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Tankless Water Heaters - Another Good Idea Gone Wrong

Tankless Water Heaters are popular as a substitute for a tanked heater – Where is the Benefit?

Not long ago I completed a project in central Texas.  While in the planning stage, the owner indicated to me that he wanted to install a tankless water heating system in the space.  I asked him how many he wanted installed.  He gave me a look as if I had asked him how to hang a door.  He knew me as a knowledgeable professional, so his surprise at my ignorance of tankless water heaters took him by surprise.  I bid a project not long ago where the owner indicated where he wanted his tankless water heater to be installed.  I asked him where he wanted the others installed.  Another home owner gave me ‘the look.’

Some time around 1927 Dr. Stiebel Eltron invented the immersion heating coil system in Berlin, Germany.  The technology was used sparingly in industrial applications in Europe until the mid 1970’s when the pressures of a troubling “Energy Crisis” rocked the world.  Since then, tankless water heaters have become increasingly more popular here in America.  Today the technology can be purchased very inexpensively.  The drawback to the use of the tankless water heater is that it serves no benefit over tanked heaters as most builders install them.

The Correct Term is On-Demand Water Heater

Go back to the fundamental reason for a tankless water heater.  The correct term for the unit is not ‘tankless.’  The correct term for the technology is ‘on-demand water heater.’  The feature that is most attractive, and the singular reason the technology was developed, was to shorten the time it takes to deliver hot water to your sink, tub or shower.  The idea of continually heating 40, 60 or 80 gallons of water in a heated reservoir seems not just wasteful, but ridiculous.  Conversely, if a tankless water heater is mounted centrally in order to service an entire home’s water heating needs, the result is that the water lines in the house take on the same function as the tank on the traditional water heater.  Hot water is delivered at the same delayed pace and the tankless heater burns more energy than a tanked heater would have consumed to perform the same task.

When I design a project, I recommend individual on-demand water heaters at each bathroom and in the kitchen.  Usually the laundry shares with either a bathroom or with the more powerful kitchen unit.  Both electric and gas units are available.  There are positives to both energy sources.  Gas units heat more efficiently and with greater normal heating ranges than the electric units.  They do, however, require outside installation and expensive venting systems, and they are considerably more expensive than the electric units.  Electric units are easily installed under vanities or in utility closets.  They are affordable and easily installed.

Plumbing supply houses and plumbers generally  sell and install large, high capacity central tankless units.  The industry has accepted the senseless standard and addresses an eager public demand for the technology delivered in this way.  Very few general contractors, plumbers, supply houses, and home owners understand the actual use of the equipment, so when I address the use as I understand it, I am often ridiculed until knowledge sets them free.

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