Q. You have written about electrical and gas water-heating units which produce instant hot water without the need of a holding tank. Where can these be bought and do you recommend them?
A. Originated abroad, instant hot-water heaters heat only the water as it is drawn. Thus, there is no need of heating or reheating water when the usage is nil or when the house is temporarily unoccupied.
Fuel savings are substantial, as you might expect.
One limitation to this fuel-bill-payer's delight is the need to sequence heavy usage of hot water. You may not be able to run two showers simultaneously or fill the washing machine while the dishwasher is operating.
See Popular Mechanics magazine, February 1982, for an article on instant-hot-water units. The article lists available manufacturers in the United States. Ask your reference librarian for the magazine.
Check with your local or state plumbing inspector as to the acceptability of the specific instant hot-water-heating unit that you propose to buy.
Two manufacturers are Thorn Gas Appliances, 25 Valley Drive, Suite 110, Greenwich, Conn. 06745, and Chronomite Laboratories, Inc., 21011 South Figueroa, Carson, Calif. 90745. The respective phone numbers are (203) 661-1600 and (213) 320-9452.
There are others, which you may determine from talking to your favorite plumber.