What is an Electric Tankless Water Heater?

wiseGEEK Writer

An electric tankless water heater is a water heater powered by electricity that heats water without using a tank reservoir. They are several types available including those that service whole houses, those used in industrial applications and water heaters that are point of service and located right near the source where a person will require water, such as a shower or sink. This form of water heating has been popular in certain countries for a long time, but has been less preferred to heat water in the US. This is changing, as one of the advantages of this type of heating is it can save money on water heating costs, particularly on standby losses, the amount of energy that goes into heating water in a tank even when no one requires it.

A tankless water heater provides hot water on demand.
A tankless water heater provides hot water on demand.

There are different models and many makers of electric tankless water heater styles. There are also ones that use propane or gas instead of an electric heat source. In many cases, gas or propane ones may be more efficient, especially if a person wants to install a whole house water heater. Depending on heating needs, people may need to have a fairly significant source of power, and this might require changing wiring. More power is needed to heat water that begins colder, which means people will require different models depending on where they live and the average water temperature.

A propane tank used to power a water heater.
A propane tank used to power a water heater.

Even with extra demands on power, an electric tankless water heater may be a more efficient means of heating water than is an electric or gas water heater with a tank. It’s somewhat unclear whether they are equally efficient in conserving water. When most people use the water heater with a tank, a shower or bath can only last so long before the water gets cold, and the new tank of water won’t be adequately heated for a while, which often ends people’s enthusiasm for longer showers.

With the electric tankless water heater, provided the heater heats enough water quickly for things like showers or baths, there is an unlimited supply, and that might encourage people to use more water and take longer showers. Another issue is that it can take time before water starts to heat. Demand has to occur (turning on the faucet) before water gets heated. This may mean waiting with the water running for a few seconds to a minute before water is the desired temperature.

If people are interested in purchasing an electric tankless water heater, they really have to track water use. If expectation is that people can run the dishwasher, and take showers or do the laundry at the same time, a larger model will be needed. It’s smart to consider the highest need situations required in a house, since, buying one too small may mean hot water is in low supply when these situations occur.

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