Electric Hot Water Heaters
Reviews & Buying Guide

Review of the electric hot water heaters for residential water heating; types, popular brands, advantages, disadvantages, main parts, and how to select the right size and model.

Almost every manufacturer of water heaters in North America offers variety of the electric units, which are different in type and size; small like point-of-use or Lowboy, medium size like tankless or Table Top and big tank-type used for commercial and residential domestic water and radiant heating.

Selecting electric hot water heater -
Things to consider

Choose type

Electric water heaters are designed as large conventional, cylindrical storage tank-type and small tankless. While storage tank type is more popular for the whole-house water heating, small tankless are used mainly for point-of-use service, while bigger ones are able to provide hot water for more than one fixture.

Tank-type

Marathon electric water heatersMarathon tank

Electric tank-type water heaters are very popular type due to its proven technology and reliability. This type has very simple design; tank, surrounded by the foam installation and one or two heating elements. These are available in capacities from few gallons to over 100. For the best models, look for those with longer warranty, which is usually 12 years, have Incoloy heating elements and protection against dry-fire. The powered anode or commercial grade one is a preference, including a special dip tube for self-cleaning and reduced sediment build-up.

One of these top rated models is Marathon 50-gal from Rheem. Marathon comes with great features such as the non-metalic tank - so no corrosion, leaking and rusty water, also no need for the anode rod, used to protect metal tanks. The warranty is limited lifetime.

Another model, Westinghouse 80 gal., is the best selling on Amazon.com, and one of the features that stands out is the stainless steel tank that also provides limited lifetime warranty.

Tankless

Ecosmart electric tankless water heaterEcosmart tankless

Electric tankless water heaters are the favorite type of many homeowners, and this is why; small and compact, provide hot water on demand and in endless supply, and with the great efficiency of close to 99%. Installed mostly under the sink, electric tankless delivers water instantaneous to one or more fixtures.

For example, one the best models,  Tempra Plus 24, from German manufacturer Stiebel Eltron, comes with the advanced engineering and smart microprocessor, so hot water is always delivered with the steady temperature even if the flow varies.

And looking at the online store Amazon.com, EcoSmart ECO 27 is the best selling model. The reasons are; features such as self-modulating technology, 27kW of power and up to 6 gallons hot water delivery (enough for homes with up to 5 fixtures), reliability, and limited lifetime warranty

Heat pumps

GE heat pumpGE heat pump

Heat pumps, also known as hybrid, are the most efficient electric water heaters and the only electric type that is eligible for Energy Star, government and utility company rebates/incentives.

This 80-gal heat pump from GE is one of the models recommended by hundreds of homeowners and builders; it comes with the high 67 gallons First Hour Delivery and ultra energy efficiency of around 3 (three times more than standard type, and provides savings up to $490 in households with 3-4 family members.

Basics to consider

When selecting a new electric water heater, consider the following:

  • Hot water needs of your family (household).
  • Hot water delivery capacity (recovery rate and First Hour Rating).
  • Storage volume.
  • Energy efficiency (look for the lower standby loss rating).
  • Purchase and installation costs.

Advantages

  • Four different types; tank-type, tankless, heat pumps and in conjunction with the solar.
  • Even with the low recovery rate, the advantage is high tank capacity.
  • Easy to install.
  • Can be installed in many areas of a home.
  • Can be installed close to the actual point-of-use.
  • Various sizes and models.
  • No venting needed, there are no exhaust gases.
  • The cost is significantly lower than gas heaters.
  • Longer service life.
  • Energy efficiency goes to 99% for standard type and over 2.5 on heat pumps.
  • Electricity reaches more households than gas.
  • Electric tankless water heaters are one third of the size than gas heating systems.
  • Very little maintenance needed, easy to clean.
  • Much easier to diagnose the problem, troubleshoot and repair.
  • They are safe.

Disadvantages

  • Expensive to operate, electricity is more expensive than gas.
  • Low recovery rate.
  • Electric tankless water heaters are high amperage devices and when the hot water is used during the peak times its operating cost increases.
  • Even with the lower cost for installation, you have to consider an adequate electrical supply, to support this high output hot water heating appliance.
  • The biggest problem with electric hot water heaters is that they lose heat through the surface of the tank, also known as standby heat loss.
  • They fall into the category of water heaters with low recovery rates (the lowest actually) meaning that it takes longer to heat the water.
  • Solution for this problem is to cover them with a specially designed insulation blanket or a "jacket".

Main parts

  • Cylindrical storage tank holds the water. Typical sizes for residential electrical hot water heaters are 40, 50, 60 and 80 gallons.
  • To keep the rust out of the unit, steel tank has a bonded glass liner.
  • Insulation - helps to keep the heat inside the tank longer.
  • Cold water inlet and hot water outlet, or pipes.
  • Thermostats to control the water temperature inside the tank.
  • Heating elements to heat the water, usually two of them, upper and lower.
  • Drain valve that allows you to drain the tank.
  • Temperature and pressure relief valve (TPR) - safety feature.
  • Sacrificial anode rod - prevents corroding. Some models have the non-sacrificial powered anode.

How electric water heater works

Water heating process in tank-type electrical hot water heaters is very simple. There are usually two heating elements, submerged inside the water (immersion-type), one in the middle of the tank and one at the bottom, and two thermostats, one for each heater.

  • Cold water enters the tank heater through the dip tube and fills it from bottom up.
  • The top thermostat which is pressed against the tank, controls the upper heating element and turns it on when there is a need.
  • Cold water is becoming warmer and when it reaches the pre-set temperature the power is switched from the upper to the lower heating element.
  • Now, the bottom thermostat, which controls the lower heating element, turns the element on until the water temperature reaches the pre-set value.
  • Safety device, high-limit switch, reacts if the water becomes too hot, cutting the power to heating elements.
  • Once you open the hot water tap, hot water is drawn from the top of the water tank, at the same time cold water enters the tank, drops the temperature that triggers the thermostat. The whole water heating process starts all over again.
  • If there is an excessive pressure in that tank, because of the high water temperature, another safety device called pressure relief valve opens to release some hot water and reduce the pressure.

Thermostat is a switch and it can sense a change in water temperature. The switch closes to allow current flow and it opens when the temperature of hot water reaches its preset limit.

The current passes through electrical-resistance heating elements, power is delivered and it heats the water to the correct pre-set temperature.

The heating elements continue to carry current until the thermostats are satisfied. These heating elements are very efficient, providing about 99% of the available heat to the surrounding water.

On some tanks the thermostat has a mark showing a maximum temperature and where to set the temperature that provides energy savings and scald protection.

Money saving tips:

To reduce the heat loss through the bottom of the electric water tank heater, place the tank over a thick layer of firm thermal insulation to reduce the heat loss.

Reducing the temperature setting by 10 degrees F you can save between 2-5% of your electricity costs.

Insulate the water pipe so as the heater with the insulation blanket.

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