Heat Pump Water Heaters - Page 2

 

Is the water ever really hot with that kind of setup? I have friends in
Massachusetts with that setup, and the only time the water is ever above
body temp is in the dead of winter when the furnace runs almost constantly.
It's ok in the summer, but lukewarm showers in January are not particularly
appealing. They plan to replace with an electric water heater as soon as
they can afford to, but it's their first house and money is very tight.

  h wrote:

Or just add a small (or very small) tank or tankless heater to bump it
up a few more degrees. You'll still have most of efficiency benefits and
energy is not getting cheaper.

   Jeff

 On Tue, 8 Apr 2008 00:37:35 -0400, <h> wrote:


To answer your question, they should provide plenty of hot water and
can heat this water up to 60C/140F (most electric tanks are set to 50C
or less to prevent the risk of scalding).  During periods of unusually
high draw when the heat pump can't keep up with the demand, the
electric element(s) inside the tank will kick on and so the water
heater will perform in the same way as a standard electric unit.

Have your friends checked and cleaned/replaced the air filter on their
unit?  If not, the condenser could be clogged with dust and lint,
which would severely impact its operating performance and,
potentially, its service life.  Have they also checked the tank's
upper element and thermostat?  If either has failed (not uncommon on
older tanks) or if the thermostat was turned down too low -- or was
disconnected by the previous owner so that heat pump would operate on
its own, in an attempt to maximize savings -- you could conceivably
run out of hot water during periods of high demand.

Installed correctly and with proper routine maintenance (basically,
nothing more than cleaning or changing the air filter), these products
should provide many years of trouble-free and economical service.  I
understand Massachusetts has some of the highest electricity rates in
North America and replacing a water heater with one that could
potentially use twice as much electricity doesn't strike me as a good
solution.

Cheers,
Paul

 On Tue, 8 Apr 2008 15:58:54 -0400, <h> wrote:


Well, 100F isn't going to provide much reserve capacity, so as cold
water is drawn into the tank, outlet temperatures will start to fall
off rather rapidly.  In any event, I would recommend the upper and
lower tank thermostats be set at 120F or 140F if the tank is equipped
with a mixing value to prevent scalding.  Given normal line losses,
being set at 100F, the temperature at the shower head may very well be
95F or less -- much too low for my liking.

Cheers,
Paul