Electric Water Heaters
Buying Guide

A review of the electric water heaters for residential whole-house and point-of-use water heating, with the focus on tank-type and tankless heaters. Find out how electric models work, about main components, manufacturers and are they a good investment or not.



Electric hot water heaters with the storage tank are the most popular type in US and Canada. They are big, heavy, but reliable. There is a variety of types such as the conventional tall, medium or short, Lowboy, Tabletop, where 50-gallons heater is the most popular. Users and plumbers love this type, because electric heaters are simple, easy to operate, service and troubleshoot, no venting is required, can be used in majority of homes and have low price.

Tankless electric water heaters are small, wall-hanging, under-sink type and provide hot water only when there is a demand. Most of the time they are used at the point of service.

Heat pumps or hybrid heaters are very efficient (two times more efficient than standard type) and with the energy factor of two or more they are Energy Star compliant and eligible for tax credits and rebates. Heat pumps are great for the attic, garage and basement installation. It is the favorite type of those homeowners who are looking to go "green". The most popular are AO Smith, GE GeoSpring and Rheem.

Electric water tank heaters review

Main components

The following components are used in most of the traditional type heaters:

How electric water tank heater works

marathon electric water tank heaterConventional electric water heaters utilize one or two heating elements (lower and upper) for water heating. As the heating elements are fully immersed, they are able to transfer more than 90% (even 99%) of the heat.

Either the tap is open or not, water inside the tank is being heated and kept at the pre-set temperature.

Cold water from the home plumbing fills the tank through the dip tube, which is submerged almost to the bottom of the tank.

One of the heating elements is turned ON when the thermostat senses that the temperature of water is below the set value. Every heating element carries the thermostat which is mounted against the tank surface.

When the hot water tap is open, hot water from the top of the tank is drawn, and since the level drops, fresh water gets inside the tank. The lower temperature initiates the heating elements to heat the water to the set value. Once it reaches the set value the thermostat turns the heating element OFF waiting for another "call".

Electric hot water heaters are equipped with the safety elements, such as the high limit switch that prevents water from boiling or reaching the temperatures over the given on the thermostat, and in the case if the thermostat fails.

Popular manufacturers

Electric tankless Models

How electric tankless water heater works

electric tankless water heater from Stiebel EltronElectric water heaters with the tankless technology heat the water on demand. They don't utilize the tank, so they are small and most of the time are wall hanging. Tankless models produce an endless hot water and only when there is a demand. Great example is Stiebel Eltron and its popular model Tempra, DHC and DHC-E models.

When there is a "call" for hot water (the tap is open) cold water passes over the heating element and is heated instantaneously. Based on its power, tankless water heater can supply one or more fixtures at the same time while working as the point-of-use or whole-house heater.

Popular manufacturers


  • Electric water heaters can be used in almost any home (in NA).

  • Easy to install and use. Less risk is involved.

  • No venting required.

  • The efficiency is higher than on gas models, it can go to up to 99%.

  • Simpler troubleshooting. They are almost maintenance-free.

  • Cheaper to buy and install.


When searching for the best electric water heaters look for the high efficient models. These units save energy, heat fast, but are not Energy Star compliant. Actually, none of the tank- or tankless-type heaters are eligible for government grants, unless they utilize the heat pump technology. Heat pumps are the only electric appliances that are Energy Star approved.



Pictures are courtesy of Amazon.com company

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