The theme of my shop is, Putting lost heat back to work!

Fourty to fifty percent of the heat in my garage is donated by the pipe warmer, which is situated below the garage.

   Here is a better picture of how I heat my water heater with the furnace.  Flue heat from the furnace typically goes out of the shop through the chimney in my roof.  When I close the primary damper the heat is forced through duct work up through the water heater core.  The water heater essentially becomes the Flue/chimney. This system works great! The draw backs that I did not anticipate, are the corrosive nature of  the flue gases, and condensation that occurs from rapid cooling of the flue gases. The burner system for the water heater gets gummed up, and I need to clean it before I use it as a normal water heater again (when the furnace is off).

  Thanks for listening, Pablo