I feel certain its caused by contraction and expansion because it doesnt do it in the summer when we have no heat on. At the time we had the heat installed it was relatively new and I think they just didnt know what they were doing. I'm not exagerating when I say, it's impossible to sleep when the heat is first turned up in the morning.My next question, could we d/c that and put new panels over top, would that solve the problem?