Best Under Sink Water Heaters
Review and Buying Tips

Why under sink water heater is a good solution for your home hot water needs? Find top models to buy for point of use service with the main features. Check out the best selling tank-type and tankless models and buying tips for the worry-free shopping experience.

The under sink water heater, such as this Bosch Tronic 3000, is a small electric appliance designed for instant water heating/delivery at home, office, condo, apartment, cottage, garage, RV, boat and at the point of service. It is also known as an instant water heater for the sink, or under counter water heater, where the main advantages include space, water, and energy savings when properly installed and used.

It works perfectly as a single unit, combined with the distant whole-house tank-type unit or installed in-line with an existing tankless water heater, as a buffer, reducing the "cold water sandwichi" effect, delivering hot water fast.

Advantages and benefits

There are two types of under sink water heaters that can be purchased; tank-type such as the Bosch mini-tank Tronic and tankless type such as Ecosmart or Stiebel Eltron that come with less power than the whole-house models, but sufficient to heat and deliver water to one fixture/sink.

Tankless type does not contain the water storage tank but is providing an endless supply of hot water, while the tank-type has a limited capacity.

One of the greatest advantages of under sink water heaters is instant hot water delivery saving time, energy and money. This way you don't have to run long pipes from the central water heater; just plug this small water heater close to the faucet and enjoy an instant water delivery with the temperature that does not differs from the set one.

By buying a high quality under sink water heaters as listed and reviewed here, the homeowner will enjoy the following benefits:

  • Heating cost reduction up to 50%, including energy and water consumption.
  • The unit saves you money as it eliminates the need for expensive recirculating lines or pumps.
  • Under sink water heater saves water efficiently as it is used where it is needed, at the point of use; kitchen sink, bathroom, laundry, garage, small cabins, boats and RVs, offices...
  • The product serves one or two faucets max. mainly for doing dishes, hand washing or shaving.
  • You can choose one of the two different types; tank-type or tankless. Tank type has a limited tank size, usually from 2 gallons while tankless provide an unlimited water supply but with the restricted flow. Tankless models are heating water instantaneously as it flows through the unit and there is no standby heat loss.
  • Under sink water heater is a small, lightweight and compact unit that doesn't occupy too much of the space.
  • It’s easy to install since it comes with the quick installation guide.
  • They can be wall mounting or floor standing.
  • The product is very reliable, safe and energy efficient.
  • It has a compact body and other easy-to-use features.
  • They offer a safety feature for the reliable and safe operation.
  • The desired temperature of the outgoing water can be set by using the temperature dial.
  • Cheap to buy.

Popular under sink water heaters to buy

EcoSmart ECO 11

Ecosmart Eco 11Ecosmart Eco 11

EcoSmart ECO 11 is a tankless electric water heater that utilizes one high power heating element, designed to provide up to 13 kW of heating power, and thanks to the advanced self-modulating technology, able to control how much of energy will be used at certain the point of time.

The unit utilizes a control panel with the adjustment knob/temperature control so the users can easily set the temperature between 80 F and 140 F and the digital temperature display to check and monitor.

Due to its small size of 11.5" x 8" x 3.75", lightweight design of 6.5 lbs, wall mount installation and water delivery of up to 2 GPM, the EcoSmart water heater is ideal for small homes and apartments - or point of use applications.

Looking at the user reviews, they were mainly positive (4.2 of 5). Users were happy with the performance of the unit, consistent temperature of the outgoing water and savings. For the proper work and avoid hassle and failure, it is recommended to have all the electrical requirements met. As some users suggested, hot water is possible to get, but the water flow has to be reduced and incoming water not too cold, otherwise, it wouldn't be high as expected. The unit is small, easy to install, even replace the elements.

EcoSmart ECO 11 is a good buy, not only because of its great features, fancy look and small size, but because it saves energy (up to 50%), lifetime warranty and positive user feedback.

Bosch Tronic 3000 T

Bosch Tronic 3000Bosch Tronic 3000

Bosch Tronic 3000 T - model ES2.5 is one of the top-selling electric mini tank-type water heaters that are designed for installation under the sink or in cabinets, in small apartments, RVs, and boats, garages...

Here are the main features:

  • Attractive and modern look.
  • Small (13.75 " x 13.75" x 10.75") and lightweight (15.5 lbs) design.
  • Except for the single installation, it can also supplement a large tank-type water heater, to deliver water fast or in-line with the tankless unit for the continuous supply.
  • Simple 120 V plug-in connection.
  • Flexible, floor, shelf or wall mount installation.
  • It is equipped with the external dial for temperature control from 65 F to 145 F.
  • It uses one heating element with the power of 1440 W. Recovery rate is 6.8 gallons per hour.
  • 6-year warranty.

Pros and Cons. Bosch Tronic 3000 T is a great solution for people who are looking to avoid long wait time from the distant water heater. It comes with a good manual which makes the hook-up simple. The heater requires a dedicated electrical outlet. Hot water from 2.5-gallon tank doesn't last long (few minutes only), but it is good enough for small jobs such as hand and face washing - and it takes less than 10 minutes to warm it up again.

Buying tips

When looking to buy a quality under sink water heater, first check out the popular and well-known brands that have a good reputation and years of experience, such as; Bosch, Ecostar, Stiebel Eltron, Rheem...

Also, take into consideration the following:

  • Water flow rate (bathroom faucet allows an average 0.5 gpm; shower 1.5 to 3.0 gpm)
  • Incoming groundwater temperature
  • Recovery rate
  • Activation flow rate
  • Heating power in kW
  • Available features such as the modulation, conveniently located thermostat, a relief valve for safety
  • Price and warranty

And of course, make sure that your home has all the necessary hookups, and it meets the electrical requirements for the installation of the electric water heater.


Under sink water heater is a good buy for those homeowners who need hot water delivered fast, mainly for smaller water jobs such as hand washing or dishes, as it saves time, water and energy.

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