I have received conflicting advice regarding chimney caps. I thought
installing a lock-top type chimney cap with a built-in damper could help me
save some money on heating. My chimney sweep, however, advised me the
existing damper was working well and a sealing chimney cap would cause a
condensation at the top of the chimney when the hot air hit the cap, leading
to water damage within the chimney. He also said the loss of heat through
the chimney was negligible with a good fitting damper and what little air
did get out was good for air circulation within the house. In other words, a
chimney cap that stopped the rain was all I needed (the draw is fine).

Anyone care to weigh in on this one?

Thanks in advance

D. Charles