Choosing the best under-sink tankless water heater for 120V power is key for applications like kitchen sinks, bathroom vanities, or small point-of-use installations where you need hot water instantly without waiting for it to travel from a distant central water heater. These compact units are energy-efficient, save space, and eliminate the need for large storage tanks.
Here are the top-rated 120V under-sink tankless water heaters for 2024:
1. EcoSmart POU 6 – Best for Overall Performance
The EcoSmart POU 6 is a highly efficient and compact point-of-use tankless water heater that runs on 120V power, making it perfect for under-sink applications in bathrooms and kitchens. It provides consistent hot water for sinks and is capable of handling light water demand with ease.
Key Features:
- Flow Rate: 1.0 to 1.5 GPM
- Power: 5.5 kW at 120V
- Best For: Bathroom and kitchen sinks, light-use applications
- Efficiency: 99.8%
- Temperature Control: Adjustable temperature settings
- Compact Size: Fits easily under sinks
Pros:
- High energy efficiency, no standby heat loss
- Compact and easy to install under sinks
- Heats water instantly for small fixtures
- Self-modulating technology saves energy by adjusting power based on flow rate
Cons:
- Only suitable for single fixture use (bathroom/kitchen sink)
- Not ideal for colder climates where inlet water temperature is very low
2. Bosch Tronic 3000 T 2.5 – Best for Easy Installation
While technically a small tank heater, the Bosch Tronic 3000 T 2.5 functions almost like a tankless water heater due to its 2.5-gallon capacity. It runs on 120V power and delivers hot water instantly to sinks. Its compact size makes it an excellent choice for tight under-sink installations, and it’s one of the easiest units to install.
Key Features:
- Capacity: 2.5 gallons (mini-tank)
- Power: 1.44 kW at 120V
- Best For: Bathroom/kitchen sinks, point-of-use applications
- Temperature Range: Adjustable up to 145°F
- Compact Design: Wall-mountable or floor installation
Pros:
- Simple plug-in installation, no special wiring needed
- Delivers hot water instantly due to small tank capacity
- Compact and fits under most sinks
- Can be connected to existing hot water lines for faster delivery
Cons:
- Not truly “tankless” but functions similarly for small-use applications
- Limited hot water supply; once the small tank is empty, you’ll need to wait for a quick reheat
3. Stiebel Eltron DHC-E 8 – Best for Advanced Features
The Stiebel Eltron DHC-E 8 is one of the more powerful under-sink tankless units that runs on 120V power. This German-engineered water heater comes with advanced flow control, ensuring a consistent water temperature even when water pressure varies. It’s perfect for high-demand point-of-use applications like multiple sinks or light commercial use.
Key Features:
- Flow Rate: 0.5 to 1.5 GPM
- Power: 7.2 kW at 120V
- Best For: High-demand sinks, multiple sinks in close proximity
- Temperature Control: Thermostatic temperature control for consistent heat
- Advanced Flow Control: Prevents temperature fluctuation with varying water flow
Pros:
- Advanced technology ensures steady water temperature
- More powerful than most 120V units, great for higher water demand
- Compact design fits neatly under sinks
- High-quality build, known for durability
Cons:
- More expensive than simpler models
- Requires slightly more installation effort compared to plug-in units
4. Rheem RTEX-11 120V – Best for Multiple Sink Use
The Rheem RTEX-11 is a compact and efficient tankless water heater designed to handle multiple point-of-use applications. With its digital thermostatic control, it provides precise temperature regulation, making it a versatile solution for small bathrooms, kitchen sinks, and even laundry rooms.
Key Features:
- Flow Rate: 1.5 to 2.0 GPM
- Power: 11 kW at 120V
- Best For: Small homes, multiple sinks, light showers
- Temperature Range: 80°F to 140°F with digital control
- Compact Design: Ideal for under-sink installation
Pros:
- Handles more than one sink, depending on usage
- Digital temperature control for precise adjustments
- Energy efficient and space-saving design
- Easy to install and maintain
Cons:
- Overkill for very light-use installations (single sink)
- Requires electrical work, including dedicated circuit breaker
5. Camplux TE11 Electric Tankless Water Heater – Best Budget Option
If you’re looking for an affordable under-sink tankless water heater that operates on 120V power, the Camplux TE11 is a solid choice. It’s designed for point-of-use applications and is perfect for bathroom or kitchen sinks, offering instant hot water at a fraction of the cost of higher-end models.
Key Features:
- Flow Rate: 1.2 to 1.5 GPM
- Power: 11 kW at 120V
- Best For: Low-demand point-of-use applications (sinks)
- Compact Design: Easy to fit in tight spaces under sinks
- Temperature Range: Adjustable settings for temperature control
Pros:
- Affordable and easy to install
- Delivers instant hot water for small fixtures
- Compact and space-saving design
- Simple installation with 120V power
Cons:
- Not as powerful as higher-end models
- Limited to single-point applications (one sink at a time)
Comparison Table: Best 120V Under-Sink Tankless Water Heaters
| Model | Best For | Flow Rate (GPM) | Power (kW) | Key Features | Price Range |
|---|---|---|---|---|---|
| EcoSmart POU 6 | Single sinks, small applications | 1.0-1.5 GPM | 5.5 kW | Compact, self-modulating, high efficiency | $$ |
| Bosch Tronic 3000 T 2.5 | Easy installation, low demand | 2.5-gallon capacity | 1.44 kW | Mini-tank, plug-in installation | $ |
| Stiebel Eltron DHC-E 8 | High-demand point-of-use | 0.5-1.5 GPM | 7.2 kW | Advanced flow control, thermostatic temperature | $$$ |
| Rheem RTEX-11 120V | Multiple sinks, small households | 1.5-2.0 GPM | 11 kW | Digital thermostatic control, handles multiple fixtures | $$$ |
| Camplux TE11 | Budget-friendly single sinks | 1.2-1.5 GPM | 11 kW | Affordable, easy to install | $ |
Key Considerations for Choosing a 120V Under-Sink Tankless Water Heater
- Flow Rate (GPM):
- The flow rate measures how many gallons of water per minute the heater can handle. If you need the heater for a single fixture, 1.0-1.5 GPM is sufficient. For multiple sinks or higher demand, look for units with 2.0 GPM or more.
- Power (kW):
- The more power the unit has, the faster it can heat water. A 5.5 kW unit is good for single-sink use, but if you’re looking to power multiple fixtures, consider a more powerful unit like the Rheem RTEX-11 or Stiebel Eltron DHC-E 8.
- Installation:
- Some units, like the Bosch Tronic 3000, are incredibly easy to install and simply plug into an outlet. Others, like the Rheem RTEX-11, may require some minor electrical work or the addition of a dedicated breaker.
- Temperature Control:
- Digital or manual temperature controls are useful for setting and maintaining consistent water temperatures. Models like the Rheem RTEX-11 and Stiebel Eltron offer digital thermostatic control for precise adjustments.
- Energy Efficiency:
- Most 120V under-sink water heaters are highly efficient, often 99% or more. Look for models with self-modulating technology, like the EcoSmart POU 6, which adjust energy usage based on water flow.
Final Recommendation
- For single-sink use in small bathrooms or kitchens, the EcoSmart POU 6 offers the best balance of performance and efficiency.
- If you prefer a plug-and-play installation, the Bosch Tronic 3000 T 2.5 is an easy-to-install option with quick hot water access.