Here’s an overview of the Best Tankless Water that we’ll explore today:
Tankless water heaters deliver hot water on demand, offering space savings, reduced standby energy, and the ability to scale hot water for point-of-use or whole-home needs. This review analyzes five widely available models across a price spectrum from budget to premium, representing both point-of-use electric units and higher-capacity whole-home solutions. Our methodology combines manufacturer specifications, sizing guidance, and real-world expectations: we examine electrical requirements, maximum flow rates (GPM), temperature rise capabilities, installation considerations, and warranty coverage. By contrasting 13 kW, 18 kW, 24 kW, and 3 kW options, we illustrate how small differences in wattage, modulation, and controls translate into real-world performance in typical home scenarios. The products covered are EcoSmart ECO 11 (Product 0), Rheem RTEX-18 (Product 1), LECLOC 3kW 120V (Product 2), xwdzswgs 3,000W 110V (Product 3), and Rheem RTEX-24 (Product 4).
1. EcoSmart ECO 11 Electric Tankless Water Heater
- Brand: EcoSmart
- Manufacturer: EcoSmart
The EcoSmart ECO 11 is EcoSmart’s small-form, high-efficiency 13 kW electric tankless model designed for point-of-use or compact installations. It advertises endless on-demand hot water with self-modulating technology that adjusts output to meet demand, maintaining water temperature within about 1 degree of the setpoint. At a listed 13 kW and 240 V, its maximum flow is roughly 3.1 GPM, making it well-suited for a bathroom sink, a small basin, or a single low-flow application. The unit is exceptionally compact (11.5 x 8 x 3.75 inches) and claims 99% thermal efficiency, which translates to lower standby losses compared with traditional storage heaters. It employs an LED display and comes with a lifetime warranty on electronics, exchanger, and element, though labor and incidental damages aren’t covered.
In practice, the ECO 11 shines when used for low-flow, point-of-use needs where inlet water temperatures aren’t extremely cold. The self-modulating feature helps maintain a stable outlet temperature as flow varies, but in areas with very cold inlet water, achieving higher flow around 2–3 GPM may require a larger model or multiple units. Installation requires 220 V wiring and careful sizing to ensure the downstream point-of-use device does not exceed the unit’s thermal capacity. Noise is typically minimal, and the low profile facilitates under-sink mounting or wall installation in tighter spaces.
Pros
- Self-modulating technology maintains stable temperature while saving energy
- Compact footprint; easy wall or under-sink mounting
- Very high energy efficiency (99.8%)
- Good for low-flow point-of-use applications
- Lifetime warranty on electronics and heat exchanger
Cons
- Limited to about 3.1 GPM at typical inlet temps
- Not ideal for showers or multi-point hot water needs
- Requires 240 V circuit and proper electrical wiring
2. Rheem 18kW 240V Tankless Electric Water Heater
- Brand: Rheem
- Manufacturer: Rheem
Rheem’s RTEX-18 presents a higher-capacity 18 kW electric tankless option with a robust copper immersion heating element and self-modulation. It delivers up to 4.4 GPM and features an external digital thermostat with LED display for precise temperature control within 1 degree. The unit is designed for straightforward installation with bottom 3/4 inch NPT water connections and a wall-mount form factor, while the copper elements aim to provide durability and rapid heat transfer. It’s marketed for whole-home or larger-point-of-use configurations, with a 140°F maximum temperature and 99.8% efficiency.
In terms of performance, the RTEX-18 excels in households requiring more than a single small-tap hot water supply. The self-modulation helps track demand while avoiding overshoot; however, the actual GPM achievable depends on incoming water temperature. In cold climates, 4+ GPM may be challenging without compromising outlet temperature, so pairing with a tempering valve or planning for staged usage can optimize results. The unit’s dimensions (roughly 14.5 x 18.25 inches) imply a deeper footprint and a need for adequate space in the mechanical room or closet.
Pros
- Higher output for multiple taps or small homes
- Digital temperature control with 1-degree precision
- Copper immersion elements offer durability and fast heating
- Relatively easy installation with standard water connections
- High efficiency (99.8%)
Cons
- Requires a substantial electrical service (3 x 40 A breakers; often 200 A service)
- Larger footprint than many point-of-use units
- Performance highly dependent on inlet water temperature
3. Mini Tankless Under Sink Instant Hot Water Heater Electric 3kW 120V Plug-in
- Brand: LECLOC
- Manufacturer: LECLOC
LECLOC’s 3kW 120V mini tankless unit is a point-of-use solution designed for under-sink installation with a plug-in configuration. It supports temperature adjustment from 30°C to 55°C via a knob or digital display, with integrated protections like leakage, overheat, and dry-fire protection plus IPX4 waterproofing. The product description emphasizes suitability for 1-point-of-use scenarios and warns that the 3 kW output is insufficient for showers or multi-tap use, pushing users toward higher wattage models for broader needs. A 120V supply means it can be plugged into standard outlets, which makes it widely accessible but limits power delivery.
Real-world performance with 3 kW and 120 V typically yields limited GPM and modest temperature rise, making it suitable for a sink or small basin with low hot-water demand. The enlarged LED display and intelligent self-modulating behavior help maintain consistent temperature under modest flow. For better performance, consider the higher wattage 6 kW 240 V model if you have 240 V wiring and a larger hot water demand. Installation requires attention to circuit protection and vertical mounting to prevent element issues.
Pros
- Plug-in 120V operation enables easy, flexible installation
- Integrated protections and IPX4 waterproofing
- Self-modulating for stable temperature at low flow
- Affordable entry point for point-of-use hot water
- Under-sink footprint suitable for tight spaces
Cons
- 3 kW output limits flow and temperature rise
- Not suitable for showers or multi-tap use
- Requires vertical installation and careful electrical considerations
4. Tankless Water Heater Electric 110V
- Brand: xwdzswgs
- Manufacturer: xwdzswgs
This 110V, 3000W under-sink tankless heater from xwdzswgs targets budget-conscious users seeking instant hot water at the point of use. It claims rapid temperature rise (82°F at 0.3 GPM and 131°F at 0.5 GPM) with a compact, IP-rated design and an LED display. The unit emphasizes safety features like water-electric isolation and dry-boil protection, along with a durable build and a 2.42 lb weight. It’s positioned as an affordable, space-saving option for kitchens or baths where low-flow, point-of-use hot water suffices.
In practice, this model is best for tasks such as washing hands or quick small-volume uses rather than showering. Its 110V plug and compact dimensions simplify installation, but the 0.3–0.5 GPM performance means water temperature can drop quickly if flows increase even slightly. Users in colder climates may notice reduced performance due to lower inlet water temperatures, and the vertical installation requirement must be followed to avoid element faults.
Pros
- Very affordable upfront price
- Compact and easy to install with standard 110V outlet
- LED display and straightforward control
- IPX4 protection and safety features
- Minimal space requirement for under-sink use
Cons
- Limited to low-flow applications (no showers)
- Performance highly sensitive to inlet water temperature
- Lower GPM limits than higher-wattage or 240V units
5. Rheem RTEX-24 24kW 240V Electric Tankless Water Heater
- Brand: Rheem
- Manufacturer: Rheem
Rheem’s RTEX-24 is a premium, high-capacity 24 kW tankless electric unit designed for whole-home use or larger hot-water demands. It uses self-modulating technology and a 240 V supply with three 40 A double-pole breakers, targeting households with higher flow requirements up to 5.9 GPM and a maximum temperature of 140°F. The unit features an LED display, copper immersion elements, and a durable stainless-steel finish. It’s explicitly pitched for homes capable of supporting a substantial electrical service (recommended 200 A service) and emphasizes steady performance across varying inlet temperatures.
In real-world operation, the RTEX-24 delivers robust, continuous hot water for multiple simultaneous taps, provided the electrical system and plumbing can accommodate the load. The larger physical footprint and heavier weight (approx. 17.8 lb) require sturdier mounting and space planning. Given the high electrical demands, coordination with a licensed electrician is essential to ensure panel capacity, wiring, and breaker placement meet code requirements. Expect excellent performance in typical home environments with adequate power supply.
Pros
- High maximum flow (up to 5.9 GPM)
- Precise 1-degree temperature control increments
- Three copper heating elements and durable construction
- Suitable for whole-home use with multiple simultaneous demands
- LED display and easy digital adjustments
Cons
- Requires substantial electrical service (3 x 40 A breakers, 200 A service recommended)
- More complex installation and space requirements
- Higher upfront cost and wiring considerations
Frequently Asked Questions
We’ve compiled answers to the most common questions about tankless waters to help you make an informed decision.
Conclusion
The 5-model lineup demonstrates how capacity, electrical service, and installation constraints shape real-world outcomes.
For minimal space and lower demand, EcoSmart ECO 11 and Rheem RTEX-18 provide strong, reliable performance with straightforward installations.
High-demand households requiring simultaneous hot water should favor RTEX-24, provided electrical infrastructure is adequate. Budget-minded users can consider xwdzswgs or LECLOC 3kW 120V, tailoring expectations to flow and climate conditions..