Just get a used electric water heater tank - say 50 gallons. Then remove all
the insulation around the tank. Remove the electrical wiring.

-or-

Buy a new water tank which can be pressurized to city water pressure levels.
(I think water heater tanks are tested to 300 psi, but actual pressure would
be from 30 psi to 100 psi.)

Then connect this tank *before* your existing water heater.

This would be pointless upstairs in the winter. You would be using more
house heating to warm the tank. In an unheated basement or furnace room,
might reduce expenses? And of course in the summer, it would be a money
saver if the city water temperature is colder than your house temperature.

More savings would be with a "heat exchanger" tank and a solar water heating
system.




"Ray" wrote in message
Recently I read somewhere that it's possible to add an auxiliary tank to
supply water heaters.

The purpose is, water comes from underground into a storage tank, where
the temperature of the water is raised by ordinary basement
temperatures -- especially in furnace rooms.

This water then feeds water into the heating tank at a considerably higher
temperature, thereby saving energy costs.

This is common sense. Is this technology available now?