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Are Tankless Water Heaters a Good Investment for YOU?

In response to a reader's question...

Dear NH,

What do you think about tankless water heaters?  I love the idea. When you turn on your hot water knob, the unit heats water as it enters your house. There is no tank to collect sediment, or constantly heat water you may not use. Do you recommend them? Have they been on the market long enough to be proven reliable? My local Home Depot doesn't carry them -who would I call- a plumber? Can you recommend any particular brands?

MD from Venice, FL

Dear MD,

I think tankless water heaters are great, but have some limitations that make them unsuitable for some users. They were originally designed to be used in situations where a tank is undesirable and/or inefficient, such as a building with very minimal hot water demand. They are more commonly used overseas than in the US, probably because we are not as attuned to the economy and space saving attributes of these water heaters.

Since the water is heated as needed, there can be tremendous savings over tank units that by design keep the water hot all day, every day. And there are other more conventional alternatives that may be as good or better. For example, the energy (and
dollar) savings are diminished or even nonexistent if the alternative is a hot water system integrated into your gas or oil heating system. If the price of gas or oil is especially low in your area, a standalone tank unit using these fuels may be competitive if you take the extra effort to superinsulate the tank (via wrapping the tank with insulation) and keep the temperature down to under 120 degrees.

There is a tradeoff you must understand before making a purchase decision on a tankless water heater. Tank-type water heaters can supply enough hot water to run multiple hot water appliances or showers at the same time, provided you buy a unit with sufficient tank size for your projected usage and the size of your household. Of course, they can run out of heated water, since they have a limited capacity.

Tankless heaters, on the other hand, have large drop-offs in water temperature as the water flow through them increases. The elements in a tankless water heater heat the water up to an adjustable maximum temperature. As the incoming water temperature drops, or as the volume of water moving through the heater increases, the temperature of the heated water will correspondingly decrease. Of course, this negative feature can be overcome by changing your hot water usage habits... for example only using one hot water appliance at a time, scheduling showers at different times than other members of your family, etc. You may even install more than one tankless water heater in your home to serve different "zones".

One the positive side, with a tankless unit you never run out of hot water, since it heats on demand. We all know the frustration of having the stinking hot water tank run out of heated water during that critical final rinse! You know... the one that really counts!

There are a number of companies online that sell these units. I cannot give a product recommendation, but I suggest that you get the written manufacturer's performance statistics on a number of them before making a purchase decision. Another possible source of information would be a "hardcore" plumbing supply house, rather than a home store.


For more information, please read the EREN article on tankless water heaters by clicking HERE!

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