Electric Tankless Water Heater Buying Guide

    Electric Tankless Water Heater Buyers Guide

    In many ways electric tankless water heaters are under appreciated in the world of on-demand hot water. They offer many advantages over their gas fueled cousin, but frequently don't receive the credit they deserve. Although, they do have short comings, their versatility and superb energy efficiency make them hard to ignore.

    If you're considering purchasing a tankless system you owe it to yourself to take a close look at electric on-demand water heaters. Whether you're looking for a whole-house system or a point-of-use unit, there are many advantages that make these systems a great choice.

    How to Buy an Electric Tankless Water Heater

    How Does an Electric Tankless Water Heater Work?

    An electric tankless water heater works entirely differently than a gas unit. When a hot water tap within the house is opened, cold water enters the tankless unit. The electric heating elements fire-up and the water is heated as it passes thru several chambers. By the time the water leaves the tankless, it's hot and ready to serve the open tap within the house.  

    Unlike a traditional water heater, an electric on-demand system isn't limited by the size of it's tank.  In fact, in theory, a tankless water heater is capable of delivering a constant supply of hot water. However, they do have limitations.

    Each model is manufactured with the ability to deliver a specific flow rate, that is, the amount of hot water the unit is able to deliver under ideal circumstances. If you purchase a unit with a flow rate that's below your household's hot water needs, your unit will deliver lukewarm water! Purchasing the correct size unit (called sizing) is critical to your overall satisfaction.

    Terms to know when sizing a tankless water heater:
    • Flow Rate - The amount of water the tankless unit is capable of heating at any given time. The flow rate is measured in GPM (gallons per minute).
    • Temperature Rise - The difference between the incoming ground water temperature and the heated output temperature.

    For the most part, you can expect your system to produce a flow rate of 2 to 5 gallons of hot water per minute. But keep in mind that electric units tend to deliver a lower flow rate than gas fueled units. So, it's best to estimate on the lower side.

    If you know your needed flow rate and the temperature rise necessary to meet your family's hot water needs it's very easy to select the properly sized system. Our tankless water heater buyers guide gives you step-by-step directions on how to determine these numbers. 

    Electric Fueled Tankless Water Heaters

    Electric on-demand water heaters are generally less expensive to purchase and install than gas systems. However, they do require a great deal of electricity to operate and many homes aren't able to accommodate their energy demands. If an upgrade to the home's electrical system is necessary, the installation cost will significantly increase. 

    Here are a few things to consider when buying an electric tankless:

    Price and Installation

    • Electric units are significantly less expensive than gas systems. A quality electric tankless can be purchased for $500 to $700.
    • Many homes are not built to provide the electrical requirements these units need to operate. Installation expenses will significantly increase if an upgrade is needed to the home's electrical. 
    • Since exhaust gases are not produced, venting is not necessary.
    • Inexpensive installation unless the electrical system needs to be upgraded.
    • Since venting isn't necessary, an electric unit can be installed in many locations unavailable to a gas system. 


    • ​The simplistic design results in a longer service life.
    • Because of their simplistic design electric units are easier to troubleshoot, diagnose and repair.
    • Electric tankless systems are about a third the size of gas units.
    • Requires minimal maintenance.


    • Extremely energy efficient. Over 98% of the incoming electricity is used to heat the water. (A gas unit may peak in efficiency at 80-85%).
    • Requires a substantial amount of electricity to operate.
    • Capable of delivering up to 8 GPM of hot water. 
    • Since no greenhouse gases are produced, electric systems are environmentally friendly.

    Electricity as a Fuel

    The struggle between gas and electric tankless water heaters can be confusing. From a fuel source standpoint, electric units are far more efficient. They typically reach 99% efficiency ratings! However, they are more expensive to operate.

    Yes, you read that right. An electric tankless will be more expensive to operate than a gas unit, even though they are more efficient. This is because the current cost of electricity is higher than gas. 

    ​Consistently, electricity prices are more stable than gas prices, and undoubtedly fuel prices will fluctuate in the future. Most agree that the price of electricity will likely increase at a much slower pace.


    Your owner's manual will have the details for your specific unit's maintenance requirements. But electric tankless units require far less maintenance than gas units. The water inlet screen and the unit itself needs to be flushed periodically to keep them running in peek form. Other than that, there is very little else that needs to be done.

    Electric tankless water heaters have a very simplistic design which means they don't require much attention and frequently have a longer service life than gas units. With a little care, they'll provide years of loyal service.

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