< sigh> The wetbacks aren't all that common here. It's too bad, because with a family of four at least half of your domestic energy needs are for hot water.

Figure that the wood stove is already running ... why not use it to make hot water ? (It saves a lot on the electric or fuel bill.)

I built my system about ten years ago. The total cost was under a 100.00 USD

I salvaged an 80 gallon stone lined water heater from the municipal metals pile. I pulled the upper and lower heating elements and used those tank taps as the inlet and outlet for the heat exchanger. I built the heat exchanger out of 3/4 copper pipe & fittings then mounted it about 8" away from the outside of the stove.

The stove throws off heat. The heat exchanger takes that heat and heats the water inside. That starts a thermosiphon. As the heated water travels to the upper fitting on the tank it draws in colder water from the bottom of the tank. Easy peezy. Runs all day and by early evening we've got a tank full of 140 deg F. hot water. No pumps or moving parts so the system should probably last at least 40 years.



The main reason that the wetbacks have a reputation for overheating the water and making steam is because people don't use common sense when they're building them. If they would just set them up for moderate gain there would never be a problem.