How do I explain the inefficiency of 2″ polyiso walls in Northern Vermont politely?
Hi, I have some clients who have had experience with building Timberpeg homes in the past. They continue to insist that the homes they built were energy efficient despite being insulated with 2″ polyiso in the walls and 3″ on the roof. This is wildly inefficient in my experience. I build timber frame homes with SIP walls that are 6-10″ thick. I have presented them with charts showing r-values and also sent them links to your articles about rigid foam.
They built a house in Victory, Vermont using that 2″ wall and 3″ roof and say it was very efficient. They claim that during a period of -20 degree weather the power went out for three days and with no heat source the inside temp stayed at 68 degrees. I know this could not have happened. How can I explain the impossibility of a heat loss scenario like that in a clear, polite way without insulting their intelligence or worse, possibly loosing my chance to build them a beautiful timber frame. I am only doing the frame and they will be doing the rest of the house, but I feel the need to express my concern about their design.
Note: After much back and forth they are asking if 3″ walls and 4″ roof is better. While I agree it is “better”, I still do not think it is “enough”. It is a single story 1500 sq.ft. house and has the same footprint walkout basement. It is being built in East Charleston, Vt.
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