This is a question of economics, not just
fuel efficiency and saving the planet. Yes, tank less water heaters will save you some on your current fuel bill;
however, the installation cost to retrofit a tank less water heater in an existing dwelling with a tank-type water
heater can be prohibitive.
If you take your fuel bill, say in the
hottest month like August or July, and then divide the cost of a new tank-less water heater, installation
and annual maintenance/repair cost by that number, you will come up with the time, in months, it will
take to pay off your investment.
The problem with tank-less water heaters sold
in the U.S., as opposed to those sold and installed in other countries, is the excessive use of safety features.
These safety features require that an electronic circuit board installed in almost every tank less water heater
sold. These parts are unnecessary. We have survived with the use of thermocouples, safety valves and TP&R
(Temperature and Pressure Relief) valves for many years now.
Another factor in installing a tank-less
water heater is the quality of water we use here in the U.S. It sucks, plain and simple. We use some of the hardest
water known to man in this country. Without installing a water softener, or water treatment system, the efficiency
of any water heater, whether tankless or not, is on a downhill slide as soon as you turn the unit on. The
minerals in the water separate and buildup on the walls of the heat exchanger almost immediately; this coating
of debris kills the whole point of a tank-less water heater being energy efficient.
True, if you handle the annual maintenance
yourself, it will save you a little money, around $100+ dollars a year, depending on your geographical location. If
not, be sure and add this cost to the final installation bill.
If you are building a new home, now is the
time to plan a tankless water installation. The builder can easily work in the optimum placement in the homes
structure, and size the fuel supply and venting of the unit; unimpeded by current structural restrictions.
Tankless waters heaters do save energy, and
will help save on fuel cost. The decision is up to you.