What Is a Tankless Water Heater?

A tankless water heater provides hot water only when you need it. The appliance does not need to heat a considerable amount of water then store it in a tank. It eliminates the unnecessary use of electricity thus reducing your overall monthly bill.

How does a tankless water heater work?

A conventional water heater commonly heats up a predetermined amount of water and stores it in the attached tank. A storage compartment, such as a tank, has a fixed capacity which may not provide an adequate supply of hot water when you need it.

In such case, you will need to turn on the appliance again and wait until the entire heating-up processes are done. The conventional type also uses a considerable amount of energy. If you need a great supply of hot water very often, this old-fashioned appliance is not a money-saving one.

Tankless water heater is simply the opposite of the conventional type. It does not need a tank, but it is able to supply hot water as easy as it can provide cold water. When you turn it on, cold water travels through a heating element which is powered by either gas or electric energy.

Theoretically, it provides a limitless amount of hot water almost anytime. At normal condition, a large tankless water heater delivers 7.6 – 15.2 liters (2 – 5 gallons) per minute. The smaller appliance may not supply a sufficient amount, but you can install two or more heaters in some places. There is also a whole-house type which will basically provide hot water for almost all water-related appliances in the house.

Energy Source

Tankless water heater is divided into two categories based on power source, which are gas and electric. Both basically use the same heating mechanism.

1. Electric tankless water heater

Electric tankless water heater is easy to install and is available in various sizes (for example Eccotemp L5). The most important things to consider when purchasing the electric type are voltage, amperage, and circuit breaker. There are some different voltage specifications including 277V, 240V, 220V, 208V, 120V, and 110V.

You should also pay attention to the amp draw of the unit. Please only purchase a unit that is compatible with your overall electrical installation. If you cannot support the amp draw of the water heater, your electrical installation may fail to supply other electronic devices in your house.

Electric tankless water heater is actually easy to install, but you should consult an electrician to make sure that everything will run properly.

2. Gas tankless water heater

Gas tankless water heater is very difficult to install. It is recommended that you hire a professional to handle the entire installation procedures.

There are many things to adjust such as gas line, venting accessories, and electric connections. In other words, everything needs to be properly configured in order to prevent gas leak.


Tankless water heater is energy-efficient appliance yet it can supply literally limitless amount of hot water almost anytime. It is powered by either gas or electric, so it needs to be properly installed. The price of a tank water heater can be less expensive compared to its tankless counterpart, but tankless is more efficient in the long run.