Upgrading to a 120 volt tankless water heater is a smart move for instant hot water in kitchens, bathrooms, or RVs. These compact, on-demand units save space and energy by heating water only when you need it. Our expert-tested roundup cuts through the noise to help you find the perfect model for your home.
In This Article
- 1 Quick Product Comparison
- 2 Our Top 10 Best 120 Volt Tankless Water Heater Reviews – Expert Tested & Recommended
- 2.1 1. Hydro Master Brass Tankless Water Heater Service Valve Kit with Pressure Relief Valve
- 2.2 2. Under Sink Tankless Water Heater Electric 120V for Instant Hot Water in Kitchen or Bathroom
- 2.3 3. Ranein 4-Gallon 120V Electric Mini-Tank Water Heater for Instant Point-of-Use Hot Water
- 2.4 4. SIVUATEK 240V 14kW Electric Tankless Water Heater for On-Demand Hot Water in Your Home
- 2.5 5. Rheem 3.5kW 120V Point of Use Thermostatic Tankless Electric Water Heater
- 2.6 6. 3kW 120V Under Sink Tankless Water Heater with Digital Display and Thermostatic Control
- 2.7 7. Bosch ES4 4-Gallon 120V Electric Mini-Tank Water Heater for Wall or Floor Mounting
- 2.8 8. 8-Gallon 120V Electric Under Sink Water Heater for Instant Hot Water in RVs or Kitchens
- 2.9 9. 3000W 110V Electric Tankless Water Heater with Digital Display for On-Demand Hot Water
- 2.10 10. Under Sink Tankless Water Heater Electric 120V for Instant Hot Water in Kitchen or Bathroom
- 3 Complete Buying Guide for Best 120 Volt Tankless Water Heater
- 4 Frequently Asked Questions
Quick Product Comparison
Our Top 10 Best 120 Volt Tankless Water Heater Reviews – Expert Tested & Recommended
1. Hydro Master Brass Tankless Water Heater Service Valve Kit with Pressure Relief Valve
This all-in-one valve kit makes installing a tankless water heater a breeze. It’s built with heavy-duty brass for a leak-free, reliable connection right out of the box.
Key Features That Stand Out
- ✓ Forged lead-free brass construction for maximum durability
- ✓ Complete kit with isolation valves and a 150 PSI pressure relief valve
- ✓ Full port ball valves ensure minimal flow restriction
- ✓ Compatible with major brands like Rheem and Rinnai
Why We Recommend It
We recommend it because it takes the guesswork out of installation. The factory-tested valves provide peace of mind, and the robust build means it will last for years.
Best For
Best for homeowners or installers who want a professional-grade, complete valve set for a new tankless water heater installation.
Pros and Cons
Pros:
- Exceptionally durable and leak-proof design
- Includes every valve needed for a standard install
- Saves time and hassle during setup
- Wide compatibility with different heater models
Cons:
- Requires basic plumbing skills for installation
- Higher upfront cost than buying valves separately
Customer Reviews
I recently installed the Hydro Master Tankless Water Heater Valve Kit, and I’m thoroughly impressed with its performance. This kit made the installation of my tankless water heater incredibly easy and hassle-free. The valves are of excellent quality, providing a secure and leak-free connection.
I bought an electric tankless Stiebel Eltron Tempra 36pro water heater and used this heavy duty, solid brass, 3-valves set that came with the correct gaskets. The valves fit perfectly straight out of the box.
2. Under Sink Tankless Water Heater Electric 120V for Instant Hot Water in Kitchen or Bathroom
This sleek 120V unit delivers instant hot water right at your sink. Its smart design adjusts power based on flow, saving energy without sacrificing performance.
Key Features That Stand Out
- ✓ Frequency conversion technology for automatic power adjustment
- ✓ Ultra-thin, compact design fits easily under most sinks
- ✓ Multiple safety features including memory function and alarm alerts
- ✓ Energy-efficient operation reduces electricity use
Why We Recommend It
We love its intelligence and safety. It heats water on demand and protects itself from faults, making it a reliable choice for daily kitchen or bathroom use.
Best For
Best for anyone tired of waiting for hot water at a remote sink, especially in older homes with slow plumbing runs.
Pros and Cons
Pros:
- Very compact and easy to install in tight spaces
- Smart energy-saving features lower operating costs
- Provides truly instant hot water
- Good safety protections for peace of mind
Cons:
- May not handle very high flow rates simultaneously
- Installation requires access to a 120V outlet
Customer Reviews
I’ve just unboxed the 6.5KW Tankless Water Heater Electric for our kitchen, aiming to solve the slow hot water issue in our old house. Though not yet installed, first impressions are promising. Its compact and sleek design seems perfect for our kitchen’s limited space.
The heater’s promise of instant hot water is exactly what we need. The design looks durable and intelligent, which gives me confidence in its performance.
3. Ranein 4-Gallon 120V Electric Mini-Tank Water Heater for Instant Point-of-Use Hot Water
This mini-tank heater is a cost-effective way to get instant hot water. It holds 4 gallons, so you have a small reserve, and heats rapidly with high efficiency.
Key Features That Stand Out
- ✓ 1440W molybdenum-gold heating rod with 99% thermal efficiency
- ✓ Compact design (20″x10″x10″) fits neatly under sinks
- ✓ Simple installation with standard 1/2″ NPT connections and a 43″ power cord
- ✓ Energy-efficient operation for lower utility bills
Why We Recommend It
It offers great value. You get the benefit of a small tank for immediate use and efficient reheating, all at a very affordable price point.
Best For
Best for budget-conscious buyers who need reliable point-of-use hot water for a single sink and want to avoid wasting water.
Pros and Cons
Pros:
- Excellent price for the features and performance
- Very energy-efficient heating technology
- Easy to install with included hardware
- Provides hot water immediately from the small tank
Cons:
- Limited to 4-gallon capacity before needing reheating
- Takes up slightly more space than pure tankless models
Customer Reviews
This water heater delivers hot water immediately, which is a huge upgrade. I was waiting for minutes to get hot water from the household hot water heater. The entire family complained about wasting water, so I got this unit. I did choose the 4-gallon model, and it’s perfect.
Doing exactly what it is supposed to do after 2 months. Easy to read temp display, hot water always in the tank does a decent job of heating it after the tank is empty. Very pleased with the unit so far.
4. SIVUATEK 240V 14kW Electric Tankless Water Heater for On-Demand Hot Water in Your Home
Note: This is a 240V model, but we include it for comparison. It’s a powerful unit for whole-house or point-of-use applications, offering endless hot water with smart controls.
Key Features That Stand Out
- ✓ 14kW power for strong, consistent hot water flow
- ✓ Smart technology adjusts power based on flow rate and temperature setting
- ✓ User-friendly digital display and touch controls
- ✓ Compact design suitable for various installation spots
Why We Recommend It
We recommend it for its power and intelligence. It can handle higher demand, and the real-time adjustments make it efficient and convenient.
Best For
Best for homes with 240V service that need a reliable on-demand water heater for a kitchen, bathroom, or even a small apartment.
Pros and Cons
Pros:
- High power output ensures ample hot water
- Energy-efficient with smart modulation
- Easy to use with digital interface
- Durable and well-built for long-term use
Cons:
- Requires 240V electrical wiring, not standard 120V
- May need professional installation due to higher power
Customer Reviews
Update: if power goes out, it stays off. So best to install where you can easily access the front panel to turn it on again. Mounting was a breeze with included template and brackets. My water is around 85 F coming in, so there was no reduction in flow at the kitchen sink.
Bought this to replace an older one. It works better than the Marley we had for years!
5. Rheem 3.5kW 120V Point of Use Thermostatic Tankless Electric Water Heater
From a trusted brand, this 120V tankless water heater offers precise temperature control. It’s perfect for low-flow applications like a bathroom sink or wet bar.
Key Features That Stand Out
- ✓ Thermostatic controls in 1-degree increments from 80°F to 140°F
- ✓ Compact size saves space under sinks or in small cabins
- ✓ Requires a 30-amp double pole breaker for 120V hardwired installation
- ✓ Designed for consistent, on-demand hot water
Why We Recommend It
We recommend it for its reliability and precise control. Rheem is a known name in water heating, and this model delivers steady performance for point-of-use needs.
Best For
Best for installations where precise temperature is key, such as in an office breakroom, garage sink, or auxiliary bathroom.
Pros and Cons
Pros:
- Accurate temperature adjustment for comfort
- Compact and space-saving design
- From a reputable, trusted brand
- Provides consistent hot water on demand
Cons:
- Hardwired installation may require an electrician
- Limited to low-flow applications only
Customer Reviews
I’ve installed three of these, and all have worked flawlessly. One of them provides adequate hot water for a small home (2 adults) having a shower, lavatory, kitchen sink, dishwasher, and clothes washer. Although it can draw up to 46 amps, the 100 amp main breaker has never tripped.
There are many factors to consider before buying an electric tankless heater. By far the most important is whether the ground water temperature in your area is consistently warm enough. I live in North Central Florida where the ground water is warm, and this unit works perfectly.
6. 3kW 120V Under Sink Tankless Water Heater with Digital Display and Thermostatic Control
This straightforward 3kW unit is designed for simple under-sink use. It has a clear digital display and is built with safety in mind for reliable instant hot water.
Key Features That Stand Out
- ✓ Enlarged LED digital display with easy knob control
- ✓ Multiple protective features including overheat and dry burn protection
- ✓ Designed specifically for low-flow use at a single tap
- ✓ Compact and easy to install in confined spaces
Why We Recommend It
We recommend it for its simplicity and safety. It’s a no-fuss option that does one job well: providing hot water for a sink without complicated settings.
Best For
Best for a kitchen or bathroom sink where you need basic, reliable hot water for washing hands or dishes, and not for showers.
Pros and Cons
Pros:
- User-friendly with a clear digital display
- Good safety protections for worry-free operation
- Affordable and easy to operate
- Compact size fits under most sinks
Cons:
- Not suitable for showers or high-flow applications
- Some users report variability in performance
Customer Reviews
These are awesome, you should check your water heater every once a month, and flush it, and will only use one of these a year, but this Brand is good so far!!
This small 110 volt under counter tankless heater does not work at all. I had to send it back and get a 2.5 gallon electric tank style to make it work.
7. Bosch ES4 4-Gallon 120V Electric Mini-Tank Water Heater for Wall or Floor Mounting
A classic mini-tank model from Bosch, this 4-gallon heater is versatile and long-lasting. It plugs into a standard 120V outlet for easy point-of-use hot water.
Key Features That Stand Out
- ✓ 4-gallon capacity with high thermal efficiency for quick recovery
- ✓ Premium glass-lined tank for durability and long service life
- ✓ Can be wall-mounted or placed on the floor for flexible installation
- ✓ 36-37″ power cord plugs into a 120V outlet
Why We Recommend It
We recommend it for its proven reliability and flexibility. Bosch is a trusted name, and this heater is built to last, making it a solid investment.
Best For
Best for those who want a simple, plug-and-play solution with a small buffer tank, ideal for under-sink installation in homes or cabins.
Pros and Cons
Pros:
- Very reliable and durable construction
- Easy to install with plug-in operation
- Flexible mounting options
- Good for reducing water waste while waiting for hot water
Cons:
- Tank takes up more space than pure tankless units
- Limited to 4 gallons before needing reheating
Customer Reviews
So far it’s working great, I mounted it in the crawl space under the kitchen sink and put it inline with the hot water pipe that feeds the kitchen sink. No more wasting water during a long wait for the hot water to get there. I timed it and I’m now getting hot water in 6 seconds. This is the 4 gallon model.
Bought this 5 years ago and placed under sink in my outdoor kitchen. It has worked well providing hot water when needed. Generally I don’t run out of hot water. If I use hot water for an extended period of time, it does not take long to heat up the next batch. Getting ready to purchase another for under a different sink.
8. 8-Gallon 120V Electric Under Sink Water Heater for Instant Hot Water in RVs or Kitchens
With an 8-gallon capacity, this mini-tank heater is great for larger demands. It heats water rapidly and is built with a sturdy stainless steel tank for durability.
Key Features That Stand Out
- ✓ 8-gallon capacity for more hot water reserve
- ✓ Rapid reheat technology minimizes wait time
- ✓ 1.88mm thick stainless steel tank for longevity
- ✓ Safety features like leakage protection and auto temperature control
Why We Recommend It
We recommend it for its larger capacity and robust build. It’s perfect for situations where you need a bit more hot water, like in an RV or a busy kitchen.
Best For
Best for RVs, cabins, or kitchen setups where you need a reliable hot water source with a larger reserve than standard 4-gallon models.
Pros and Cons
Pros:
- Larger capacity reduces frequency of reheating
- Durable stainless steel construction
- Good safety certifications for reliable use
- Suitable for both residential and mobile applications
Cons:
- Bulkier due to the larger tank size
- May require more space for installation
Customer Reviews
We tried a small instant water heater from Amazon and since that didn’t work so well, we replaced it with this unit. We’ve had this unit for a few weeks now and it’s a game changer!!!! The water is so hot, I actually needed to turn it down. We have it in a Tiki Bar by our pool and control it with a remote.
I installed this in my boat and it worked flawlessly all summer. Easy installation and instant hot water.
9. 3000W 110V Electric Tankless Water Heater with Digital Display for On-Demand Hot Water
This 3000W (110V) model is designed for efficiency and safety. It has a sleek appearance and multiple protections for worry-free on-demand hot water.
Key Features That Stand Out
- ✓ 3000W power with a clear LED display for easy monitoring
- ✓ Ultra-thin, smooth design that looks elegant under sinks
- ✓ Multiple safety functions: water and electricity isolation, IPX4 waterproofing
- ✓ Compact and efficient for point-of-use applications
Why We Recommend It
We recommend it for its balance of power and safety. It’s a good mid-range option that delivers consistent performance for daily tasks.
Best For
Best for under-sink installation in homes or small businesses where you need a reliable, safe heater for washing dishes or hands.
Pros and Cons
Pros:
- Good power output for a 110V unit
- Attractive and compact design
- Strong safety features for protection
- Easy to use with digital controls
Cons:
- Performance can vary with incoming water temperature
- Some users report inconsistent water heating
Customer Reviews
Satisfied with this water heater. I installed it under my sink and it works perfectly. It heats the water quickly and keeps the temperature stable. It’s compact, doesn’t take up much space, and was easy to install. For daily tasks like washing dishes or hands, it’s more than enough. Very happy with the purchase.
DO NOT BUY! If you’re expecting to have consistent hot to warm water for ANY type of use, this is not for you. It will give you about 1 second of hot water and then nothing but cold tap water after. Bought this to use under a shop sink, only wanting hot water to wash a dish or two. Will be returning.
10. Under Sink Tankless Water Heater Electric 120V for Instant Hot Water in Kitchen or Bathroom
Similar to product 2, this 120V tankless heater offers smart energy-saving features. It’s designed for safety and reliability, providing instant hot water where you need it most.
Key Features That Stand Out
- ✓ Frequency conversion design adjusts power automatically
- ✓ Safe, intelligent, and ultra-thin appearance
- ✓ Memory function and automatic alarm for fault detection
- ✓ Energy-efficient operation reduces electricity consumption
Why We Recommend It
We recommend it for its intelligent features and safety. It’s a solid choice if you want a modern heater that adapts to your water usage.
Best For
Best for kitchen or bathroom sinks in homes where energy efficiency and smart technology are priorities.
Pros and Cons
Pros:
- Smart energy-saving technology
- Compact and sleek design
- Good safety features for reliable operation
- Provides instant hot water on demand
Cons:
- May have limited flow rate for multiple uses
- Installation requires proper electrical setup
Customer Reviews
I’ve just unboxed the 6.5KW Tankless Water Heater Electric for our kitchen, aiming to solve the slow hot water issue in our old house. Though not yet installed, first impressions are promising. Its compact and sleek design seems perfect for our kitchen’s limited space.
The heater’s promise of instant hot water is appealing. The intelligent design and safety features make it a worthwhile consideration for upgrading our hot water system.
Complete Buying Guide for Best 120 Volt Tankless Water Heater
Essential Factors We Consider
When picking a 120 volt tankless water heater, focus on flow rate, power rating, and installation ease. Flow rate tells you how much hot water it can deliver per minute—important for your needs. Power rating in watts or kW affects heating speed; higher power means hotter water faster. Also, check safety features like overheat protection and whether it’s plug-in or hardwired. Look for energy-efficient models to save on bills.
Budget Planning
120 volt tankless water heaters are generally affordable, but prices range from budget to premium. Set a budget that includes the unit and any installation costs. If you’re DIY-savvy, you can save on labor. Remember, a slightly more expensive model with better efficiency might save you money long-term on electricity. Don’t forget to factor in potential electrical upgrades if needed.
Final Thoughts
Always match the heater to your specific use—like a kitchen sink or RV. Check compatibility with your plumbing and electrical system. Read reviews and compare features. A well-chosen tankless water heater can provide convenience and savings. Take your time to find the right fit for your home.
Frequently Asked Questions
Q: Can a 120 volt tankless water heater run a shower?
A: Most 120 volt models are designed for point-of-use like sinks, not showers. They typically don’t have enough power for the high flow rate of a shower. For showers, you usually need a 240 volt unit or a dedicated point-of-use heater with sufficient capacity.
Q: How difficult is installation?
A: Installation varies. Some models are plug-and-play for under-sink use, just needing a 120V outlet. Others require hardwiring by an electrician. Always follow the manual and check local codes. If unsure, hire a professional to ensure safety.
Q: Are tankless water heaters energy efficient?
A: Yes, they are generally more efficient than tank heaters because they only heat water when you turn on the tap. This eliminates standby heat loss. Look for models with energy-saving features like modulation to maximize efficiency.
Q: What maintenance do they need?
A: Maintenance is minimal. For areas with hard water, descaling annually can prevent mineral buildup. Check for any leaks or error codes periodically. Most units have self-diagnostic features to help.
Q: Can I use it in an RV?
A: Absolutely! Many 120 volt tankless or mini-tank water heaters are perfect for RVs due to their compact size. They provide instant hot water without the bulk of a traditional tank, making them ideal for mobile living.
Choosing the best 120 volt tankless water heater can make your daily routine smoother and more efficient. From our top-rated Hydro Master valve kit to budget-friendly mini-tanks, there’s an option for every need. We’ve tested these models for performance, safety, and value. Ready to enjoy instant hot water? Check out our top picks and find the perfect match for your home today!

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