Recently, I visited Peter's house and I now have some more details. His SIP walls are R25 and his ceiling is R42. It also took him 3 years to get a building permit, and finally to build it in 2004. He has a beautiful hot water system and hydronic heating/cooling, with a central manifold, so you can control every leg from a central location. He now regrets having tried the hydronic cooling, for it is giving him a condensation problem. So he is ready to switch to an ASHP and I am working with him on that project. Meanwhile, based on the load calculations, he needs 4 tons for the whole house, which is about half of what my g/f in Stamford, CT needs for a similar size house, but of traditional stick construction.