A system includes a tank containing a fluid to be heated; a U-shaped pipe disposed proximate a bottom of the tank, a majority of the extent of the U-shaped pipe being disposed within an interior of the tank; a catalyst unit embedded within the U-shaped pipe, the catalyst unit comprising a catalyst wrapped, natural gas filled, perforated pipe that is configured to enable a catalytic reaction on its exterior; a vent pipe attached to the U-bend pipe which allows air to circulate; and mechanical controls disposed proximate the U-shaped pipe configured to vary temperature output.