As a plumbing contractor for over 30 years, an instructor for almost as long and now working for greenplumbersusa I have learned, as you have stated, that one solution to differing situations is not the answer.

I also know that there are ‘enlightened’ plumbers who do know quite a bit about electric tank and tankless type water heaters. You should not generalize.

About electric heaters: While the initial cost is somewhat lower, a standard tank type electric heater will recover at less than 1/2 the hourly rate of a gas heater and usually at least twice the cost per gallon. Tankless electric water heaters work on as little as 30 kWh

As far as hot water distribution is concerned we teach:

1. Improve the Use
2. Reduce the Waste
3. Increase the Efficiency
4. Increasing the efficiency is NOT solely the function of the water heater or the piping system. Flow rates, Delivery times and Individual behaviors play just as big a role

8 truths about water heaters:

All storage type water heaters lose energy in the “standby mode” through the sidewalls and top of the tank even though they are insulated.

A typical gas fired storage water heater also loses energy from the center of the tank through the flue.

*Tankless water heaters can save energy by minimizing standby losses.

*Tankless water heaters can provide an almost unlimited supply of hot water, but do not get heated water to a fixture faster than storage water heaters.

*Tankless water heaters may increase water consumption.

*Tankless water heaters may increase energy consumption.

Minimizing the pipe size and length will reduce energy loses for any hot water system.

Locating the water heater as close to the the demand as possible and insulating the piping adds to the reduction.

*As it relates to tankless water heaters: You have to start with what is the motivation for installing a tankless heater? The potential is there to save energy if the users behaviors remain unchanged. If the users behavior remain unchanged water use will remain unchanged (there will be no water savings and in fact, water use will be slightly increased because there is a no hot water to deliver for several seconds after there is a demand).

If, on the other hand the user’s behaviors does change, because there is now a continuous supply of hot water and they or some other user on the property take advantage of it, both energy and water use will increase.