DO NOT PLACE TUBING IN THE LAST JOIST SPACE OR WITHIN 16" OF AN EXTERIOR RIM JOIST
The reason that exterior rim joists need insulation, is that the joist spaces get very warm and with the elevated temperatures the heat loss through the rim joist is greatly accelerated without proper insulation.
INSULATION AND CRAWLSPACES
NEVER PUT FOIL NEXT TO THE TUBING, IT BECOMES A CONDUCTOR.
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