Home & Garden Portable Water Heaters

The Best Under Sink Water Heater

Last Updated on July 13, 2020

Best Under Sink Water Heaters: Quick List

An under sink hot water heater delivers instant hot water to your sink without having to wait up to 30 seconds for hot water to reach your point of use.  Under sink water heaters are also used in RVs, Campers and Vans to deliver hot water in a bathroom or kitchen sink for hand washing and dish washing.  Hot water simply washes better and cuts through oil, grease, grime and even germs better than cold water and produces a better soap lather.

The Best Mini-Tank Under Sink Water Heaters

Bosch Electric Mini-Tank Under Sink Water Heater

The Bosch Mini Tank Tronic 3000T under sink water heaters offer Point-of-Use hot water at a sink or shower.  If you’re looking to use an electric under sink hot water heater, this is a great model to look at. We recommend the 4 gallon for all your under sink needs.  The 7 gallon unit can be used for under the sink and shower needs combined.

The 4 Gallon Model is perfect for under a sink in the kitchen or bathroom, or can be used for short showers. It has a lightweight, compact design that’s easy to handle and install.  It can be wall-mounted and includes a 3 foot cord and standard 120-Volt wall plug.  The water connections for inlet and outlet are 1/2″ Male NPT.

The 7 Gallon Model can be used in a bathroom for a sink and shower or anywhere on demand hot water is needed. This hot water heater is designed to be hardwired. It’s a little larger than the 4 gallon model, so attention should be paid to how much room you have and the size of the unit.  The water connections for inlet and outlet are 3/4″ Male NPT.

Both models have some similarities and common functions.  More details about this under sink hot water heater are below:

  • Thick CFC-free foam insulation maximizes energy efficiency. Thermal efficiency is 98%.
  • Units can be wall / floor mounted (bracket included) with multi-directional mounting available (ES8 model only).
  • Temperature / pressure relief valve included.
  • Glass-lined tank for long service life.
  • 6 year limited warranty.
  • 6.8 Gallons per Minute recovery rate.
  • 150 PSI water pressure range.
  • 65 degrees – 145 degrees temperature range.
  • Draws 1440 watts/12 amps.  A 15 amp dedicated breaker or 20 amp shared breaker.
  • Installation Instructions

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Ecosmart ECO MINI 120V Electric Mini Tank Water Heater

The Ecosmart Eco Mini Water Heater is another electric Point-of-Use hot water heater providing heated water at a sink or shower.  Again, if you’re looking to hook up a small portable water heater to electric without requiring ventilation and recirculating lines and pumps, this is a great model to look at as well. There are 4 sizes total, we recommend either the ECO MINI 1 or ECO MINI 2.5 for under the sink, keeping up to 2.5 gallons of hot water ready.  While the 4 gallon or 6 gallon models are recommended for both an under the sink and shower water heater.

The 1 Gallon Model is perfect for under a sink in the kitchen or bathroom. It stores up to 1.5 Gallons of water to supply hot water.  Easy installation requires appliance line cord included plug. Plugs into standard 120V outlet.

All models have some similarities and common functions.  More details about this under the sink hot water heater are below:

  • 99.8-percent energy efficient
  • Easy installation requires appliance line cord included plug
  • Requires no venting, unit can be installed directly at the point-of-use
  • Adjustable temperature range of 50-140 degrees F
  • For booster and point-of-use applications
  • Plugs into standard 120V outlet.  Amperage Capacity is 12 Amps.
  • Pressure relief valve included

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Camplux Mini Tank Under Sink Electric Water Heater

The Camplux under sink water heater is another mini tank electric water heater.  There are 3 models available, for under the sink, we recommend the 2.5 gallon unit.  Like the other models listed above, the unit includes a glass-lined tank that offers great insulation and a plug that connects into a 120V electric supply socket. 

Some additional features we like for this unit specifically include the CSA listed temperature /pressure relief valve that is installed using the T/P valve into the threaded opening at the top of the water heater using heavy duty teflon tape.  The Camplux mini-tank water heater is equipped with an adjustable thermostat that once set will automatically control water temperature.  When the water heater is not being used for an extended period of time and there is a risk of freezing, either unplug and drain the water heater or turn the thermostat knob to the snowflake position to guard against freezing.

The Camplux Mini Tank Under Sink Water Heater is a nice unit with nice features.  More details about this under sink hot water heater are below:

  • Point-of-Use Mini-Tank Water Heater stores up to 2.5 Gallons of water to supply hot water under sink or basin where you need it.Perfect for a basement wet bar, patio kitchen station, garage, attic, or even in an RV or on a boat, hot water will quickly be in hand.
  • Save water by eliminating the wait for hot water to reach the faucet,reducing the heating losses.
  • Easy installation.Simply tap into the water line and install the heater directly at the sink. No need for costly recirculating lines and pumps.
  • The glass-lined tank offers great insulation and added durability, while the heater’s fast recovery rate eliminates long waits for hot water.
  • An external dial allows you to easily control the temperature range, and the CSA listed temperature-and-pressure relief valve enhances your safety.
  • A stylise and attractive exterior design that blends in seamlessly with existing decor when installed in a visible location, making this heater a great option in any room.
  • Water Heater measures: 14.5″ H x 11.75″ L x 10.38″ D;Weight: Approx.20 lbs.

Tankless Under Sink Water Heaters

Rheem Tankless Electric Under Sink Water Heater

We highly recommend buying a tankless water heater from a reliable company such as Rheem.  Tankless water heaters are much different than the mini tank under sink water heaters listed above. The installation requires direct wiring rather than a simple plug-in and lesser brand tankless water heaters have all kinds of warranty issues and quality issues.  Rheem makes quality products and offer 5 year warranties. Customer service is responsive.

We recommend the 13kw model from Rheem for your under the sink water heater.  Even though there are smaller models available, the extra capacity offers versatility if you want to add a shower or even washing machine to the output.  It is still a nice compact size, but we recommend the extra capacity at a price not much higher than the smaller models.

Performance Details from the Rheem website:

  • On demand, consistent and endless hot water
  • Compact and stylish with digital temperature control in increments of 1°F ranging from 80°F to 140°F*
  • 99.8% Energy efficient
  • Robust copper immersion heating elements with brass top increases durability and are threaded for easy replacement
  • Simple Installation
  • Digital temperature display
  • External controls to adjust temperature in increments of 1°F*

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Stiebel Eltron Tankless Electric Under Sink Water Heater

Another leader in tankless water heaters, Stiebel Eltron is another reputable company manufacturing leading tankless water heaters for all home needs. They have a number of sizes available, but we do recommend the DHC-E 12 Model.  It’s a great value that offers the ability to add more faucets, a shower and appliances if you wish to down the road.  At the price sold, there’s not much reason to buy a smaller unit with no freedom to add more hot water supply.

The top features we like for this model are that Stiebel Eltron electronically-controlled DHC-E models have their exclusive Electronic Temperature Control. Tankless electric water heaters from other manufacturers don’t maintain a steady temperature if the flow varies.  Electronic Temperature Control compensates for fluctuations in the flow rate and the incoming water temperature and maintains a constant water temperature output. DHC-E models have a flow sensor and two temperature sensors that feed their readings into the proprietary microprocessor control. Heating elements are engaged in stages, achieving the temperature you desire, with the lowest possible energy usage.

Specifications from the Stiebel Eltron website include:

  • Advanced microprocessor controls
  •  Best warranty in the industry
  •  Code compliance made easy
  •  No scalding
  •  Simple plumbing system design
  •  Sleek design fits in anywhere
  •  Seismic proof construction
  •  Proprietary technology
  •  Superior, reliable performance