Best Under Sink Water Heater Reviews

If the expense of replacing an outdated water heater is an issue, then installing a point of use water heater that goes under the sink might be the answer. Point of use water heaters are available as tankless and mini-tank units. These water heaters are small enough to fit underneath the kitchen sink or in a cabinet to provide a means for hot water instantly.

Because there are many water heater point of use systems available, we’ve created this list of the top models from which you can choose. When you want hot water on demand, these mini water heaters provide high-quality results. So, if you have a small apartment or want a water heating system in a spare bedroom, these systems help solve them.

Read more about the options for under the sink water systems.

Bosch Water Heater Tronic 3000 T 4-Gallon (ES4)
  • Tank volume: 4 gallons
  • Recovery flow rate: 6.8 GPH
  • Water pressure range: 150 PSI
EcoSmart ECO 11 Electric Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology
  • Tank volume: Tankless
  • Recovery rate: 2 GPM
  • Water pressure range: 25 to 150 PSI
Thermoflow UT10 2.6-Gallons Water Heater for Under Sinks, 1.5kW at 120 Volts
  • Tank volume: 2.6 gallons
  • Recovery flow rate: 0.5 GPM
  • Water pressure range: 115 PSI
Camplux ME25 Electric Hot Water Heater 2.5-Gallon,1.5kW at 120 Volts
  • Tank volume: 2.5 gallons
  • Recovery flow rate: 6.8 GPH
  • Water pressure range: 150 PSI
Ariston GL6+S Water Heater
  • Tank volume: 7 gallons
  • Recovery flow rate: 6.8 GPM
  • Water pressure range: 150 PSI

Top Under Sink Water Heaters

Are you looking for a water heating system that doesn’t take up much room and delivers instant hot water? If you have an outdated system, you’ll find that these units are particularly beneficial. The Bosch Heater Tronic 3000 T 4-Gallon (ES4) is available in three sizes, each that are easy to install on the floor, under the sink, or on the wall.

There’s also the option of installing these hot water heaters in-line with a traditional hot water heating source to help reduce the time you have to wait. Keep in mind that even though these water heaters can be installed on the floor, the curved bottom means you must have a stabilizer.

With this system featuring a compact and lightweight design, this hot water heater is also constructed with a glass-lined system. Not only does this feature extend this unit’s life, but it also helps to prevent corrosion. There’s also a layer of CFC-free foam that provides the best energy efficiency. Its compact size means this hot water heater is easy to install and can fit underneath your sink. 

Product description:

  • Convenient four-gallon point of use compact system
  • CFC-free foam insulation
  • Includes 36 to 327″ cord that plugs easily into a standard outlet


  • Voltage: 120 V
  • Temperature range: 65 to 145°F
  • Pressure relief valve attached for drainage
  • 6-year warranty on the unit after registering with your email
  • 2-year warranty on parts

Technical specs:

  • Dimensions: 13.75 x 13.75 x 13.5 inches
  • Tank volume: 4-gallon tank
  • Recovery flow rate: 6.8 gallons of water per hour (GPH)
  • Water pressure range: 150 pounds per square inch (PSI)
  • Weight: 17.4 pounds


  • Excellent for small uses during everyday activities
  • Energy efficient with glass lined tank
  • Easy to install and utilize
  • You do not have to wait for a very long time for hot water
  • It stores leftover hot water from the faucet


  • It’s difficult to determine the temperature of the water because the thermostat is too simplified
  • It isn’t possible to mount these water heaters on the floor because the bottoms are curved

Suppose you’re looking for an energy-efficient system to supplement your existing hot water heater. In that case, the EcoSmart ECO 11 Electric Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology, is an excellent solution. Using this hot water unit helps you save up to 60% on your hot water heating costs. That’s a significant amount of savings regarding how much it typically costs to heat water in a home.

Thanks to ECOSMART’s tankless design, these water heaters are 99.8% energy efficient with a Uniform Energy Factor of 0.98. These tankless water heaters are a good option if you’re looking for a high-performance unit that saves you money. These systems fit into any small space as long as the pipe and 120 V connections are available.

In addition to its compact and sleek design, this hot water heater also features a digital thermostat to help you see the water’s exact temperature. That’s beneficial for those who want to know that the hot water in the system is precise. 

Product description:

  • Patented self-modulating technology
  • Uniform energy factor of 0.98
  • Ideal for small apartments or small point of use applications


  • Voltage: 240 V
  • Temperature range: 80 to 140 degrees Fahrenheit
  • Ideal for use in weather conditions that are 67°F or above
  • Digital temperature control
  • Lifetime Warranty on electronics, element, and exchanger

Technical specs:

  • Dimensions: 11.5 x 8 x 3.75 inches
  • Tank volume: Tankless
  • Recovery rate: 2 GPM
  • Water pressure range: 25 to 150 PSI
  • Weight: 6.5 pounds


  • The light-weight and compact design makes it easy to install
  • Can handle two sinks running simultaneously
  • Energy-efficient, allowing you to save up to 60% on your hot water costs
  • Easy to read digital display on the thermostat
  • The longest warranty compared to competing models


  • The warranty doesn’t cover incidental damages or labor; it only covers the heater’s cost
  • This hot water heater isn’t ideal for large capacity hot water needs

If you’re living in a cold area, like the northern parts of the United States, having an under the sink water heater might not be ideal. The main reason is that it’s challenging to keep pipes or storage units from freezing. However, choosing the Thermoflow UT10 2.6-Gallons Mini-Tank Water Heater for Under Sinks, 1.5kW at 120 Volts is the exception.

The main reason is that this system has a mode for frost protection. If temperatures drop, that mode kicks in to help prevent the water temperature from getting too low. This system also has an energy-saver mode. The unit features a stainless steel construction complete with an ESP foam lining. That lining helps provide a means for heating water quickly, thus eliminating the energy waste from waiting for water to heat up.

The system’s “thermostop” function helps you save even more money. That function makes the unit stop heating water as soon as it reaches a set temperature. It won’t restart until you need hot water again. That can help reduce your utility bills by a significant amount. 

Product description:

  • Stainless steel design
  • Advanced “thermostop technology” prevents low standby power consumption
  • Safe installation thanks to the active protection circuit


  • Voltage: 120 V
  • Temperature range: 45 to 167°F
  • Easy to use plug-in design
  • Water relief valve included
  • 1-year labor and parts warranty

Technical specs:

  • Dimensions: 18 x 12.2 x 11 inches
  • Recovery flow rate: 0.5 GPM
  • Water pressure range: 115 PSI
  • Weight: 8.4 pounds


  • Overheat protection means it automatically stops heating or reheating water once it reaches a high or low-temperature setting
  • Affordable price
  • EPS foaming technology allows for a fast recovery rate
  • Minimal standby hot water loss
  • Specially designed for point of use underneath your sink


  • Some consumers find this hot water system challenging to install and may require a plumber
  • This hot water heater may require several different sized pipes and wires

If you and the rest of your family love spending time in the great outdoors, then the Camplux ME25 Electric Water Heater 2.5-Gallon,1.5kW at 120 Volts, is an excellent choice for your hot water needs. Whether in a boat or RV or if you want hot water in your patio kitchen, this hot water system is small enough to fit underneath the sink.

With this system featuring a 2.5 gallon capacity, this electric water heater has high-quality insulation thanks to its glass-lined tank. That means it’s easy to maintain, but this system should also last for years. We love this system because it installs easily in your outdoor settings; it can be used in your RV without any issues.

You’ll notice how efficient this unit is as it heats water at 6.8 gallons per minute. The thermostat is easy to use, as well. In addition to regulating water temperature, it helps you save energy. For example, look for a snowflake icon and, when the system isn’t in use when it’s cold, turn it to that icon. Doing so helps protect any water left in the tank from freezing. 

Product description:

  • Glass lined system makes it easy to maintain and extends lifespan
  • Overheat and freeze protection
  • High-efficiency heating element


  • Voltage: 120 V
  • Temperature range: 77 to 140°F
  • IPX24 waterproof hot water tank
  • A 43.3‘’ cord is included
  • 1-year parts and labor warranty

Technical specs:

  • Dimensions: 11.75 x 17.25 x 10.38 inches
  • Tank volume: 2.5 gallons
  • Recovery flow rate: 6.8 GPH
  • Water pressure range: 150 PSI
  • Weight: 20 pounds


  • The thermostat is easy to check
  • Freeze protection is available, which is critical if you have an RV
  • Overheat protection helps prevent fires
  • Extra protection from the pressure relief valve
  • Doesn’t require extra wiring, all you have to do is plug it in


  • The dimensions of this unit are without pipes, so you must add at least four inches
  • The warranty is too short

For those who are searching for something that is a little bit more compact that can fit into a spare or guest bathroom, the Ariston GL6+S Electric Tank Water Heater is an excellent option. While this unit sports the name Ariston, take note that it’s a Bosch product. You can still use this unit for instant hot water delivery, which makes it ideal for underneath sinks in kitchens and bathrooms. One of this unit’s most notable features is that this system can plug into a standard outlet for operation.

Despite the temperature being preset to between 105 and 113°F, you can still adjust the temperature according to your needs. Not only does that help with comfort, but it also saves you money on your utility bills. In addition to providing instant hot water, this water heater also works well when installed with a more substantial heating source.

Because this unit can hold up to seven gallons, it’s still possible to fit it into tight spaces. So, if you’re living in a smaller home or apartment, this system is a great choice. The pressure relief valve included helps monitor the water’s pressure and temperature. One of the drawbacks of this heating unit is that it can take between thirty minutes and one hour for it to recover. Pricing for this under sink water heater is just over $300.

Product description:

  • Fast recovery time
  • Mounting brackets are included
  • Adjustable thermostatic control


  • Voltage: 120 V
  • Temperature range: 65 to 145°F
  • A pressure relief valve is included
  • 6-year limited warranty for the heat exchanger
  • 1-year limited warranty for parts

Technical specs:

  • Dimensions: 14.5 x 17.5 x 17.5 inches
  • Tank’s volume: 7 gallons
  • Recovery flow rate: 6.8 GPM
  • Water pressure range: 150 PSI
  • Weight: 34.9 pounds


  • Only uses 12.5 AMPS to keep 7 gallons of water hot
  • Mounts to the wall, floor, or under the sink
  • Excellent energy efficiency
  • Easy to control the hot water temperature
  • Operates quietly


  • Can’t use it without hardwiring the unit into a 120 V outlet
  • Some consumers report not being able to hold more than five gallons

Under Sink Water Heater Buyers Guide

What Are Under Sink Water Heaters?

Under sink water, heaters are a point of use system that instantly raises the temperature of your home’s water. These units are typically installed underneath a kitchen or bathroom sink. However, some are small enough to sit on top of a counter or mount to a wall. They’re an excellent option if you want an instant water heater that doesn’t take a long time to heat cold water. You might also see these units listed as the point of use hot water heaters.

There are two ways to use an under the sink water heating system. The first way is by connecting the system to your home’s main pipeline. The second way is by choosing a system that can store your hot water. Suppose you want a tankless system that requires connecting it to the main cold water line in your home. Then, all you have to do is set the temperature you desire.

Types of Under Sink Water Heater Systems

When researching the types of under sink water heaters, the first thing you’re going to notice is that there are two types. Those types include tankless models and tank-type water heaters. The first type doesn’t require any storage, and you can receive hot water instantly. The second option means you have water storage and may have to wait for the hot water to recover. There are benefits and drawbacks to using each.

Tankless sink water heaters

One of the most notable features of tankless sink water heaters is that this water heater small is the most compact you’re going to find. That makes these systems ideal if you’re installing them where there are space limitations, like in a small apartment or an RV. The compact size also means these units are easy to install.

Because a sink tankless water heater doesn’t need any tanks, you get instant water at the faucet. These models feature high energy efficiency, easy installation, and optimal temperature control. However, because there isn’t a water tank, these water heaters aren’t optimal for households with high hot water demands.

Tank under sink water heaters

Many choose a hot water heater that features a mini tank because they’re more affordable and use less water. That means, if you don’t use some hot water, it stays in its storage system. A tank-type water heater typically has tanks that hold between 2 and 2.5 gallons of water. However, some of these systems can hold up to 7 gallons of water.

Just like a tankless hot water heater, these units are easy to use and easy to install. You can mount these hot water heaters on your floor, the wall, or beneath your sink. If you own an RV or live in a small apartment, these units are a great choice. The drawbacks include it taking longer for water to heat, and these hot water heaters take up more space.

Why Buy an Under Sink Water Heater?

The first thing you must understand is that an under sink water heater is not meant to replace a whole-house unit. Instead, these systems are designed to provide instant hot water for sink water. That means you’re using a mini hot water heater for small things, like cooking or a few dishes.

If you’re still on the fence about buying an under the sink system, you’re not alone. Let’s look at why you should buy one of these units. Purchasing a sink water heater has several benefits, including the following:

  • Quick and efficient: It’s possible to receive hot water on demand with a sink water heater. A traditional hot water heater takes several minutes to heat the water, making it less energy efficient.
  • Environmentally friendly: When you have an on-demand sink water heaters installed, that helps prevent wasting water while waiting for it to heat up. For example, you might need to run the water from your faucet for several minutes if you have a traditional hot water heater.
  • Compact size: The small size of sink waters heaters allows you to install them in any cabinet near or underneath the sink. Some of these models also mount on top of a counter, on a wall, or the floor.
  • Easy of installation: That compact size also makes sink water heaters easy to install. If you’re familiar with plumbing and DIY home improvement projects, you can tackle this project yourself.
  • High-quality water: Under the sink water heaters are the point of use systems that reduce the risk of water contamination that could occur in traditional hot water heaters. You’ll find this is especially true if installed in conjunction with a conventional unit with a filter.

How to Choose The Best Under Sink Water Heater


The water heater size is one of the most important factors you must consider. Many consumers choose these types of water heaters because they help save space. However, if you opt for a water heater with a tank, plan for it to take up more space under your sink than a tankless water heater. Don’t forget to account for space you’ll need for pipes, as well. Decide accordingly based on the amount of space available under your sink.


It isn’t uncommon for an instant hot water heater to require a lot of electricity. That means looking at your home’s power circuit and determining how much it can handle. The amount of volts an instant hot water heater requires depends on the model. For example, you might see one requiring 120 volts and others that need 240 volts.

Hot water demand

You can better decide which under the sink unit is best for you by calculating your home’s hot water use. That way, you can determine the gallons per minute the unit must provide. You’ll notice that all sink heaters have a fixed flow rate per minute for hot water. For example, the average person uses approximately 2.1 gallons of water per minute for showers that take at least 8.2 minutes.

Incoming water temperature

The temperature of the incoming water differs according to where your home is located. For example, if your home is located in the southern portion of the country, the water temperature is going to be higher than in the north. If you live in New Mexico, you aren’t going to need a water heater featuring as high of a temperature as if you live in Maine. Make sure you’re not choosing a hot water heater that is more powerful than you need, which could cause spikes in your electricity bills.


Finding the best under sink hot water heater doesn’t have to an overwhelming when you have the right information in front of you. The units are available on Amazon and other retailers. Your first step during the selection process is to ensure the unit fits into the space you have underneath your sink. Then, determine how much hot water your family is going to need and how often.

Our best recommendation is the Camplux ME25 Mini Tank Electric Water Heater 2.5-Gallon,1.5kW at 120 Volts for its insulating properties, tank volume, and recovery flow rate. A close runner-up is the EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology, because it features a lifetime warranty and is easy to install. Our third choice is the Thermoflow UT10 2.6-Gallons Electric Water Heater for Under Sinks, 1.5kW at 120 Volts for its affordability, the easy to use plug-in feature, and overheat protection.

Check out the Camplux ME25 Mini Tank Electric Water Heater 2.5-Gallon,1.5kW at 120 Volts by clicking here.

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