"According to National Fiber's website a 2 x 6 wall at 5.5 " thick has an R value of R20 when dense packed at 3.5 lbs per cubic foot. The reason the Code has a minimum wall insulation requirement of R20 is because thats as good as it gets…"
"I've used XPS rigid foam on both new construction and retro-fit applications, the amount of rigid foam ( R value) will depend on the climate zone you live in, colder climate zones require a higher percentage of the balance between exterior…"
"I guess my first question would be what type of alliance have they formed? is Home Depot going to offer Energy Ratings or Audits at a reduced price? or is the concern that the rater may steer their clients to Home Depot for home improvement…"