Instant Hot
Water-Maybe
by Alex Wilson
Demand or instantaneous water
heaters have been widely used in
Europe for several decades and have
been available in this country for ten
years. They have been extensively
promoted through advertising
campaigns, magazine articles, and
building trade shows. Demand water
heaters only heat water as it is used,
so there are no stand-by losses-the
primary culprit of low efficiency in
conventional water heaters.
Yet demand water heaters have
failed to achieve a significant market
share in the U.S. In fact after
numerous calls to progressive builders
in my region, I was unable to find a
single builder who regularly (or even
occasionally) installs them into
homes. Why?
Counter-intuitive
techniques had to be
learned to regulate water
temperature. It took
practice, and