Steve Lusardi wrote:

If you use a water cooled muffler as a heat exchanger to heat your fresh
water, at some point your freshwater tank will be hot enough.

Just curious, no one mentioned using the exhaust waste heat
for domestic water heating. I have never seen such an
installation and suspect it is pretty rare since for the
reasons you mention it is a cumbersome means to avoid using
heat from the coolant.

Rick