On 30-Mar-2004, "News" wrote:

Using high efficiency condensing water heaters will bring different results.
The lower the return temperature the more efficient they are. If you allow
a tank of water to cool and you re-heat it with a condensing water heater
the re-heat is very efficient in fuel use.

I've never seen a water heater that was designed to condense water on the
outside. In fact, I can't understand how that could possibly happen since the
shell of the water heater will be hotter than the surrounding air.

Moisture condenses when warm air encounters a cooler surface; it does NOT
condense when encountering a warmer surface. Have you ever seen a cup of
coffee condense moisture from the air -- no, of course not. A cool drink like
iced tea condenses moisture.

You may see condensation on the outside of a refrigerator, but you're not going
to see it on the outside of a water heater.