Related profession - contractor/developer. Fair amount of experience in HVAC from that perspective in terms of subbing and specifying work, but have never grazed anything. I like to understand anything that goes into a house well enough to be able to do my job, and have had to trouble shoot a fair amount of stuff over the years. I know enough plumbing to have some strong ideas about hot water heating (grundfos over Taco!)

I know enough to know how little I know, and I'm here to learn, especially about heat pumps and instant hot water heaters, which I think are the way of the future