[S-F]

A note about GreenFiber. I believe this is what's sold at Home Depot? One Sunday I had to get a boat load of that stuff (over 100 bags) because the lumber yards were closed. We ran out of National Fiber cellulose part way through an attic open blow. It's dusty! And it stinks! It smells like horse urine when exposed to moisture (ammonium sulphate). The dustiness alone makes me question it. All of the other brands I have used like NF (100% boron borax) and Green Seal (Also contains ammonium sulphate) are more like fuzz and less like dust. So I have my doubts about the quality of Green Fiber.

The design temp for the calcs I gave were -5 and 70. The problem with a manual j, even one done by a very intelligent, informed, patient and observant individual is that it still doesn't cover all bases properly. By the sounds of it your house should probably out preform mine. My walls are 2x4 with little insulation at all. My windows aren't worth a.... well, they're not good. My walls are board sheathed. I have some things going for me though. The house is a ranch which is not only the easiest type of house to work on, it is also inherently the tightest due to simple geometry and lack of a band joist and so on.

What's in your walls? Have you dense packed them? You have R-10 on the sheathing? Nice! I'm jealous. How did you make R-10? Sounds like 2" of XPS. A 4,000 Sq. Ft. house could certainly be 40,000 btu/hr if the air sealing if handled properly. If it's passivehaus like it could probably be 1/2 that. People are nuts when it comes to building envelopes. I want to cry every day when I go to work and see these houses, many of which are less than 20 years old.