Hello,

I've settled on getting a gas tankless water heater (no need to rehash
the tank vs. tankless discussion). I realized that the place I want
to mount the tankless unit inside the house is on an exterior wall, so
I could just mount it on the outside of that wall. Is there a
downside? I'm in Berkeley, CA, so it doesn't freeze here. The upside
is simpler venting, and no need to get a sealed combustion unit (a
requirement in my mind for an interior unit).

Cheers, Wayne