How to Choose the Best Electric Tankless Water Heater

If you’re considering a new water heater for your home, a tankless model could save you cold cash and cold showers. Choosing the best tankless water heater means weighing the costs of the heater, the installation, and your utilities against your home’s demand for hot water.

Since choosing the best water heater can make such an impact in your home, it’s important to know what to look for. Keep reading to make an informed decision, learn how an electric tankless water heater works, and what the pros and cons of installing one in your home are.

How Does A Tankless Water Heater Work?

Tankless water heaters come in two types: gas powered and electric. We’ll be focusing on the electric variety which run via a properly installed power supply and waterline. Gas heaters require a more complex and costly gas line with venting.

Tankless water heaters are also called “demand-type heaters” or “instantaneous water heaters” because they provide an instant and continuous supply of hot water. How is this sorcery achieved?

When you turn on a hot water faucet or one of your appliances (such as a dishwasher or washing machine) calls for hot water, cold water from your waterline travels into a tankless suitcase-sized unit. A flow sensor detects the demand for hot water and turns the unit on. The water passes through a series of electric heating coils that heat the water on-the-spot. These coils automatically turn off when the need for hot water is met. Because power is only used while water is being heated, it is a very efficient means to heat water in your home.

What Are the Benefits of an Electric Tankless Water Heater?

Have you ever stood outside the bathroom door wondering if there would be enough hot water left when it was your turn to shower?

Changing out your old storage-style water heater for a tankless model can bring many benefits to your home including:

  • More hot water
  • Better efficiency
  • Lower energy bills
  • Longer life
  • Easier installation and maintenance

More hot water & better efficiency

It is estimated that the average American household uses 64 gallons of hot water a day and spends $400-$600 per year to heat it. It is your second biggest utility expense. Tankless electric water heaters are 8%-34% more efficient than their storage counterparts. This could translate to significant savings depending on your water usage.

Hot water on-demand & lower energy bills

Because tankless heaters work on demand, there is always hot water. Because there is no standby energy loss to keep a tank of water hot, they use less electricity.

Longer life and easier maintenance

Tankless water heaters also outlive water heater tanks by 5-10 years. With proper installation and maintenance, expect a tankless unit to last over 20 years. If it does break down, parts are cheap and repairs are usually easy. Over time you’ll save lots of money.

What Are the Cons of an Electric Tankless Water Heater?

There aren’t many downsides to electric water heaters, but you should carefully consider each of them before deciding which water heater is best for your home. The biggest reasons why you might not use a tankless water heater include:

  • Cost
  • Water use
  • Climate
  • Flow rate


Cost vs water need will be your biggest consideration. Tankless water heaters tend to be more expensive. They make up for this in longer life and greater efficiency. They are easy to install but factor in the price of the plumbing and electrical work required. You should hire a certified technician perform the installation for you to maximize its efficiency.

Water use & flow rate

The biggest shortcoming of a tankless heater is its ability to provide continuous hot water to multiple locations. You may find that taking a shower while the washing machine is running to be a problem. The average water flow rate for a tankless water heater is 2-5 gallons of hot water/minute. For comparison, here’s how much hot water each uses:

  • Bathroom faucet: .5-1.5 gal./minute
  • Kitchen faucet: 1-2.5 gal./minute
  • Shower: 1-2 gal/minute
  • Washing machine: 1.5-3/minute

If you have several people in your home–perhaps teenagers who like long showers—you may find that a tankless water heater has difficulty keeping everyone in hot water. The two ways around this are to not draw hot water to different destinations at the same time or to install multiple point-of-use heaters to meet individual needs. For example: put one unit in the bathroom and one in the kitchen. Because electric heaters don’t need to be vented, you can install them anywhere.


Climate is also a factor. In a colder climate like Minnesota, our ground water temperatures average around 42 degrees. Compare this with Florida, where the average is 71-77 degrees, and it’s easy to see why your water heater will need more energy to heat your water. You’ll need a water heater that can produce that temperature rise.

Which Electric Tankless Water Heater Right for My Home?

An electric tankless water heater might be a great investment for your home. They have several advantages over a gas unit as they’re:

  • Less expensive
  • Easier to install
  • Comparative in flow rates
  • Greenhouse emission free
  • Require minimal maintenance

To choose the proper heater for your home, take each of the following considerations into account:

Flow rate

Consider the flow rate your home requires and the ground temperature rise (the degree change between ground water and hot water). Specifications on tankless heaters are often written like this:

Flow Rate @ 35F Rise (gallons/min): 5.27

This means that the unit described can produce 5.27 gallons of hot water/minute at a temperature increase of 35 degrees.

Temperature & flow controls

You’ll also want to consider the features available on your heater. The biggest variable is the amount of temperature control you have. Models range from simple on/off control to thermostats that automatically adjust for the incoming water temperature.

A more advanced model like those in the Stiebel Eltron Tempra line have modulating technology that constantly monitors the incoming water flow and adjusts accordingly for greater efficiency are more consistent hot water. Reading a few tankless water heaters reviews will give you a better idea of what’s available.

Electrical demands

Finally, you will need to make sure your home’s electrical meets the needs of your heating unit. On demand heaters use more power and require 120-160 amps to power the heating coils.

A certified electrician can upgrade your home’s electrical service and install the proper supply line from your electrical panel to your new water heater. The good news is that once you set up your home for an electric tankless heater, installing the next one will be much easier and cheaper.

Certified Twin Cities Electricians to Install Your Electric Water Heater

A new electric tankless water heater should supply your home with heated water for the next 20 years. You can trust us to install your heater quickly and properly to ensure it exceeds that expectation and doesn’t leave you in – ahem- hot water. Contact the experts at EarlyBird today and let us help you choose the best electric tankless water heater for your home.