The single biggest frustration for homeowners making the switch to a tankless water heater is not the upfront cost—it’s the cold shock of a shower that suddenly turns lukewarm because the unit can’t keep up. That’s the moment you realize a poorly chosen electric tankless unit is worse than the gas tank you were trying to replace. The good news is that modern 36kW electric tankless heaters, when matched to your home’s electrical capacity, deliver nearly 100% efficiency and endless hot water for multiple simultaneous fixtures.
I’m Min — the co-founder and writer behind Gadgets Feed. I’ve spent hundreds of hours analyzing specifications, cross-referencing real customer experiences, and breaking down the electrical and flow requirements across the most popular electric tankless water heater models on the market.
After combing through dozens of units and thousands of verified reviews, I’ve identified the models that consistently deliver reliable, steaming-hot water without performance dips. This guide covers everything you need to confidently choose the best 60 gallon electric water heater for your home’s specific demands.
How To Choose The Best Electric Tankless Water Heater
Jumping from a traditional tank to an electric tankless system is one of the most satisfying upgrades you can make for your home’s energy efficiency and space utilization. However, the purchase decision hinges on three interconnected factors: your home’s electrical panel capacity, your region’s incoming groundwater temperature, and your household’s peak simultaneous hot water demand. Get these right, and you’ll enjoy endless hot water with zero standby energy loss.
Kilowatt Rating vs. Flow Rate
The kW rating is the single most important spec because it dictates how much heat the unit can generate to raise the water temperature. A 36kW unit provides significantly more heating capacity than a 27kW model. In practical terms, this means a 36kW heater can supply up to ~7 GPM at a 35°F temperature rise, enough for 3 to 4 showers running concurrently. If you live in the northern US where incoming water can drop to 40°F in the winter, you need a higher kW unit to achieve a comfortable 110°F shower at a usable flow rate.
Electrical Infrastructure Requirements
Every high-power electric tankless heater demands serious amperage from your breaker panel. A 36kW unit drawing 150 amps requires four dedicated double-pole 40A breakers and 8 AWG copper wiring. Your home must have at least a 200-amp main service to handle this load. Before falling in love with a specific model, have a qualified electrician assess your panel’s available space and capacity. This is not a DIY electrical job, and skipping this step is the most common reason for returns and frustration.
Self-Modulating Technology and Build Quality
Look for units with self-modulating flow control. This feature allows the heater to intelligently dial its power consumption up or down based on real-time water flow, preventing temperature fluctuations when someone turns on a sink while the shower is running. Advanced units also include copper or brass heating elements for better thermal conductivity and corrosion resistance compared to basic steel elements. A digital display and temperature control (typically adjustable from 86°F to 140°F) are standard on reliable models.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Rheem RTEX-36 | Tankless | Overall Reliability | 36kW / 99.8% Efficiency / 6 GPM | Amazon |
| Ecosmart ECO 36 | Tankless | Value & Performance | 36kW / 99.8% Efficiency / 6 GPM | Amazon |
| ThermoMate 36kW | Tankless | Precise Temperature Control | 36kW / 99.8% Efficiency / 8.8 GPM | Amazon |
| Mizudo 36kW | Tankless | High Flow Capacity | 36kW / 98% Efficiency / 8.7 GPM | Amazon |
| Stiebel Eltron Tempra 36 | Tankless | German Engineering | 36kW / High Efficiency / 1.5 GPM (per unit) | Amazon |
| WINTEMP WM27V Plus | Tankless | Smart WiFi Control | 27kW / Up to 6.5 GPM / WiFi | Amazon |
| Rinnai RX199iN | Gas Tankless | Highest GPM Capacity | 199,000 BTU / 11.1 GPM / UEF .98 | Amazon |
| Suburban Advantage SAW6DE | RV Gas/Electric | RV Direct Fit Upgrade | 6 Gal / 10,000 BTU / Porcelain Lined | Amazon |
| CAMPLUX 6 Gallon | RV Hybrid | RV Gas/Electric Hybrid | 6 Gal / 12,000 BTU / 1440W | Amazon |
| Suburban ST-60 | RV Tankless | Endless RV Hot Water | 60,000 BTU / Tankless / 6 Gal equiv. | Amazon |
| Camco Kuuma 6 Gal | RV Electric | Marine/RV Direct Swap | 6 Gal / 1500W / 120V | Amazon |
In‑Depth Reviews
1. Rheem RTEX-36 36kW Electric Tankless Water Heater
The Rheem RTEX-36 is a 36kW, 99.8% efficient electric tankless water heater that consistently delivers enough hot water for a 2,500-square-foot house with multiple showers running simultaneously. It uses an external adjustable thermostatic control and 3/4-inch NPT connections at the bottom. This model draws 150 amps and requires four dedicated double-pole 40A breakers with 8 AWG copper wire, so a 200-amp main service panel is highly recommended.
Real customers report that the Rheem RTEX-36 heats water to 140°F instantly, with a noticeably higher flow rate than competing 36kW units from Ecosmart. One reviewer upgraded from an Ecosmart that failed yearly and noted the Rheem has been perfectly reliable. Another user with a cold-climate home found the heat-up time slightly longer than a tank heater but praised the space savings and elimination of leak risk associated with traditional tanks.
The unit uses brass and copper heating elements for efficient heat transfer and corrosion resistance. Its silver and metallic housing has a compact wall-mount design, measuring just 17 inches wide by 17 inches high. The external temperature control knob is easy to read and adjust without removing the front cover.
Why it’s great
- 99.8% energy efficiency eliminates standby heat loss
- Brass and copper construction provides excellent thermal transfer
- Proven reliability compared to other 36kW options in its price tier
- Compact wall-mount design saves significant floor space
Good to know
- Requires 4x double-pole 40A breakers and 200-amp service minimum
- Professional electrician installation is mandatory
- Hot water delivery at distant faucets takes slightly longer than a tank heater
2. Ecosmart ECO 36 36kW Electric Tankless Water Heater
The Ecosmart ECO 36 is one of the most well-known electric tankless water heaters on the market, a 36kW unit that claims 99.8% energy efficiency. It features a digital output temperature display and self-modulating technology which adjusts power consumption based on the incoming water temperature and flow rate. The unit requires the same heavy electrical infrastructure as the Rheem: four 40-amp double-pole breakers and 8 AWG wiring.
Customer experiences over four to five years of use are overwhelmingly positive. One reviewer reported this unit has been running strong for four years, replacing an 80-gallon tank and providing endless hot water for a family of five. Another user noted the unit can handle one shower during Ohio winters and two simultaneously in summer, confirming that actual GPM depends heavily on ground water temperature. Several users highlight the importance of registering the product within 30 days for warranty coverage.
The unit’s white housing and compact 21-inch by 17-inch form factor makes it relatively easy to mount on a wall in a utility room or garage. The digital display shows the outgoing water temperature, which is adjustable via simple button controls. The unit ships with a 3/4-inch NPT water connection and includes rough-in plumbing brackets.
Why it’s great
- 99.8% efficiency with self-modulating power usage
- Long-term reliability reported by customers with 4+ years of use
- Sleek white design with digital temperature display
- Manufactured in the United States
Good to know
- Requires 4x40A breakers and 200-amp service minimum
- Warranty must be registered within 30 days of purchase
- One customer reported motherboard failure; customer service performance was inconsistent
3. ThermoMate 36kW Electric Tankless Water Heater
The ThermoMate 36kW is a self-modulating electric tankless water heater with a rated flow of 8.8 GPM and 99.8% efficiency. It uses advanced self-modulating technology that adjusts energy use in real-time, which the manufacturer claims can save up to 60% on water heating costs vs. a traditional tank. The unit’s digital display and intuitive control knob allow 1-degree temperature adjustments between 80°F and 140°F.
Real customers with the 18kW variant of this unit reported a staggering reduction in their electric bill—from to per month—in Central Florida, while handling two concurrent showers and laundry. A home with hard water found the unit performed well with slightly slower warm-up but got very hot. The design separates the heating element from the water flow, making maintenance significantly easier than integrated-element designs.
This unit requires four dedicated double-pole 40A breakers with 4 x 8 AWG copper wire and a minimum 200-amp main service. The robust metal housing measures just 12.99 inches wide by 18.31 inches high by 4.41 inches deep. The anti-freeze protection and automatic dry-fire shutdown add an extra layer of safety for homeowners in colder climates.
Why it’s great
- Separated heating element design simplifies maintenance
- Up to 8.8 GPM flow rate accommodates large households
- 1-degree temperature increments for precise control
- ETL certified with dry-fire and overheat protection
Good to know
- Requires 4x40A breakers and 200-amp main service
- One customer reported no hot water at normal flow rate on a lower kW variant
- Long-term durability with hard water is still being established
4. Mizudo 36kW Tankless Water Heater Electric
The Mizudo 36kW (model EQUIK 36) is an electric tankless water heater with a standout flow rate of up to 8.7 GPM, enough to simultaneously supply 5-6 points of use. It claims 98% high thermal efficiency and uses a copper cup heating element for efficient thermal transfer. The unit’s smart system fine-tunes power 20,000 times per second to maintain temperature stability within ±1°F, adjustable via LED touch display between 86°F and 140°F.
Customer feedback is mixed but informative. One user praised the compact design and instant hot water for a single sink or light use, noting the 2.6 GPM performance was consistent. Another buyer warned that the unit failed in an unheated crawlspace in the Pacific Northwest due to freezing, a critical installation limitation for electric tankless heaters. A third customer purchased the unit in June, installed it in September, and reported a burst fitting in December that flooded a shop, causing in damage.
This unit requires four 40-amp double-pole breakers and 4 sets of 8 AWG wiring, plus a 3/4-inch NPT water connection. Its white and compact dimensions of 17.1 inches high by 18.5 inches wide by 3.7 inches deep make it one of the slimmest high-power models available. The LED display with error codes is helpful for troubleshooting.
Why it’s great
- 8.7 GPM max flow rate suitable for 5-6 simultaneous fixtures
- Copper cup heating element provides efficient heat transfer
- ±1°F temperature stability with 20,000 adjustments per second
- Ultra-compact 3.7-inch depth for tight installation spaces
Good to know
- Not freeze-resistant; must be installed in a conditioned, interior space
- Requires 4x40A breakers and 200-amp service
- Several reports of catastrophic water damage due to burst fittings
- Customer service responsiveness is inconsistent
5. Stiebel Eltron Tempra 36 Plus 36kW Tankless Water Heater
The Stiebel Eltron Tempra 36 Plus is a 36kW electric tankless water heater built in Germany, known for its solid construction and exclusive Advanced Flow Control system that automatically adjusts flow to maintain the set temperature. The unit uses self-modulation energy technology and features a digital display for precise temperature setting. It requires three 50-amp double-pole breakers instead of four 40-amp ones, a slightly different electrical configuration than the Rheem and Ecosmart options.
Owner experiences highlight the quality and longevity of this unit. One customer replaced the same Stiebel Eltron model after 14 years of service, with the new unit performing excellently for four bathrooms. Another user reported that the unit produces 100°F+ hot water in 1-2 minutes compared to 5-7 minutes for a 75-gallon tank heater. However, one buyer noted a significantly high electric bill (over ) and inconsistent temperature, eventually returning to a tank heater.
The Tempra 36 Plus measures 16.63 inches wide by 14.5 inches high. It uses a copper heating system encased in a white metal housing. The unit’s compact size and German engineering are often cited as its main selling points, but potential buyers should be aware that the unit may not be compatible with solar+battery setups due to its high instantaneous power draw of 10-15 kW.
Why it’s great
- Made in Germany with high build quality and longevity (14+ year lifespan reported)
- Advanced Flow Control maintains consistent outlet temperature
- Compact design with intuitive digital controls
- Excellent manufacturer technical support
Good to know
- Requires 3x50A breakers, which may need different panel space
- High instantaneous power draw makes solar/battery backup difficult
- Some customers report inconsistent temperature and high operating costs
- Hot water delivery to distant faucets can take 7-10 minutes
6. WINTEMP WM27V Plus 27kW Tankless Water Heater
The WINTEMP WM27V Plus is a 27kW tankless electric water heater that offers a unique value proposition: built-in WiFi control via the Smart Home and Tuya Smart apps. Rated at up to 6.5 GPM, this unit is designed for 2-4 points of use in a mid-sized home. It uses self-modulating technology and a digital temperature display, and is ETL certified. The electrical requirement is three 40-amp double-pole breakers with 3 sets of 8 AWG wiring.
Customer feedback is very positive for this entry-level high-power model. A review of the 27kW version noted it handled a washer, dishwasher, and shower simultaneously with no temperature fluctuation in 50-60°F incoming water. Another user praised the all-metal steel build, which feels more durable than cheaper plastic alternatives. The WiFi functionality allows remote temperature monitoring and control, as well as real-time water and electricity usage tracking.
The unit measures 15.9 inches high by 13 inches wide by 4.2 inches deep, offering a space-saving footprint. The internal cast-aluminum heating system is designed for efficient heat transfer. A minor complaint from one user was the lack of a certification logo on the product itself, though the unit ships with ETL standards listed.
Why it’s great
- WiFi control for remote temperature adjustment and usage monitoring
- Compact 4.2-inch depth saves significant wall space
- Self-modulating technology prevents temperature fluctuations
- Stable performance with multiple simultaneous appliances
Good to know
- Requires 3x40A breakers and 200-amp service recommended
- Limited to 6.5 GPM, sufficient for 2-4 points of use but not whole-house 5-6 fixtures
- Some users questioned the physical ETL certification marking
7. Rinnai RX199iN Condensing Smart Sense Tankless Water Heater
The Rinnai RX199iN is a condensing tankless water heater that runs on either natural gas or propane, delivering a massive 11.1 GPM flow rate with a UEF efficiency rating of 0.98. It is not an electric unit, but it earns a place on this list for homeowners with gas hookups who want the highest possible flow rate without the massive electrical infrastructure demands of a 36kW electric unit. The Versa Vent system allows indoor or outdoor installation.
Real-world owner experiences are excellent. One customer reported the unit has been running for 6 months in a 3-bedroom home with a family of 5, handling multiple showers with no pressure or temperature drop. Another reviewer noted it replaced their 11-year-old Rinnai, and the plumber installed it in just hours. The quiet operation is frequently praised, and the unit’s compact suitcase-like size (18.5 inches wide by 30.11 inches high) saves significant floor space.
The RX199iN includes a Smart Sense gas control system that automatically detects the fuel type (propane vs. natural gas). It also includes a Quick Flush feature for simplified maintenance and the ability to connect to the Rinnai Central App for WiFi control and troubleshooting. Professional installation is highly recommended, and Rinnai provides a dedicated installer locator on their website.
Why it’s great
- 11.1 GPM flow rate supports up to 7 fixtures simultaneously
- UEF 0.98 efficiency for low operating costs
- Indoor or outdoor installation flexibility
- Smart Sense fuel detection works with natural gas or propane
Good to know
- Requires professional installation by a qualified technician
- Hot water delivery to distant faucets may take 20-30 seconds longer than a tank
- Higher upfront cost than most electric tankless units
- Requires gas line and proper venting, not suitable for all homes
8. Suburban Advantage Direct Fit SAW6DE 6 Gallon RV Water Heater
The Suburban Advantage SAW6DE is a 6-gallon direct-fit RV water heater designed to replace older Atwood and Dometic units without sidewall modifications. It uses a 10,000 BTU LP gas burner with a direct spark ignition (DSI) system and includes an Incoloy electric element for 120V operation. The recovery rate is 14.14 gallons per hour on gas, 6.10 on electric, and 20.24 using both simultaneously.
Customer experiences highlight the true “direct fit” nature of this unit. One reviewer successfully replaced a leaking Atwood unit in a 2016 Chaparral 5th wheel with no cut-out modifications. Another user noted the mounting bracket folds out via perforations but the instructions were lacking. One unit arrived with a bent front shroud that required manual correction, though the fit and function were otherwise perfect.
The tank is porcelain-lined steel with a replaceable anode rod that doubles as a drain, simplifying maintenance. The unit weighs 41 pounds and measures 17.5 inches wide by 14.25 inches high. It is an ideal upgrade for RV owners looking for a durable residential-style tank that fits perfectly into existing 6-gallon cutouts.
Why it’s great
- Direct fit replacement for most 6-gallon RV cutouts with no modifications
- Porcelain-lined steel tank is more durable than standard aluminum tanks
- Dual power (gas + electric) provides recovery flexibility at campsites
- Replaceable anode rod protects against corrosion and simplifies draining
Good to know
- Some units may arrive with minor cosmetic damage to the front shroud
- Installation instructions could be clearer for first-time DIYers
- Requires 2.5-inch riser for water line clearance in some RV configurations
9. CAMPLUX 6 Gallon RV Water Heater (Gas/Electric/Hybrid)
The CAMPLUX 6-gallon RV water heater offers true heating flexibility with propane (12,000 BTU), electric (1440W), or hybrid modes. This allows RVers to run propane when boondocking, switch to electric at RV parks to save fuel, or combine both for fast recovery when multiple people need hot showers. The unit is designed as a direct fit for standard 13 x 13-inch cutouts with a 15 x 15-inch exterior door.
Customer feedback is generally positive but highlights installation hurdles. One user noted the unit works wonderfully but was a lot of work converting from a gas-only system to gas/electric/both. Another user emphasized that you should absolutely check the physical dimensions because the unit was hard to install when the cutout was slightly off. The interior-mounted control panel allows mode and temperature adjustments without stepping outside the RV.
The tank is porcelain-lined steel with an integrated anode rod for long-term corrosion protection, essential for full-time RVers. The unit is CSA certified with safety features including dry-boil protection and over-temperature protection. It measures 15.2 inches wide by 15.2 inches high and weighs 35 pounds.
Why it’s great
- Three heating modes (propane, electric, hybrid) for maximum flexibility
- Porcelain-lined steel tank with anode rod resists corrosion
- Interior control panel for easy mode and temperature adjustment
- CSA certified with multiple built-in safety protections
Good to know
- Installation can be challenging if existing cutout is not exactly 13 x 13 inches
- Some customers reported poor technical support from the manufacturer
- Requires careful conversion from gas-only to gas/electric plumbing
10. Suburban Tankless 60,000 BTU RV Water Heater (ST-60)
The Suburban ST-60 is a tankless RV water heater rated at 60,000 BTU, offering endless hot water without the weight or bulk of a storage tank. It features enhanced flame-out protection that instantly cuts the gas supply in response to low propane pressure, a scald protection kill switch that maintains a maximum water temperature of 131°F, and a child lock that prevents outlet temperatures from exceeding 113°F. Freeze protection activates in low temperatures when power and propane are available.
Real customer experiences are very positive. One reviewer replaced a leaking Atwood tank heater and reported endless hot water reaching both the bathroom and kitchen quickly. Another user installed the unit in about an hour and confirmed it heats water in 5-9 seconds. The unit’s digital control center must be hardwired into the RV’s 12V system, requiring some additional wiring. The tankless design saves significant weight compared to a traditional tank, weighing just 21 pounds.
A notable caution from a buyer is that not all ST-60 units are identical—one customer received a variant (5482A) that was incompatible with their OEM 5382 wiring, causing an EC error. The exterior door (model 6285APW or 6285AEB) is sold separately, which may catch some buyers off guard.
Why it’s great
- Endless hot water with no recovery wait time
- Weighs only 21 pounds, much lighter than tank-based alternatives
- Integrated child lock and scald protection enhance family safety
- Active freeze protection prevents winter damage
Good to know
- Exterior door is sold separately
- Unit variants may have different wiring configurations (check OEM compatibility)
- Requires 12V DC wiring for the digital control center
- Low flow (mixing cold water) can cause the flame to shut off
11. Camco Kuuma Marine 6 Gallon Electric Water Heater
The Camco Kuuma Marine 6-gallon electric water heater is a simple, reliable entry-level RV and marine replacement heater. It runs on standard 120V AC or 12V DC power with a 1500W heating element. The unit is designed as a direct swap for older 6-gallon units, with the same 16-inch by 13.6-inch dimensions to fit into existing cutouts without modification. It features a pilot light window and the maximum temperature reaches 210°F.
Customer feedback is very specific to RV and boat owners. One reviewer used it to replace an old rusted unit in a 1995 RV and confirmed the dimensions were identical, with the plumbing fittings lining up perfectly. Another user installed it in a 1978 GMC Kingsley 26-foot motorhome and reported outstanding fit and function. A boat owner found it was a “perfect fit” for a 350 Rinker. One buyer did note that the construction felt like “China junk” and communication was slow, but the unit functioned.
The unit’s simplicity is its main advantage—no complex electronics, no gas lines, just a standard 120V plug-in or 12V DC connection. The wall-mount design includes a pilot light window for visual status indication. Buyers should be aware that the 1500W element means a slower recovery time compared to gas or hybrid options, but it’s perfectly adequate for small RVs and boats.
Why it’s great
- Direct swap replacement for 6-gallon units in most RVs and boats
- Simple 120V AC or 12V DC operation with no gas lines required
- Standard 16-inch by 13.6-inch dimensions fit existing cutouts
- Affordable entry price for RV water heating
Good to know
- 1500W electric-only heating means slow recovery between showers
- Limited to 6 gallons of stored hot water at a time
- Some units may have perceived lower build quality
FAQ
Can a 36kW electric tankless water heater supply two showers simultaneously?
Do I need a 200-amp service panel for a 36kW electric tankless water heater?
How much does it cost to operate a 36kW electric tankless water heater per month?
Can I install an electric tankless water heater in an unheated garage or crawlspace?
What is the difference between a condensing and non-condensing tankless water heater?
Final Thoughts: The Verdict
For most homeowners making the switch from a traditional tank, the best 60 gallon electric water heater equivalent in tankless form is the Rheem RTEX-36 36kW because it combines proven reliability, 99.8% efficiency, and a strong brand reputation with brass and copper construction. If you want smart remote control and monitoring, grab the WINTEMP WM27V Plus. For RV owners who need endless hot water without the weight of a tank, nothing beats the Suburban ST-60 tankless unit.











