Andrew Patterson

Electric tankless water heaters are small in size and almost instantaneous in heating water. The boiler in comparison with them is much more massive, and the water heats up much longer.

What Is Tankless Electric Water Heater?

First of all, tankless heater differs from the conventional boiler by the lack of storage. Water is heated only at the time of use. You can adjust the temperature of water heating by changing the pressure in the right direction. In addition, tankless heaters consume less electricity, because they do not spend it on maintaining the temperature. Due to its characteristics, the tankless water heater allows you to save space, electricity and time.

The water heater is a small box inside which a tubular heating element is placed. The water heater operates in the following way: water enters the device, and then flows into the compartment where the heating device is placed. Washing it, the water is gradually heated, and then supplied to the taps.

Expensive devices have a control panel with different sensors and timers. Low-cost models are equipped with a thermostat that allows you to set the heating temperature. Some devices do not have a control system — they work only in automatic mode.

To install an electric tankless water heater, a wire running separately from the panel is required. A switch capable of operating in automatic mode is also required. The wire should be of a strictly defined cross-section corresponding to the power of the selected water heater.

A sufficiently powerful network is required for the efficient tankless storage. Otherwise, you will have to choose a device which power does not exceed 8kW.

Types of Tankless Heaters

The electric tankless water heater can be of the following types:

• Forcing
• Free-flow

Forcing, or systematic ones, can be used in different conditions, i.e. from any tap that is in the house. Pressure water heaters are cut into hot and cold water pipes. Such devices have only outlet and inlet for water. The device is controlled by water pressure.

Free-flow are characterized by low power (up to 8 kW) and economical energy consumption. They work only from one water intake point. These heaters are suitable for shower or use in the summer houses. The maximum heating temperature is 30°C, which makes them useless for use in winter.

Such water heaters are used all year round only in warm regions where temperature fluctuations are not so significant.

The cost of such devices is usually low. Shower heads and faucets can be included in the package. If the water intake point is far from the heater, it is better to install another one near it — it will significantly save money.

As for manufacturers, such companies as Stiebel Eltron, EcoSmart, Atmor, Rheem, Bosch have proven themselves best in the US market. You can find out here reviews of best electric tankless water heaters from these manufacturers.

The Calculation of Heater Power and Selection Criteria

After determining the type of device, select the optimal power. To do this, the following simple method is suitable: the heater power (in kW) is divided by 8. The result is an approximate water flow rate per minute (in gallons), heated to 86°F.

For clarity, you can use this example. If the power of the attracted flow heater is 16 kW, the water consumption will be 16/8, that is, 2 gallons of water at a temperature of 86°F per minute. Knowing how many gallons of hot water you need per minute, you can easily pick up the heater with this formula.

If hot water is needed not only for the shower, but also at other spots, when choosing a heater you need to take into account the indicators of the most powerful spot. If you plan to simultaneously use water at these spots, the power of the heater should be increased at least 1.5 times.