who/what/where/when/why/how: good except your where = climate =
recovery rate.
there are other options for using hvac systems waste heat and an
architect gives you a better answer.
but from cold water 33 degrees in buffalo ny to 150 degrees of hot
water is faster than yours will be on our big 75 gallon natural gas
tank. you'd get two big electric tanks with as many timers as you can
to run the two tank elements in each. and the circulators.
electric hot water has slow recovery, so now that we see you have cheap
electric available you get the largest residential tanks and you don't
run out. you can run the electric recirculator pump on a start time of
day like 15 to 30 minutes before morning shower time. adjust the tank
temperature high enough so you can run as many of the devices as
possible.
see:
http://www.terrylove.com/wh.htm
more at:
http://www.eere.energy.gov/consumer/.../mytopic=12760
heating cooling calculator at:
http://www.hvacopcost.com/