On Wed, 14 May 2008 07:47:56 -0700 (PDT), Pauli G
wrote:

Hi Paul,
Thank you for your help. Historically, have energy prices kept the
same ratios? I'm just wondering if the relatively recent run-up in
oil costs put a monkey wrench in considerations - ie. should oil
prices stabilize, how would that effect cost estimates.

That's a great question for which I have no good answer. Historically
speaking, oil and natural gas have been more volatile and I suspect
that's going to continue to be the case for the foreseeable future.
Electricity does hold an advantage in that it can be produced by other
sources such as wind, water and nuclear which are not subject to quite
the same external pressures. To be safe, count on all of them
escalating at a rate well in excess of inflation.

Someone else mentioned time-of-use rates and off-peak water heating
which I think is an excellent way to go, provided you have sufficient
storage capacity and/or can shift a good portion of your DHW needs to
those off-peak hours (e.g., by scheduling laundry on weekends and
using the time delay setting on your dishwasher, if so equipped, so
that it runs overnight).

At this point, the operating costs of an oil or propane water heater
are 25 per cent higher than a conventional electric unit and some two
and a half times higher than a heat pump water heater such as the GE
model I mentioned earlier. If you are relatively low to moderate user
of DHW and can generate the bulk of your needs off-peak and still
avoid run outs, then a heat pump water heater + TOU rates strikes me
as the ideal solution.

Cheers,
Paul