[img]/forums/images/icons/smile.gif[/img] As soon as I read your description, Pat, I recalled seeing the engineering article on the Alaska pipeline and the self-conducting heat removers. It has been a while so I didn't remember the principle and in any case it wasn't explained as well as you have explained it here. I can see where the heat pipe system would be a huge benefit to an A-coil because of the way it spreads the dehumidifying over a wider area and reduces icing. [img]/forums/images/icons/smile.gif[/img]