How Does a Tankless Water Heater Work?

December 2, 2015

In recent years, there has been increased focus on installing tankless water heaters in homes because of their high level of energy efficiency. If you’re considering investing in one, it’s important to know how a tankless water heater works.

Tankless Water Heater Installation

How a Tank Storage Water Heater Works

Most homeowners in the Oklahoma City area probably have a tank storage water heater in their homes. These models heat several gallons of water at a time, using either electricity or gas. The hot water is then stored in a large tank until you need it. As it sits in the tank, the water cools and has to be reheated periodically. This means the heat source has to keep firing up. If the water in the tank is used up too quickly, your home will be out of hot water until more is heated up.

How a Tankless Water Heater Works

A tankless water heater, or on-demand heater, also uses electricity or gas as the heat source. Instead of heating a lot of water ahead of time, a tankless system heats water only as it’s being used. Inside a tankless water heater is a flow sensor that switches on the burner as cold water enters the heater. This burner warms up the heat exchanger. When you turn on a hot water faucet, the cold water flows around the heat exchanger and gets warmed up by direct heat transfer. When the water leaves the heater, it’s already at the pre-set temperature.

Benefits of a Tankless Water Heater

The most noticeable benefit of installing a tankless water heater is increased energy efficiency, because water is only heated as it’s needed. There’s also no standby energy being used to keep a tank of water heated to the desired temperature.

You’ll also never run out of hot water with a tankless water heater, so you’ll be able to enjoy a hot shower while the dishwasher and the washing machine are running, if you want to.

Tankless water heaters typically last longer than tank storage models, too. Tank storage water heaters typically need to be replaced every 10-15 years. Tankless versions do cost a little more up front, but you can expect them to last 20 years or more.