Going over my year end usage and costs today I was thinking of my summertime DHW. I'm currently burning year round, and now I'm questioning if I really should. My current DHW setup is a 40 gallon Vaughn storage tank off of the boilers' tankless coil. I'm averaging 450-500 pounds a month from May-September. I also fight the July and August outfires when I lose draft. I was thinking of one of those hybrid water heaters when the power company rebates were good, but that's a lot of money for a crap 5 year tank and a Chinese heat pump. I'm thinking of getting one of those Nyle Gyser heat pumps and pipe it into my existing storage tank. I'd valve it so I'd have two loops, one loop to the boiler and the other to the heat pump. It's a pain to keep the boiler going in the summer, and seems like a waste of coal. I never run out of hot water though, but my basement is HOT!! It's unusually warm down there without the boiler running, so a heat pump would have no problem getting a source.
Anyone here run one of these? I'm wondering what it would cost a month to run and if I'd have enough hot water.