Tankless water heaters, also called on-demand water heaters, have a number of significant advantages over storage tank water heaters, such as:
- An unending supply of wonderfully hot water, without a wait for recovery
- Potentially significant savings on utilities
- Substantial space savings
- Depending on your placement of tankless water heaters, you may have much more rapid access to hot water for your shower, etc.
The ultimate guide to best tankless ELECTRIC water heaters
High-demand: Stiebel Eltron Tempra Plus 36 kW Electric Indoor Tankless Water Heater
Medium-demand: EcoSmart ECO 27 Electric Tankless Water Heater
Low-demand: Rheem RTEX-13 240V Electric Tankless Water Heater
Best Seller: EcoSmart ECO 11 Electric Tankless Water Heater
Key factors to choose the best electric tankless water heater
When you have decided to install a tankless water heater, you then must choose whether that heater is powered by gas or electric. There may be many reasons you might want to choose a tankless gas water heater, but let us explore why an electric tankless water heater might be a better choice in some situations.
Reasons to consider a tankless electric water heater rather than gas:
- Your house may have access to electric utilities but not gas
- You may be replacing a previously installed electric tankless water heater
- Electricity may be cheaper in your area than gas
- You may want a point-of-use system to deliver hot water nearly instantly
- Electric tankless water heaters are often less expensive to purchase and install, the latter because venting is simpler or not required.
Our top pick Electric Tankless water heaters:
High Demand: Stiebel Eltron Tempra Plus 36 kW Electric Indoor Tankless Water Heater
Model: Stiebel Eltron Tempra Plus 36 kW Electric Indoor Tankless Water Heater
Dimensions: H-22.5”, W- 17.75″, D-10.75”
Weight: 19 lb
Flow rate: Minimum Flow Rate 0.77 GPM. Maximum Flow Rate 7.5 GPM at 72°F inlet temperature
Demand type: Moderately High-demand, most suitable for high-occupancy of 2-3 bathroom households or commercial application
Application: Centralized tankless water heater
The Stiebel Eltron Tempra Plus 36 kW tankless electric water heater is a high demand electric tankless water heater suitable for a larger house or for smaller commercial applications. Stiebel-Eltron is a German manufacturer which has been in business since 1924, and it has a well-earned reputation for well-designed, high quality water heating products. It is superbly engineered with a microprocessor controller and a patented feature to help maintain water temperature beyond normal flow rates.
Note that the manufacturer recommends 300A electric service. Please make sure your house/business has the appropriate level of electrical service or that you have budgeted for upgrading your service.
PROs:
- This high-demand flow rate is more than sufficient for most even larger houses
- The Stiebel Eltron Tempra Plus features a unique (and patented) Advanced Flow Control™ which maintains output water temperature over a greater range of usage by slightly reducing flow rate to each device in times of highest usage.
- Self-modulation ensures that the minimum amount of energy is used at all times by continually monitoring incoming water temperature, the flow rate of water through the heater, and the water temperature it produces. This information goes to the unit’s proprietary microprocessor control which engages the heating elements in stages, as efficiently as possible, to achieve the water temperature set on the front panel, always using the minimum amount of energy necessary to heat the water.
- Easy to use digital controls.
- Users report savings of at least 15% operational costs.
- 100% Copper heating chambers.
- Designed and manufactured for a long life of trouble free service.
- Space saving compact size
- Easy installation—requires no venting!
CON:
- Ensure that you have 300A electrical service available or that you have planned/budgeted for installing that service.
Tips for installations:
- Like all electric tankless water heaters (especially higher capacity units), make sure your electrical service is adequate. If not, you must add the cost of upgrading your electrical service to your total project cost.
- You likely will want to hire a licensed contractor to install this unit properly—although a number of home-owners have done successful self-installs if you are familiar with working with plumbing and electricity. Please get a permit and requisite inspections from your local building department.
Summary
If you want to replace an existing hot water heater with an electric tankless water heater for your whole house, this Stiebel Eltron Tempra Plus 36KW certainly merits your consideration. Stiebel Eltron is an extremely well respected brand from a nearly 100 year old German company. With its excellent warranty (7 years against leakage / 3 years against defects in workmanship & materials) and its product durability, you can count on having continuous hot water for many years to come. An energy saving tankless electric water heater can increase the value of your house while providing endless, instant hot water.
Advanced engineering and features yield a quality product. Its excellent warranty and easy installation make the Stiebel Eltron Tempra Plus 36 kW tankless electric water heater an excellent choice.
Medium Demand: EcoSmart ECO 27 Electric Tankless Water Heater
Model: EcoSmart ECO 27 Electric Tankless Water Heater
Dimensions: 17″ H x 17″ W x 3.625″ D
Weight: 14.7 lb
Flow rate: Minimum Flow Rate 0.3 GPM; Maximum Flow Rate 6.6 GPM with 77°F inlet temperature
Demand type: Moderately High-demand, most suitable for 2-3 bathroom household, or small commercial application
Application: Medium Demand centralized tankless water heater
The EcoSmart ECO 27 Electric Tankless Water Heater is an excellent medium demand instant water heater with Patented Self Modulating Technology that minimizes energy consumption while producing endless hot water. EcoSmart also has a limited lifetime warranty (if professionally installed), demonstrating its confidence in the reliability of the unit.
This tankless water heater has 3 separate heating elements. Each internal unit requires a separate, dedicated 240 volt 40 amp circuit, meaning it requires a total of three separate #8 wire 240 volt circuits. Please make sure your house/business has the appropriate level of electrical service for both the tankless water heater and other electrical consumption or that you have budgeted for upgrading your service. Typically, a house should have at least a 200A electrical service. It’s always best to consult your friendly neighborhood electrician.
PROs:
- This moderate to high-demand flow rate heater is more than sufficient for most even larger houses, typically supporting up to 4 simultaneous low-flow showers.
- Self-modulation ensures that the minimum amount of energy is used at all times by continually monitoring incoming water temperature, the flow rate of water through the heater, and the water temperature it produces. This information goes to the unit’s proprietary microprocessor control which engages the heating elements in stages, as efficiently as possible, to achieve the water temperature set on the front panel, always using the minimum amount of energy necessary to heat the water.
- Easy to use digital controls allow setting water temperature in 1° increments.
- Users report savings of up to 50% on operational costs.
- 100% Copper and Stainless Steel components
- Designed and manufactured for a long life of trouble free service with an excellent warranty
- Space saving compact size
- Easy installation—requires no venting!
CON:
- Ensure that you have at least a 200A electrical service available or you have planned/budgeted for installing that service.
Tips for installations:
- Like all electric tankless water heaters (especially higher capacity units), make sure your electrical service is adequate. If not, you must add the cost of upgrading your electrical service to your total project cost.
- You will want to hire a licensed contractor to install this unit properly and to ensure that your warranty is in force.
Tips for maintenance:
- The heating elements are easily removed from this water heater. You should periodically remove them and soak them in vinegar to remove any built up scale. If your water is quite hard, you should schedule this about every 6 months. The cost of maintenance is trivial compared to the cost of replacing parts due to neglected maintenance.
Summary
If you want to replace an existing whole house hot water heater (or install a water heater in new construction) with an electric tankless water heater, this EcoSmart ECO 27 Electric Tankless Water Heater should be on your radar screen. EcoSmart is a respected green products manufacturer, and this unit includes a limited lifetime. An energy saving tankless water heater that produces endless, instant hot water can be a great improvement to your home (and increase the value of your house).
This EcoSmart ECO 27 is a leading edge product with great energy efficiency. Its excellent warranty and easy installation make this electric tankless electric water heater an excellent choice for home use.
Low Demand: Rheem RTEX-13 240V Electric Tankless Water Heater
Model: Rheem RTEX-13 240V Electric Tankless Water Heater
Dimensions: 3.63” D x 12.63” H x 8.25” D
Weight: 8.5 lbs
Voltage : 240 volts
Kilowatts: 13 kW
Flow rate: 3.17GPM. It can manage two water-saver shower heads the same time, or a dishwasher and washing machine the same time.
Demand type: Low-demand, most suitable for low-occupancy of 1-2 persons household.
Application: Point-of-use tankless water heater or multiple applications
This Rheem RTEX-13 is a space-saving, indoor electric tankless water heater. It has a flow rate of 3.17 GPM, most applicable for low-demand usage or a single point-of-use. It can manage two water-saver shower heads the same time, or a dishwasher and washing machine concurrently.
Rheem is the largest manufacturer of water heating products in North America, and they have been in business since 1925. Rheem is well-known for its quality products and excellent product warranty. This Rheem RTEX-13 has Energy Star certification of 99.8% energy efficiency. It comes with five-year heating chamber and one-year parts limited warranty.
PROs:
- Modern and clean-line design
- Compact and spacing saving
- Digital temperature control from 80°F to 140°F (increments of 1°F)
- Easy installation – It comes with a 3-foot electric cable and 1/2 NPT adapters
- Money saving installation – it requires no venting!
- Durable copper immersion heating elements and brass top, threaded for easy replacement
- Self-modulating power control
- Energy Star certification – 99.8% energy efficiency.
- Warranty: 5-year limited warranty by Rheem
CON:
- This is a low-demand unit, not suitable for a whole-house application.
Tips:
- Temperature control: If you need to change the temperature control from Fahrenheit to Celsius, press the adjustment knob for 3 seconds.
- Quality of water: If your area that is known to have hard water which will cause scale build-up, you want to install a water treatment device to prevent damage to heat exchanger.
- Maintenance: Once a year, you want to check the connections on the inlet and outlet for cracks or leakage. Always fix minor damage before it becomes a bigger problem.
Summary
The Rheem RTEX-13 is an excellent low-demand electric tankless water heater for a small apartment or a bathroom application. It is compact at 12.63 inches tall, easy to install with included electric cable and adapters, and easy to operate via its digital temperature control. With its self-modulating power control, this Rheen RTEX-13 is 99.8% energy saving efficient. Rheem has been in business for almost 100 years, and they provide both excellent customer support and warranty. RTEX-13 comes with five-year heating chamber warranty and one-year parts limited warranty.
Heater Input table for Rheem RTEX-13 electric tankless water heater
Heater Input | Elements | Voltage | Max kW |
---|---|---|---|
13 kW | 2 | 240 V | kW/element = 6.5 kW; Max kW = 13 kW |
Best Seller: EcoSmart ECO 11 Electric Tankless Water Heater
Model: EcoSmart ECO 11 Electric Tankless Water Heater with patented Self Modulating Technology
Dimensions: 11.5″ H x 8″ W x 3.75″ D
Weight: 6.65 lbs
Voltage : 220 volts
Kilowatts: 11.8 kW
Flow rate: 2 GPM. Activation flow = 0.3 GPM. Inlet temperature 57°F = 1.9GPM; 62°F = 2.1 GPM.
Demand type: Low-demand, suitable for one-bathroom application.
Application: Point-of-use tankless water heater or multiple applications
We feature two EcoSmart ECO models, EcoSmart ECO 11 and EcoSmart ECO 27, in our top picks of electric tankless water heaters. Why? EcoSmart has demonstrated their reliability and quality products year after year with their limited lifetime warranty. We also like the patented Self Modulating Technology that minimizes energy consumption while producing endless hot water.
This EcoSmart ECO 11 is a best seller in low-demand and small capacity tankless water heater. It can produce enough hot water for one low-flow shower head and one sink at the same time. Or, consider installing this unit near your primary hot water source to as a “water heater booster”
PROs:
- Compact size saves valuable storage space
- Advanced self-modulating technology – will adjust how much energy needs based on how much hot water is needed
- Digital temperature control in 1-degree increments
- Temperature range from 80°F to 140°F
- Stainless steel heat exchange
- Thermal auto protection
- Heating elements are durable and are threaded for easy replacement
- Lifetime warranty for residential use.
CON:
- This model is a low-demand unit intended for small single use application.
Tips:
- You want to register your EcoSmart unit within 30 days of purchase and install it by a licensed professional.
Summary
The EcoSmart ECO 11 Electric Tankless Water Heater is a smaller capacity water heater that provides excellent performance at a low price-point. Its heating input of 11.8 kW is ideal for providing hot water for point-of-use or low-flow applications in a small home. It can also be installed as a booster to your primary hot water source. With its advanced self-modulating sensor technology, it can save up to 60% on the water heating cost. It is suitable for both warmer and colder climates: 1.9 GPM with inlet temperature 57°F.
Affordable, simple Installation, advance technology and limited lifetime warranty – that is why the EcoSmart ECO 11 is the Best Seller in the Low-demand tankless water heaters category.
Heater Input table for EcoSmart ECO 11 electric tankless water heater
Heater Input | Elements | Voltage | Max kW |
---|---|---|---|
11.8 kW | 2 | 220 V | kW/element = 5.5 kW; Max kW = 11.8 kW |
Key factors to consider:
To choose the best electric tankless water heater for your home, these are the key factors you must consider:
- Centralized vs. point-of-use tankless electric water heater
- A centralized tankless electric water heater is used when your best choice is to end up with a single water heater to meet all of the water heating needs of your house.
- A centralized system is often cheapest and easiest to install, especially if replacing a centralized storage water heater and utilities are already at the point of installation.
- However, electric tankless heaters, because of their simpler connection to utilities, especially favor point-of-use designs. It can be relatively simple to install a small tankless electric heater in an existing bathroom to provide hot water for your shower and sink.
- Read More about Centralized vs. point-of-use tankless water heater
- Flow rate – How to size your hot water needs?
- As with all tankless water heaters, the key to correctly sizing your purchase is to understand the flow-rate requirements of your situation.
- Flow rate is determined by the capacity of the tankless heater, the amount of hot water you use at any one time, and the temperature of the incoming water.
- Read More about how to size your hot water needs.
- Ambient temperature/temperature of incoming water
- It may surprise you to discover that the flow rate of you tankless water heater may be reduced by 1/3 if the incoming water temperature is reduced by 20°F.
- So don’t simply look at the flow rate specs of your tankless heater, check the flow rate at the lowest ambient temperatures you are likely to encounter in your installation.
- Many purchasers want a 50% cushion on rated flow rates vs calculated flow requirements to cover such needs.
- Electrical requirements of the water heater
- Voltage
- Amperage
- Circuit breaker requirements
- Benefits of electric Tankless water heaters.
- Tankless water heaters produce hot water on demand and instantly
- Endless hot water (no tank to empty)
- Electric tankless water heaters are more energy efficient than their storage tank equivalents
- Tankless water heaters are better for the environment than storage tank water heaters
- Tankless water heaters take much less space that their storage tank equivalents
- Lend themselves to point-of-use solutions
- Venting generally is not required
- Read More about benefits of electric tankless gas water heaters
- Buying guide of Electric Tankless water heaters.
- Do you need a high-demand, medium-demand or low-demand tankless?
- Demand driven by household size, appliances, life style
- Budget
- Factor in climate requirements—water inlet temperature
- Give yourself some upside cushion (perhaps 50%)
- Installation cost
- Centralized vs. point of service
- Operational cost
- Read More about Tankless water heater buying guide
Similar to a gas tankless water heater, you will have a decision to make as to whether you want to end up with a centralized (single) water heater or a point-of-use design that potentially utilizes several smaller water heaters to deliver instant hot water just where it’s needed.
Recap: top-rated on-demand electric water heaters
Preview | Product | Price | |
---|---|---|---|
Stiebel Eltron Tankless Heater – Tempra 36 Plus... | $849.00 $382.98 | View on Amazon | |
EcoSmart ECO 27 Tankless Water Heater, Electric,... | $599.00 $300.00 | View on Amazon | |
Rheem 240V Heating Chamber RTEX-13 Residential... | $279.99 | View on Amazon | |
EcoSmart ECO 11 Electric Tankless Water Heater,... | $299.00 $189.99 | View on Amazon |
Taking your family on a camping trip? Check out our portable on-demand water heaters.