warming basement

[SIKSUKR]

Originally Posted by willcastner

This is true with a unisulated basement. People don't realize a 8-10'' thick concrete wall has the same R-value(heat conductiving rating) as a .75'' sheet of plywood.
.

Very true however,Most basements are just that,in the basement and mostly below grade so the ground becomes your insulation.

[Belmont Resident]

Originally Posted by SIKSUKR

Very true however,Most basements are just that,in the basement and mostly below grade so the ground becomes your insulation.

We went up our camp this past weekend. It has a 24" crawl space under with skirting covered with 2" insulation with 3 feet of snow banked up all around. Temp outside was down near zero when we got there but the area we have taken off of heat and drained the pipes to conserve fuel was at 42 degrees.
Ground heat coming up keeping it warm? Not sure but it definitely wasn't heated by me, either way I was happy.

[willcastner]

Originally Posted by SIKSUKR

Very true however,Most basements are just that,in the basement and mostly below grade so the ground becomes your insulation.

This is true with below grade but the heat loss above grade is tremedous. Any time you have a surface area gaps and voids of 5% cut your R value in half. So basically the heat is rushing to the uninsulated above grade portion at such an accelerated rate it doesn't matter what is going on below grade. Insulation to 1ft below grade is the most cost effective way of going about it. The only difference is when you have a rock wall foundation you want to bring the foam down to the floor to get the foundation air sealed preoperly.

[DickR]

Originally Posted by willcastner

....Insulation to 1ft below grade is the most cost effective way of going about it.

I think that depends on your definition of "most cost effective." Given that code requires footings to be 48" below grade, to ensure they're being below frost line, the soil can be quite chilly well below the first foot. Also, the concrete conducts heat readily (R nominally only 0.08/inch), so that inside heat absorbed by the concrete well below a short insulated area will be conducted upward to the above ground portion as well as directly outward to chilly ground. If it's deemed worthwhile to insulate part of the foundation wall, it's worth it to insulate all the way down to floor level. Aside from fuel savings, the dramatic improvement in comfort in the basement will be worth it. The floor above the basement ought to feel warmer above also, if uninsulated.

[nhboat61]

I want to say thanks for all the advice on my original post. So far, we have maintained about 45-47 degrees all winter in the basement using the dryer vent system.

There appears to be no evidence of any moisture or mold at this time something we have to monitor .