Buyer's Guide & Information

Best Electric Tankless Heaters For Consistent Hot Water

Never worry about running out of water again. These top-rated brands are energy efficient which will also save you money on water and electricity bills.

by PlumberAndy

Buyer's Guide & Information

Best Electric Tankless Heaters For Consistent Hot Water

Never worry about running out of water again. These top-rated brands are energy efficient which will also save you money on water and electricity bills.

by PlumberAndy

by PlumberAndy

Tankless water heaters are growing in popularity all over the world as consumers are looking for better options to heat their water in a fast and energy efficient manner.

According to Energy.gov, there are many advantages to owning one or several tankless water heaters. They state “For homes that use 41 gallons or less of hot water daily, demand water heaters can be 24%–34% more energy efficient than conventional storage tank water heaters. They can be 8%–14% more energy efficient for homes that use a lot of hot water -- around 86 gallons per day. You can achieve even greater energy savings of 27%–50% if you install a demand water heater at each hot water outlet.”

That’s a lot of energy saving! This article aims to help you find the best electric tankless water heater for your home, apartment, cabin or RV.

What are Electric Tankless Water Heaters?

Tankless water heaters are made to provide hot water only when needed. Unlike regular water heaters, they don’t have a large supply of hot water at the ready waiting in a tank, but they can heat water quickly and are capable of heating from 2-5 gallons of hot water per minute. For this reason, they’re also known as on-demand water heaters or instantaneous water heaters.

Conventional water heaters have tanks ranging from 20 to 80 pounds and can take up a relatively large amount of space within your home. Tankless water heaters, on the other hand, are small wall-mounted appliances that might often be mistaken for a circuit box. Electric tankless heaters are about half the size of gas-powered tankless heaters.

Stiebel Eltron Tankless Electric

Electric Vs Gas Tankless Hot Water Systems

Many household appliances can be hooked up to either electric or gas, and tankless water heaters are no exception. The two versions, however, are slightly different. Electric tankless water heaters are smaller units and are easier to install.

Gas models (either propane or natural gas) require larger units to accommodate their pilot light system and they also require additional ventilation to an outdoor area. This is to protect you from over exposure to carbon monoxide. Because of this larger size and additional setup, gas tankless hot water systems are usually more expensive to install.

It has long been argued that overall gas models were cheaper to run, but our research has shown us that the price difference is marginal, especially when you consider energy efficiency. Electric tankless versions can be up to 99% energy efficient, whereas most gas tankless heaters are only 80-85% energy efficient and release greenhouse gases into the environment.

For more ways to compare electric vs gas tankless hot water systems, check out this handy chart by Go Tankless.


Hot Water Needs: Whole House or Small System

Whole House

When it comes to installing tankless water heaters in your home, you have the option to purchase a whole house unit or to buy several units to cover the different areas in which you use hot water.

The choice will depend on how much hot water you use at any given time and will be mostly up to your preference. If you and your spouse live alone and don’t usually do laundry, run the dishwasher, and shower at the same time you might choose to have one whole house system.

If you have several children and need to be using several water sources at once, you might choose to have different zone units installed.

Eemax Type of Water Heater

Small System

Small tankless hot water systems are also known as point-of-use systems because they only provide hot water to one area (for example, under a kitchen sink).

These units are a great option for small cabins, RVs, campers, and even boats! You can install a small tankless hot water heater anywhere you need hot water for a specific use.


Buyers Guide: Electric Tankless Water Heaters

Indoor Vs Outdoor

Electric tankless water heaters can be easily installed outdoors or indoors. Because they don’t take up much space, you will probably decide on installation based on where plumbing will be easiest.

If you’re replacing a conventional hot water heater, for instance, it may be easiest to install your new tankless heater near the connection for that.

Outdoor tankless water heaters are made to stand up to the elements of rain and wind and weather. However, it’s important to note that you need to be careful if you live in an area with freezing temperatures.

Although the systems do have freeze protection (and often have little heaters to keep them warm), in the event of a power outage you will have to take extra measures to drain your unit and keep it from freezing.

Size & Weight

Most electric tankless water heaters are fairly small in size and weigh between only 15 and 20 lbs. Their size makes them ideal for installing in areas that are too small for convention water heaters, or if you’d just like to create some more floor space.

And because electric tankless models don’t require ventilation, you can easily install them nearby any hot/cold water supply within your home.

Certification

WaterSense Promotion Label

One of the items you’ll notice is missing on an electric tankless hot water heater’s data is an Energy Star Certification. It’s not because the models are not energy efficient or that they don’t deserve certification, but rather simply that the category does not yet exist.

For gas powered tankless water heaters, however, there is a category of Energy Star Certified products. This article by Eemax does a good job explaining why you won’t find Energy Star Certifications on electric models, and why it’s not necessarily a bad thing.

There are, however, a few other certifications that you might come across, including Watersense which according to the EPA means WaterSense labelled products meet EPA's specifications for water efficiency and performance, and are backed by independent, third-party certification.

Voltage

It’s important to consider the voltage of an electric tankless water heater because you need to know if the product that you’re looking at will work with your current electrical system.

This article by Howell-Oregon Electrical Cooperative explains that most electrical tankless systems require you to upgrade your electrical system, and why this can be a costly investment.

Energy Efficiency

Complete energy efficiency is determined by each model, but overall electric tankless water heaters can be up to 99% energy efficient and about 24%-34% more energy efficient than their conventional water heater counterparts.

Installing several electric tankless water heaters within your home in different heating zones can make them even more energy efficient.

GPM (gallons per minute)

GPM is the number in which flow is output from the electric tankless water heater. The number we list in each model’s chart below represents the maximum output when the electric tankless water heater is heating one water element.

For example, a heater that has a GPM of 4 will produce 4 gallons of hot water per minute when in use for one shower. If two showers are being used, they will have to share the flow, thus making it less than 4 GPM.

Kilowatts (kW)

1 kilowatt is the metric unit that is equal to 1,000 watts. So, 9 kW = 9,000 watts, 13 kW = 13,000 watts, etc. Wattage tells us how much power an appliance can put out in an hour’s time.

In terms of tankless water heaters, the higher the kW the more power the appliance will have, but also the more energy it will use. You can figure out your kW needs by assessing how many hot water appliances your home has and how often they will be in use.

Temperature Range

Most of the units that we look at in this article have a temperature range from about 80F to 140F. This is a pretty universal range for all hot water heaters.

Given that most hot showers average at about 105F, you can rest assured that in this range that you’ll have just the right temperature all the time while showering and that your dishwasher is getting hot enough to sanitize your dishes.

Price Vs Usage

Electric tankless water heaters are more money up front without question, but their energy efficiency means they have the capacity to save you money over time. According to Energy.gov, tankless heaters have double the lifespan of conventional tank heaters.

Over the lifetime of the product, a tankless water heater is estimated to save you $1,800 – almost quadruple what you would save with a high-efficiency conventional water heater.

Warranty

When purchasing an electric tankless water heater, it’s important to understand each products warranty policies. Some products are completely covered, whereas others are only covered for leaks or parts and you will still need to pay for the labor to have the unit fixed.

And to make sure that you don’t unknowingly break the terms of your warranty, we always recommend that you have the product installed by a professional and keep a paper trail of the transaction.

Warranty

8 Best Electric Tankless Water Heaters Reviewed

1. Stiebel Eltron Tempra Plus 24

Best Whole House Option

GPM

4.68 GPM

kW

24 kW

Weight

20.5 lbs

Voltage

240 V

Temp Range

86F – 140F

Certification

ANSI/UL Std. 499

The Stiebel Eltron 24 Tempra Plus is the best whole house electric tankless water heater on the market. One of the things that’s extraordinarily helpful is that Stiebel Eltron provides an easy sizing guide so that you can see which tankless water heater is right for your home.

You can easily see how many hot water appliances you can run at a time and how the GPM (gallons per minute) will be affected.

They also take into consideration the temperature of the groundwater where you live, which I feel is critical information. I was surprised by the vast difference in groundwater temperature from where I lived in Michigan to my new home in North Carolina.

The Tempra Plus 24 is a small unit that does not require any ventilation, making it easy to install. It has a silent operation and really does live up to its seemingly endless supply of hot water.

But I think the factor that really had me sold on this model was the warranty. Stiebel Eltron has a 7-year warranty for leakage and a 3-year warranty for parts. There’s a lot of confidence and knowledge that has gone into this appliance and it’s something I can feel good about using in my home (and no more fighting over the hot water!)

"The best," says reviewer Jose from Lowe's. "Easily to install and hot water in seconds so far so good."

Pros
  • Easy installation / no ventilation required
  • Silent Operation
  • 99% energy efficient
  • Saves 15-25% on energy bills
Cons
  • The decrease in pressure when two or three showers are in use at once can be bothersome
  • If you have hard water where you live, you will need to consider purchasing a water filtration system to lengthen the life of your unit

2. EcoSmart ECO 11 

Best Small Electric Option

GPM

2.3 GPM

kW

13 kW

Weight

6.5 lbs

Voltage

240 V

Temp Range

Not Specified

Certification

Watersense, UL-499, ETL Listed

The EcoSmart ECO 11 is a rather small unit that is specified for point-of-use application, meaning that it would be hooked up to only one shower or maybe a shower/sink bathroom combo. Weighing in at just 6.5 lbs, we found this model to be the best small electric tankless water heater.

EcoSmart also offers a large range of sizes (up to 36 KW) that will fit any homes needs. We chose the focus on the smallest of the range in this review but any of the larger models are equally as good.

I love that the EcoSmart brand truly wants you to find the best product for your specific needs. With the ECO 11 model, they state that this unit will be best used in areas where the groundwater is 67F and above, making this the ideal model for people who live in Florida or southern California.

best electric tankless hot water heater

The graphic below shows that the ECO 11 will work in other ground temperatures, but that flow will be slightly compromised.

For example, at a ground temperature of 72F you will get 2.7 gallons per minute, whereas at a ground temperature of 42F you will only receive 1.4 gallons per minute.

The ECO 11 also makes a great option for RV use, especially if your RV is located primarily in the southern states.

To me, it would be worth compromising water flow when traveling to places where the groundwater is lower to know that I have an energy efficient product that I can depend on daily.

Cleaning and maintenance is accomplished with a Phillips screwdriver, no more pipe wrenches and fiberglass insulation to contend with. The unit is so small and lightweight that I actually carried it into the house under one arm, installed it and said nothing. Nobody knew that I'd done this until days later!”

Pros
  • Lightweight / Fits nearly anywhere
  • Saves up to 50% in water heating costs
  • Self-modulating technology will only use the energy needed to output your hot water
  • Limited Lifetime Warranty
Cons
  • Most suited for warmer climates where the groundwater is 67F or above
  • Only meant for 1-2 heating sources

3. Eemax EEM24018 

Best for Colder Climates

GPM

2.9 GPM

kW

18 kW

Weight

14.5 lbs

Voltage

250 V

Temp Range

80F – 140F

Certification

CSA Listed,ETL Listed

A lot of electric tankless water heaters have a difficult time working in colder climates, but the Eemax brand really seems to stand up to the test. The model we looked at (EEM24018) can easily heat one shower in cold climate, so northerners might benefit from owning several of these units for each of their showers.

However, in a warmer climate this Eemax model can heat up to four showers simultaneously! (Who even has four showers?) For that reason, we have listed this model as the best electric tankless water heater for colder climates.

The unit itself is a sleek blue model with a clean design and a digital display where you can set your hottest temperature. This is a great feature, especially for those of us with young children and the worry that they might scald themselves with hot water.

Another comforting fact is that Eemax is known for their top-notch customer service. Many reviewers with issues (such as flow, filter questions, etc) were able to get the help they needed quickly just by calling and speaking with customer service.

"Eemax is the #1 supplier of tankless water heater solutions. For over 25 years we’ve offered energy efficient, on demand hot water heaters for commercial applications, residential homes, and industrial safety applications. Our green, environmentally friendly water heaters offer the largest selection in the industry." - Eemax

Pros
  • Nice design
  • Can work for whole house or point-of-use
  • Works in both warm and cold climates
Cons
  • Only produces 2.9 GPM at best
  • Less efficient in colder climates

4. Stiebel Eltron 074055

Best Electric POU Heater

GPM

2

kW

7.2

Weight

5.3 lbs

Voltage

240 V

Temp Range

86F – 140F

Certification

Certified to ANSI/UL Std. 499

The Stiebel Eltron is the best point of use electric tankless water heater that we looked at.  At just over 5.3 lbs, this small unit would be ideal to install under a bathroom sink. Having hot water immediately just can’t be beaten!

The specific version we looked at, the DHC 8-2 could possibly be used for a shower but the highest volume GPM is only 2 so that might be a bit frustrating if you’re used to more water. Some reviewers found that albeit slow, the Stiebel Eltron was the best option for filling a bathtub as well. I guess they didn't mind waiting!

There were two things about this model that really caught my attention. First, Stiebel Eltron has a proprietary scald-guard on the system that will make sure that the hot water coming out is at a safe temperature, always.

Second, I was intrigued by the phrase “the design prevents Legionella bacteria growth.” When a did a little more research, I found that this bacterium is actually quite common in conventional water heaters that aren’t kept hot enough between uses and can make you quite ill. So, bonus points on that for sure!

Pros
  • Small unit can practically be installed anywhere
  • Proprietary scald-guard thermostat built-in
  • Unlimited and instant hot water at point-of-use
  • Prevents Legionella bacteria
Cons
  • Can only be used at one point
  • GPM relatively low / more ideal for sink than shower

5. iHeat Tankless S-9

Lightweight Model

GPM

2 GPM

kW

9 kW

Weight

7.5 lbs

Voltage

240 V

Temp Range

80F – 140F

Certification

ANSI Certified, CSA Certified

The iHeat Tankless S-9 is a lightweight stainless-steel model that can be installed almost anywhere. The company lists the S-9 as a point-of-use system made for warmer climates likes Florida and Arizona.

Even though it’s a point-of-use system, the company recommends the unit for several uses in these warmer climates (if they aren’t used simultaneously).

So, if you’re looking for a tankless electric water heater for your condo or small apartment in these warmer regions, the iHeat S-9 might be the perfect choice. If you have a larger home, one of their higher kilowatt models would suit you better.

My only concern with this model is that several reviewers have mentioned that this great product starts to break down after only one year and that customer service has very limited hours and is less than helpful.

A solid tankless water heater should last you for 15 years or more, so the jury is out on this one. It does come with a 3-year parts warranty if you’ll willing to try it for a while, but any labor costs will be on you.

Pros
  • Small unit can be installed nearly anywhere
  • Stainless steel waterproof box
  • Works great in warmer climates
  • Ideal for small condos or apartments
Cons
  • Users have complained works great for only one year
  • Not efficient for colder climates / only OK for moderate climates
  • Slightly more expensive than other point-of-use units

6. Sio Green IR30 

Best 1 GPM Option

GPM

1 GPM

kW

3.4 kW

Weight

6.4 lbs

Voltage

120 V

Temp Range

80F – 112F average

Certification

Not Specified

One of the things that immediately caught my attention regarding this Sio Green Electric Tankless Water Heater is that it has infrared heating elements.

To put it in the company’s own words, “Our tankless hot water electric heater will create heat without direct contact with metals, which will, in turn, prevent corrosion, limescale deposit and calcium buildup. As a result, you will have to spend $0 on maintenance, no replacement parts, no filter required.”

The Sio Green IR30 is meant as a “handwashing unit” – meaning that it will not stand up to the test of shower or washing machine use because it wasn’t built for that. It only has an output of 1 gallon per minute, which is plenty for handwashing and would make this an excellent choice for an RV or small cabin.

The main complaint from consumers is that they were not able to use their 2-year warranty when something went awry because they failed to register their product within the first 30 days (thus completely voiding the warranty). For this and for any unit it’s so important to read the fine print when bringing home a new product!

"This water heater is pretty amazing. It looks slick, and works very well. The internals look high quality and well made, and it heats water in my bathroom sink much faster than my now defunct element-based heater. The controls are easy, and the fact it shows you the temperature is really nice." - 5-Star Review

Pros
  • Budget-friendly product for one handwashing station
  • Comes with a full 2-year warranty with registration within 30 days of purchase
  • Infrared heating elements for less maintenance
Cons
  • Can only be used for sinks / not compatible with other appliances
  • Cannot be used where the groundwater is less than 62F

7. Dltsli Instant Water Heater

Best Budget Option

GPM

1.2 GPM

kW

5.5 kW 5 kW 4.5 kW 3.5 kW

Weight

3.5 lbs

Voltage

240 V

Temp Range

77F – 131F

Certification

Not Applicable

If you’re looking to install an electric tankless water heater in one small location like the sink of a bathroom, pool house, or outdoor workshop, then the Dltsli Instant is a smart choice that’s not only functional but also super budget friendly at under $100.

Unlike other small units though, the Dltsli Instant cannot be hooked up to run more than one item, even when used separately. If you want to run a shower and a sink in a bathroom, you would need to buy two units – which given the price might be worth it.

When I first came across the Dltsli unit, I didn’t think it was a tankless hot water heater at all because it’s so small! I honestly thought it was some kind of thermostat.

The unit has a sleek design and comes in a gold color. I was disappointed that it didn’t come in other colors (I prefer the stainless look), but it’s seriously so small and you will probably install it underneath a sink where no one is ever going to see it anyways. You really won’t find a better unit for the price.

Also worth mentioning is that unlike many of the other units we looked at, this one has four different kW power levels (within a small range) so you can best determine the needs for your sink or shower.

Pros
  • Budget-friendly option for point-of-use water heater
  • Small, sleek design weighs less than 3.5 lbs
  • Has four different kW power levels to customize your experience
Cons
  • Can only be hooked up to one appliance needing hot water
  • Does not get as hot as many other units
  • Does not come in any other colors than gold

8. EcoSmart 7.2 kW Booster

Best Water Booster

GPM

1.4 GPM

kW

7.2 kW

Weight

4.75 lbs

Voltage

240V

Temp Range

80F – 140F

Certification

Watersense, UL-499, ETL Listed

For those who currently have a working conventional water heater but are considering an upgrade to an electric tankless water heater, the EcoSmart Water Heater Booster might be a great first step.

Unlike the other models we’ve reviewed in this article, the EcoSmart Water Heater Booster is not a stand-alone tankless water heater. Instead, it is meant to literally “boost” your current full standing conventional water heater to create a seemingly endless supply of hot water.

"You're done with cold showers. With the new SmartBoost by EcoSmart, cold showers are a thing of the past. Enjoy hot water for almost twice as long so everyone in your family can take a hot shower, without rushing." - EcoSmart

This product would make a great option for homes with many teenagers taking turns showering in the mornings or lots of laundry to run. 

The EcoSmart Electric Water Heater Booster works by being installed on top of your existing water heater, and heating water as it comes through so that you aren’t limited to the supply in the tank.

Pros
  • Works with your existing conventional water heater to create and endless supply of hot water
  • Small unit takes up only a few inches of space atop of your water heater
  • Will not affect water flow or pressure
Cons
  • Does not work as a stand-alone tankless water heater
  • You will likely need to upgrade your circuitry to run both the hot water heater and the booster simultaneously


Frequently Asked Questions

How do you install an electric tankless water heater?

Most tankless water heater manufacturers agree that your new electric tankless water heater should be installed by a licensed plumber or electrician for safety reasons.

However, if you’re a pretty savvy DIY-er and know a thing or two about electrical circuits then the process is pretty straight forward. Here’s a YouTube video showing EcoSmart Tankless Electric Water Heater installation.

How much does it cost to install an electric tankless hot water system?

According to Home Advisor, the labor costs for the installation of an electric tankless hot water system will likely range from $100-$450, depending on the hourly rate of your licensed plumber.

What are the differences between tankless & tank hot water heaters?

See our chart below on some of the main differences between these two types of water heaters:

Tankless Hot Water Heater:
  • More Energy Efficient
  • Higher Initial Cost
  • Smaller Footprint within Home – Wall Mount
  • Overall Lifespan 20+ Years
  • Water Flow More Limited
  • Instant Hot Water / Unlimited Supply
Conventional Hot Water Heater:
  • Less Energy Efficient
  • Lower Initial Cost
  • Larger Footprint within Home – Tank ranging from 20-80 gallons
  • Overall Lifespan 8-12 Years
  • Greater Water Flow
  • Water Takes Time to Warm Up / Cools as Tank Becomes Depleted
How reliable are tankless water heaters?

As long as your electricity is working properly, your electric tankless water heater will be superbly reliable, and you will find that you never run out of hot water no many how many people have showered before you.

The units are constantly at work when you’re running your hot water supply. Using more than one shower or doing dishes/laundry simultaneously will decrease the water flow but the temperature should remain rather consistent.

How do I know which size to buy?

Each brand of electric tankless hot water heaters typically has a sizing guide (like this one from Eemax) to help you determine the right size for your home.

Unlike appliances like heaters, the size of your home will not matter as much as how many hot water locations you plan to use at a time. The sizing guide can walk you through this process to help you make the right choice for your current lifestyle.

Do I need an amp breaker?

You should always check to make sure that your electrical system can support the model of tankless water heater you desire. Say that your circuit breaker has 200 amps.

Maximum capacity for this would be 80% (or 160 amps) before the circuit becomes hot and becomes overloaded. If you’re looking at a model that requires 200 amps, you will need to upgrade to support the model and your other electrical units.


Conclusion

Though more expensive upfront than a conventional water heater (in terms of overall output), the energy efficiency and endless hot water supply are making electric tankless hot water heaters more appealing to the masses. For the best whole house electric tankless water heater, we recommend the Stiebel Eltron Tempra Plus 24.

That said though, we’ve also done the research to help you find the best electric tankless water heater for your own lifestyle, whether it be in an RV, a home, a small apartment, boat, cabin or anywhere!

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