A solid fuel burner can be used to heat water in your house by means of a heat exchanger, commonly known as a “wet back”. Cold water is run through a coiled copper pipe or similar heat exchanger that is connected to the burner where it absorbs heat from the fire.
Wet backs are generally used as a secondary source of heat to supplement a conventional electric hot water system. They can be used in combination with solar water heaters to heat water when it is a cloudy day.
Beware that if you fit a wetback to an existing burner and the heat exchanger lies within the fire box this will likely compromise the efficiency of the burner and could result in higher than acceptable particulate emissions.
You should talk to a reputable supplier before installing a wetback to an existing burner or purchasing a new solid fuel burner with wetback.