On May 15, 11:03*am, Pauli G wrote:
On May 15, 11:27*am, Paul M. Eldridge
wrote:





On Wed, 14 May 2008 10:34:13 -0700 (PDT), zzyzzx

wrote:
The hybrid water heater in the link provided above looks interesting,
but wouldn't that essentially provide air conditioning for my basement
(which doesn't need it at any time of the year). *It does look like an
interesting device for people who live in warm climates and don't have
the water heater in their basement. *Unless I'm mising something here?

Generally speaking, most homes in New England have full basements and
this is where the water heater is normally located; this area may be
finished or unfinished and, by extension, conditioned or
semi-conditioned. *For roughly six months of the year, a HPWH would be
pulling heat from the home when there is presumably at least some
heating demand, while during the remaining six months it would provide
free dehumidification and cooling.

That could be key. *Living on the coast, I run my basement
dehumidifier seemingly non-stop from May through September; otherwise,
I run into serious issues with mould and mildew and musty odours. *If
a HPWH eliminated that demand by providing both hot water and "free"
dehumidification, it would save me about 1,800 kWh/year (i.e., 150
days at an average of 12 kWh/day). *So, in this case, not only would a
HPWH cut my water heating costs in half, it would eliminated the
second largest electrical load in my home after my heat pump.

With respect to winter operation, we should still come out ahead.
Assuming the HPWH is located in a fully conditioned space that is
heated by oil (arguably our worst case scenario), it would likely
consume 10 to 12 kWh of space heating demand per day depending upon
how much hot water is used. *It then becomes a matter of comparing how
much oil would be used by the OP's boiler or furnace to supply the
heat subsequently taken away by the HPWH versus the amount of oil that
would be needed to provide the same amount of hot water using a
conventional, stand-alone tank. *Most oil-fired boilers and furnaces
have an AFUE of 75 to 85 per cent -- a conventional, stand-alone
oil-fired water heater would have an EF of 0.50 to 0.55. *Thus, to
generate the same amount of hot water, an oil-fired boiler or furnace
"feeding" a HPWH would consume about one-third less oil than what
would be required to operate a stand-alone tank. *Moreover, an
oil-fired water heater would suck conditioned room air up the stack 24
hours a day whereas an electric or HPWH would not.

When you add it all up, a heat pump water heater makes a lot more
sense, even when your electricity costs are almost double the national
average.

Cheers,
Paul

Hi Paul,
I have talked with my plumber/HVAC guy and canceled my order for the
replacement Bock oil water heater - I'm going to convert over to
electric water heat now. * Question: * what brands/models do you
recommend? *I know I should get a 9 or 12 year warranty one, but
anything specific that you like brand wise? (50 gallon)- Hide quoted text -

- Show quoted text -

Get what has the best insulation and install thermal breaks on the
water lines at the heater.