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Stiebel Eltron DHC-E 8-10

Should I Buy a Tankless Water Heater?

Although tankless water heaters have been a staple in Europe for decades; their popularity in the US is a recent phenomenon. Tankless water heater sales have skyrocketed in recent years due to the lowered costs, heightened efficiency, pronounced longevity and economical size of these ‘always off’, ‘on demand’ units. Using either electricity or gas, these tankless wonders eliminate wasted energy used to heat water on ‘standby’. They are tiny enough to be installed in garages, attics, crawl spaces or even outdoors with the correct installation and protection. Fuel use in some cases is slashed by up to 50%, softening the blow to the environment as well as your pocketbook. Tankless options last 20 to 30 years while their tank counterparts are more likely to develop toxic buildup and may need to be replaced after just six to ten years. Despite these attractive features, there are a few drawbacks worth mentioning. Tankless water heaters often struggle to supply adequate flow under heavy usage conditions. If three people are showering while another washes dishes and a fifth does the laundry, a tankless heater may not be able to meet your needs without costly upgrades to wiring or gas ducts. There’s also the possibility that with the seemingly inexhaustible amounts of hot water and no fear of the ‘cold water sandwich’, tankless users may end up inadvertently using more energy than they were before.

How do they work?

Tankless water heaters work through a combination of heat sensors and computer chips that adjust the water flow according to your demand. The firing rate is sequenced to supply just enough hot water to fill a sink for instance, if that is the fixture you’re working with. Thus only the fuel needed to accomplish this limited task is burned. There is some lag time as the cold water from the pipes comes up from the ground and enters the tankless heating mechanism, but this is minimal as often the compact tankless unit can be situated right below or nearby the fixture it is servicing.

How to choose the best model for your needs:

Point-of-use electrical tankless water heaters are best for small outputs, whereas centralized ‘whole-house’ gas tankless units will better serve a demand for high water flow in a large family, business or hotel. As a general point of reference, a tankless water heater can comfortably produce about four simultaneous showers’ worth of water at any given time. Above that, you will need to begin looking at multiple installations and combination plans. Electric tankless options will cost less than their gas counterpoints, and gas tankless heaters may require ventilation upgrades and higher maintenance expenditures. Environmental factors will also play a part: in regions where electricity is produced through windmills, nuclear power plants and hydro-electric generators, an electric tankless heater is a great earth-friendly choice for your home.


Tankless water heaters range from $500 to $1500, but lowered utility bills create a huge incentive for the cost-conscious consumer. On the other hand, a home may need upgraded ventilation systems, electrical outlets or new pipes, all of which can increase the cost of installation for your tankless system. When you take into consideration the tankless units’ longevity (they last 10 years longer than a regular tank heater on average) and reduced impact on the environment, you can begin to weigh the costs on a long term basis and make an informed decision.


Gas tankless heaters should be inspected at least once a year by a qualified technician to make sure they meet safety and ventilation requirements. Left unchecked, toxic buildup can slow down the machine and even damage it. Electrical units are a bit easier to maintain and troubleshoot. Naturally installing either type of tankless unit outdoors will require greater upkeep in climates prone to bad weather, snow and rain.

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