my HVAC system: Manufacturer is Goodman and the AC model # is GSX13 (4 tons) and the furnace is GKS9 (90,000 MBTU/h). This system is single zone.
I know very little about HVAC systems but this seems like it will not be able to properly regulate the temp throughout the house. Based on the info above what is your opinion? Is there anything I should ask the builder to change (although they probably would not)?