Hot water on demand: our guide to the best undercounter water heaters (2023)

ThroughStefan Gheorghe🇧🇷 posted on

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Bosch Tronic Mini Electric Water Heater

ECOTOUCH Flow Heater

Electric thermos with mini tank Camplux ME25 2.5

EM-7.0 Eccotemp 7 Gallon Electric Storage Water Heater

1 gallon HS-4 water heater

Hot water on demand: our guide to the best undercounter water heaters

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You know those cold winter days when you definitely don't need cold water? No more agony of wringing your hands under the icy stream of tap water. This, of course, only if you have a suitable heater in the house. For an instant hot water source, consider aUnder sink water heater.

Hot water on demand: our guide to the best undercounter water heaters (6)

Don't just take our word for it, read on. Below is our carefully researched list of high performance water heaters. they will fit perfectlyunder the kitchen countersink or bathroom cabinet. And to make sure you're making an informed decision, we've put together a list of resources to consider. Use our guide to better understand what makes alarge under sink water heater.


Using an under-counter water heater

If your current water heater is overwhelmed by your needs, you need to upgrade. But that doesn't necessarily mean replacing it. You can increase the amount of hot water available with aKettle under the sink.It is an affordable alternative to meet your hot water needs.

An undercounter water heater is an electrical device that supplies hot water directly to the faucet. As the name suggests, they are usually mounted under a sink. They can also be called point of use (THROUGH) Kettle. They generally work by heating the water as it flows. Tank-type models preheat a certain amount of water and store it until it is needed.

Reduce waiting time with abench heater🇧🇷 These devices are designed to deliver abundant hot water in seconds. And they even fit in your boat, RV, office, or garage. You choose the place, these heaters fit perfectly.

However, undercounter instantaneous water heaters are not a replacement for your large heater. For the best results, you should combine them. Connect the under sink unit to your shower or faucet, or use it in conjunction with your main heating system. The use of these small devices brings advantages such as saving water, energy and space.

What should you consider with an under sink instant water heater?

There are a few important features that can make all the difference in an undercounter heater. To find out what works best for your needs, space, and budget, check out the list below.

  • model

The decision between a tankless or a tank model depends on your needs. Tankless water heaters are more expensive, but they won't keep you waiting. They take up very little space and meet your hot water needs almost instantly. On the other hand, if you want to have hot water in various corners of your house, the version with a tank is more suitable. this way youenjoy your hot bathin the back room without disturbing variations.

  • flow ratio

If you need a steady flow of hot water, your undercounter water heater should have a high GPM (or GPH). The number of gallons per minute (gallons per minute) or gallons per hour (GPH) indicates the amount of hot water the unit can deliver.

  • Energy Rating

You'll enjoy constant hot water, but high electric bills can be a liability. The energy rating indicates the ability of the heater to consume little energy. The higher the energy efficiency class, the less energy is used to heat a large amount of water.

  • Dimensions

Space is at a premium, so make sure you make the most of it. As you can imagine, an undercounter tank water heater takes up more space. Tankless versions are much more practical and can go unnoticed even in tight spaces. Before you buy, take some precise measurements of your available space.

  • heating capacity

To get the best performance from your water heater, balance demand with capacity. Think about the amount of hot water you will probably need at any given time. Consider how long it will take for the device to heat more water once the supply runs out. Simply put, the hot water you use is usually quickly replaced with cold water in the heater. Usually it only takes a few minutes to heat the cold water. However, if you anticipate a high demand for hot water (with a large family, for example), look for a heater that can provide it in a timely manner.

  • Voltage

When choosing a heater, make sure the outlets in your home (or boat, trailer, etc.) can handle the need. Most devices work fine when plugged into 120V outlets. For heaters that require 220V, for example, you need to adapt your outlets. See model electrical requirements for more information.

  • security devices

Additional features are always a great thing. For undercounter water heaters, this includes a thermostat, modulating, or pressure relief valve. A thermostat makes it easy to control the water temperature. Modulating means adjusting the heating output in response to the flow of water through the unit. A pressure relief valve prevents damage from excessive water pressure.

  • instalation and maintenance

Perhaps you are the handyman type or would prefer to call in a professional to help you with this. Take a look at the installation requirements to get an idea of ​​the process. Some devices only need to be plugged into a power outlet to work. Others may indicate that electrical or plumbing work is being done. This is important to comply with the warranty conditions. When it comes to maintenance, you want to make sure you can use and care for your heater properly to extend its life.

  • To guarantee

Better safe than sorry means weighing the risks that may arise early. A long-term warranty on your undercounter water heater can give you peace of mind. Especially if you invest a constant amount of money. Warranty conditions vary from manufacturer to manufacturer. An extended warranty period is a strong indication of longevity. Some models even come with a lifetime warranty.

Our 6 Most Recommended Undercounter Water Heaters

ProductsDoesmodelflow ratioheating capacityDimensionsTo guarantee
1. Bosch Tronic 3000 T 4 Gallon Mini Electric Water Heater (ES4)durable design; best for low hot water demand4 gallon tank6,8 GPH1.440W13.75x13.75x13.5 inches6-year device warranty, 2-year parts warranty
2. Flow heater ECOTOUCH flow heaterself-modulating technology for optimal energy efficiencyno tank120 GPH
(2 GPM)
13000W3.75x8x11.5 incheslifetime warranty
3. Flow heater ECOTOUCH flow heatervarious security features; Touch control panel for temperature settingsno tank90 GPH (1,5 GPM)5500W11 x 7.5 x 2.35 inchesUndefined
4. Camplux ME25 Mini Tank 2.5 Electric Water Heater<suitable for caravans and caravans; versatile installation options2 gallon tank6,8 GPH1500W11,75x17,25x10,381 year warranty
5. Eccotemp EM-7.0 7-Gallon Electric Storage Water Heaterideal for different settings (boat, food truck, RV); Easy to use7 gallon tank135 GPH1440 watts17.2 x 17.2 x 14.2 inches2-year parts warranty, 5-year leak warranty
6. HS-4 1 Gallon Electric Instant Water Heaterbuilt-in timer; Adjustment of energy consumption based on real-time datano tank120 GPH
(2 GPM)
3200 watts6.5 x 11 x 3 inches5 year warranty

1. Bosch Tronic 3000 T 4 Gallon Mini Electric Water Heater (ES4)

Hot water on demand: our guide to the best undercounter water heaters (7)view gallery

oBosch Tronic 3000 T 4 Gallon Mini Electric Water Heater (ES4)it is a time saver. If your main heat source is far from the sink, it can take a while to get hot water. Time is money and Tronic 3000 T knows it. This POU electric heater is a perfect device for multiple applications. Use it as a standalone hot water source for a sink or as a supplement to your main heating. It also works as a buffer in line with other heaters that don't provide a constant flow of hot water. Forget about the sensations of heat and cold. Count on this undercounter water heater to provide hot water when and where you need it.


  • compact and lightweight design
  • CFC-free foam insulation: energy efficient
  • made of durable materials
  • versatile installation options
  • enamel tank.


  • limited warranty (6 years)
  • reduced capacity for hot water flow
  • Some users blamed leaking issues after a few months of use.

2. EcoSmart ECO 11 water heater

Hot water on demand: our guide to the best undercounter water heaters (8)view gallery

oEcoSmart ECO 11 electric instantaneous water heaterstands out from the crowd. The device controls output power using patented automatic modulation technology. Therefore, you can rely on them to ensure optimal water heating. This under counter water heater can provide enough power for up to two sinks and one shower at the same time. Its performance varies based on the average water temperature in your area. In colder climates, the ECO 11 only provides enough hot water for two sinks at a time. Perfect for use in a small apartment or as a small point of use, this undercounter heater is capable of delivering up to 2 gallons of hot water per minute. With 99.8% energy efficiency and a lifetime warranty, this device is a great addition to any home.


  • high energy efficiency class
  • digital temperature control
  • self-modulating technology
  • lifetime warranty
  • small size and compact design.


  • it requires more time to provide hot running water in colder climates.

3. Flow heater ECOTOUCH flow heater

Hot water on demand: our guide to the best undercounter water heaters (9)view gallery

oECOTOUCH Flow Heater turns "warm" water into a memory. With a 5.5KW heating system, this undercounter water heater can provide hot water to your sink instantly. No preheating, no temperature fluctuations. The device features intelligent auto-adjustment based on real-time flow rate and temperature settings. It fits perfectly in your sink and guarantees a constant flow of water at the ideal temperature.


  • Digital display and touch control panel
  • Easy to use
  • ETL and UL Listed
  • compact design
  • 360 degree installation options
  • over temperature protection
  • dry heater protection
  • leak protection
  • Separate water and electricity line.


  • There is no remote control for this model.
  • Professional installation may be required for warranty security.
  • not for use in the shower.

4. Camplux ME25 Mini Tank 2.5 Electric Water Heater

Hot water on demand: our guide to the best undercounter water heaters (10)view gallery

oCamplux ME25 Mini Tank Electric Water Heaterit is a versatile and easy to install POU. Suitable for shelf, wall, or floor mounting, this unit features a glass-lined tank that is built to last. Enjoy 2.5 gallons of hot water when you need it. With a CSA listed temperature/pressure relief valve, this model is very safe to use.

You can install it without much effort. Just tap the cold water line under the sink and plug the unit into a 120V source. And instantly you have an efficient, energy-saving water heater.


  • easy to install
  • overheat protection
  • enamel tank
  • multiple installation options
  • fast recovery rate.


  • one year warranty.

5. Eccotemp EM-7.0 7-Gallon Electric Storage Water Heater

Hot water on demand: our guide to the best undercounter water heaters (11)view gallery

oEM-7.0 Eccotemp 7 Gallon Electric Storage Water HeaterIt is ideal for any residential, commercial or industrial area. This under counter water heater can provide hot water to any faucet in no time. Compact and lightweight, it fits anywhere you need it. Take it on your boat, trailer, food truck, or use it as a supplement to your home's main heating.


  • easy to install
  • 98% efficient energy recovery
  • payable price
  • accessible temperature controls.


  • no thermostat
  • without stop valve
  • limited warranty.

6. HS-4 1 Gallon Electric Instant Water Heater

Hot water on demand: our guide to the best undercounter water heaters (12)view gallery

o1 gallon HS-4 water heaterIt's the waterproof stainless steel heater you've been looking for. Setting the desired temperature is easy thanks to the interactive touch panel. With a temperature range of 80°F to 140°F, you know this device will protect you from both heat and cold. This undercounter water heater will know your preferences very well. It is based on excellent closed-loop modulation and a quarter GPM trigger flow rate. This means that the heater adjusts the energy consumption based on the frequency of use of the heater. Using real-time data, this device has high energy-saving performance.


  • no ventilation required
  • digital temperature indicator
  • thermostat included
  • built-in timer
  • efficient energy consumption.


  • only suitable for a kitchen sink
  • limited warranty.

Pros and cons of under sink water heaters

Every purchase decision must have a solid base to argue. So here are the main pros and cons of using an undercounter water heater in your home or boat, trailer, etc.


  • to save time– Reduced waiting time to get the hot water you need
  • save water– Less waste of water in the heating process, since the devices supply heated water directly.
  • comfort improvementin large houses: it can supplement the main heating source and provide hot water to remote areas of the house
  • efficient energy– low energy consumption in relation to the power level


  • rising utility bills– although the latest models have a high consumption-performance ratio, you will feel their “presence” in your bills, since they require significant resources
  • maintenance costs– You should regularly check for leaks and lime deposits, as they can compromise the integrity of the oven and its safety during use
  • significant investments– Some models can be very powerful but require a bigger budget to buy one

take care of yoursunder the sinkKettle

As with any appliance, optimal use can extend the life of your appliance. To keep your undercounter water heater in good shape, you should consider some regular checkups. It is important to keep your water heater in good condition to avoid additional repair costs.

among the things you can dokeep your water heater running smoothly, consider:

  • Checkapressure relief valvesto avoid overuse.
  • Lavarto prevent limescale buildup in your POU water heater. We recommend that you do this at least every 12 months.
  • Checkthroughleaksregularly.
  • Make sure the controls andthermostatssonworks correctly.
  • hold on tightso hesessions.

You can do this maintenance yourself or ask a professional for help. This helps minimize the risk of damage or injury associated with the use of an undercounter water heater.

final thoughts

An undercounter water heater can be a great addition to your home or vacation vehicle. Compact, powerful and energy efficient, they supply hot water as needed, thus saving time, water and energy. Read our guide and list of recommended point of use heaters. Find one that fits your space, needs, and budget. And tell us about your experience with an undercounter water heater.

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