I was running my hands over some interior walls (and the other side happens to be exterior facing / exterior wall), and noticed some spots feel warm where most other spots would feel cool/cold per the ambient temperature. The warm spots seem like they have a spacing pattern of every foot or two away from a warm spot you'd find another one.
I didn't seem to notice such on an interior only wall, but I haven't checked throughout the house.
Is this normal?
What would cause the warmth? Insulation (holding heat), electrical wiring, HVAC ducts (though the home doesn't have any), hot water pipes inside walls (though I'm assuming this would cause more of a straight horizontal line of warmth than every few feet)? A leak in something?
Assuming your house is wood frame construction, the warm spots *could* coincide with each stud in the wall. Wood is a very poor insulator (even at 5-6 inches thick) and transfers heat from in to our, and out to in. The spaces between the studs would of course be insulated, but the spot where each stud sits has no insulation at all, unless you have rigid foam or something else on the exterior of the house.
I'm guessing this is on a wall that was receiving direct sun... yes?