15 years old, uses a 75 gallon gas water heater in the garage via PB pipes.:shock:
Circulating pump inside the attic unit. Looks very simple, just an old chevy radiator in there probably. 
Client does not like it and will likely replace it.
Its a big tea kettle.
Bruce that was a still
We have the outdoor wood boilers all over here. (they are commonly referred to as boilers, however they are merely hydronics systems.) I had the pleasure of inspecting and promptly disclaiming it in the report. I have since gone out of my way to learn more about these. I want one, but at 5-6 grand, it will take several years of heat bills in one check to pay for it.
This one is a “poor man’s boiler”. The water heater only lasts 10-12 years while a boiler tank would last much longer.
I like the simplicity of it and wish I knew what the operating costs were. I would guess no real savings or you would see many of them, especially since natural gas prices are usually high.