what is the point of using high R value insulation in your building if the wood studs throughout have a poor R value.

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Wouldn’t your insulation effectively work like Swiss cheese?

Edit: while I have your attention, would you bother insulating a detached building that is NOT temperature controlled 24/7 like a house? It’s a hobby workshop. My thought process is that the insulation would only be paying it self off in the winter + while I’m in it + after whatever amount of energy I would have spent heating it WITH insulation. To me it just seems like the break even would be sooo far in the future…

Edit Edit: I’m not so concerned about the summer. I have a couple ceiling fans and a few attic/gable fans that help dissipate heat.

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Yes, it does work like Swiss cheese. But Swiss cheese is a hell of a lot better than no cheese at all. When you use High R insulation, you’re limiting the space for thermal exchange

It still raises the value of the wall

The stud provides a relatively narrow conduction path through the wall, only about 9.5% of the area of the wall is studs (1.5″ stud 16″ on center) which still leaves 90.5% of the wall that you can adjust the heat loss through

If 10% of your wall has an R value of 4 from the studs but the remaining portion is 15 from the fiber glass insulation then the overall wall ends up with an R value of almost 12. If you only use poor insulation with an R value of 6 then the wall end up closer to 6 losing twice as much heat to the outside.

For a practical example. If your garage door when closed has gaps around it, is it even worth closing it to keep the garage warmer? Absolutely! Because while the gaps have terrible insulation you can still fix the vast majority of the issue by having the door shut (aka insulating the rest of the wall)

It does, but the structural supports make up a comparatively smaller portion of your wall compared to your insulation, and the studs are going to be there transferring heat either way. Might as well compensate for that by making the rest of the wall more resistant.

It’s like if you had a winter coat and a t-shirt, both with a hole in them of the same size and shape. Yeah, the hole isn’t ideal, but the winter coat will still keep you warmer.

The amount of heat transmission is pretty much a function of area. So the greater the area of good insulation to poorer insulation, the more total insulation is obtained.

Yes the r value of a wooden stud is poor, however that stud isn’t the only thing that makes up a finished wall. You have the drywall touching it, the exterior plywood, the sheathing, and exterior siding. Overall from interior wall, through the stud, to the outside air is about an r value of 8. Coincidentally that’s the code requirements for most modern buildings.

However going higher does help with overall energy efficiency because you can calculate heat lost as a property of surface area over time. If more surface area is more insulated then you lose less energy overall.