Do Electric Tankless Water Heaters Need to Be Vented?


If you are not familiar with electric tankless water heaters, you may wonder if they need to be vented just like gas tankless water heaters do. Since I'm quite familiar with electric tankless water heaters, I'll explain.

Electric tankless water heaters do not need to be vented because they do not produce exhaust gas. Electric tankless water heaters use electric resistance heaters to produce hot water. They don't burn fuel to generate hot water and thus, they don't need to be vented.

Some people are curious about why there is no vent on top of electric tankless water heaters. Understanding how electric tankless water heaters work will provide more insights.

How Electric Tankless Water Heaters Work?

Electric tankless water heaters don't need to be vented because they don't produce any exhaust gas as a result of fuel burning. They simply use electric resistance heaters to heat water and produce hot water.

Electric Tankless Water Heater Working Diagram

An electric tankless water heater can have one or more heating coils where the water heating process takes place depending on its size or capacity.

The incoming cold water enters the electric tankless water heater and activates the flow sensor. Then, the control board detects the water flow and power up the heating coil.

The heating coil is an electric resistance heater. It's like your electric space heater. It turns red and hot just after a few seconds of getting the power supply thereby heating the water.

As the cold water passes through the heating coil, its temperature quickly raises to the target hot water temperature which is usually around 140°F (60°C).

Just before the hot water goes out of the water heater, a thermistor (temperature sensor) picks up the water temperature in real-time and feedback to the control board.

The control board will cross-check the hot water temperature with the temperature set point to make sure that the hot water temperature does not go beyond the temperature set point.

Furthermore, the thermal cut-off acts as the final safety measure in case the thermistor and the control board failed to act due to a malfunction.

With all of the control devices in place, the hot water temperature will not go beyond 140°F (60°C). Hence, steam will never be produced and therefore, a vent is not required.

Do Electric Tankless Water Heaters Need to Be Vented?

Electric tankless water heaters do not need to be vented for exhaust gas. However, you should not put them in a cramp and hot place.

A typical electric tankless water heater has one or more control boards. As we all know that electronic control boards are prone to fail if the ambient temperature gets too high.

So, placing an electric tankless water heater in the bathroom, the basement, the garage or even above the ceiling is fine. But, I wouldn't recommend you put it in the attic as it can get really hot up there. Not very good for any electronics.

Where to Put an Electric Tankless Water Heater?

You can basically put an electric tankless water heater anywhere indoors but not outdoor. Electric tankless water heaters mostly can't withstand the weather.

Nonetheless, it is best to put an electric tankless water heater as close to the hot water tap as possible to minimize energy losses and reduce hot water waiting time.

In my previous water heater projects, we always install them above the ceiling. However, it was due to the special feature offered. Usually, home electric tankless water heaters are installed below the ceiling in the bathroom.


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Yu Chang Zhen

I enjoy working on air conditioners and ventilation fans because Malaysia is a very hot country.

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