Chris writes from Port Washington, New York: "I noticed that in the crawlspaces of the home we bought last year, the insulation was installed in the floor joists upside-down, i.e., when in the crawlspace, the paper or vapor barrier is visible (faces the crawlspace) instead of it facing the "warm-side". Do I need to rip all this out and re-insulate? What's the worst-case scenario?"

Answer: We recommend that the insulation be flipped over. Leaving it the way it is could lead to condensation collecting in the fiberglass insulation and damaging the surrounding framing.