Planning or designing a "safe energy efficient house" requires that you do a lot of advance study. Present day house builders do not make changes very easy and you will find that not very many will even think about building you a house that comes up to this level of construction. The real place to start before designing or talking to a builder is to contact Building Science Corporation and check out "Joe's Top Ten" site . Be prepaired to think of home construction in a complete different way. They have it together!
Foam:POLYFOAM, Marketing Development Manager, Dave Faulkner, 888-774-1099