I have been having trouble with ash cakes when it gets below 20°F so last night I disconnected my oak and now no more ash cakes,my oak pipe which is flexible exhaust pipe for automotive use(wanted something rigid) goes up 4 feet and then out through my wall thimble will start to sweat at temperatures around 20°F, so disconnected and no more cakes was thinking about getting heat tape and wrapping it with that because I love my Oak.Any thoughts?