Point-of-Use Water Heaters - POU Buying Guide and Top Models

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In recent years, the demand for water heaters across the U.S. and Canada has gained a lot of traction. Point-of-use electric water heaters  (POU) seem to be the solution for many due to their inherent benefits. They instantly heat water and, with a convenient location, shorten water delivery time, helping you save time, energy, water, and money while increasing the comfort level and overall satisfaction.

If you take a closer look at the POU electric water heaters market, you would be greeted with several brands and models that can even throw you into a state of confusion. We understand the challenges buyers pass through when looking to purchase the best water heating system for their homes and offices. And that is why we created this post to help you make an informed buying decision.

But before we dive deeper, let's take a look at what POU electric water heaters are, their features, advantages, and disadvantages, and compare the different types on the market.

Highlights

What are point-of-use water heaters?

POU water heater

Point-of-use electric water heaters are small and portable devices designed to produce hot water instantly, in a situation where there is limited space, and hot water is needed at the point of use. They are designed as tankless or tank-type, utilizing gas or electricity. Due to their small size and heating elements/burners, they cannot supply hot water to an entire building. You will need one large and powerful heater, either tankless or tank-type, and POU heaters for distant sinks or where you need water delivered fast.

They are referred to as "under-sink water heaters," also "under counter" because they are often installed under the bathroom, counter, or kitchen sink – right where they are needed. They can be added to an existing system or used independently as a single unit.

POU water heaters are designed to serve low-volume fixtures like lavatory sinks in garages, cottages, small apartments, as well as mobile and residential homes.

How does the point-of-use water heater work? 

Here is how the POU system works:

POU heaters with storage tanks are similar to conventional tank-type heaters but are much simpler, smaller, and usually have a smaller gas burner or one heating element. Water is stored inside the small storage tank, where it is heated to the set temperature. Then, once you open the tap, hot water starts flowing.

Tankless models operate in the same manner as the big brothers; they bring in the cold water through the inlet tube into the heat exchanger. In the electric models, one heating element heats the water to the temperature set on the thermostat. Hot water moves through the outlet for domestic or office use. The unit comprises a thermostat, heating elements, fuse, control buttons, wire connections, safety cut out, and cold and hot water connections.

Homeowners have options to buy electric POU water heaters that operate on voltages from 110V to 277V and can be either hardwired or simply plugged in.

In addition to electric models, gas tankless units use the gas valve, combustion chamber, heat exchanger, flue vent, electronic ignition, and electronic board. Water is heated while it is passing through the heat exchanger - on demand. Also, as opposed to tank-type heaters, tankless deliver hot water in an endless supply, continuously.

Sizing tips for POU water heaters

Use this article to find more info about sizing both tank-type and tankless water heaters.

The table below shows how much hot water in gallons per minute is needed for a particular application.

  • Bathroom 0.5-1.5 GPM
  • Kitchen 1.5 GPM
  • Shower 1-2 GPM
  • Dishwasher 1.5 GPM
  • Clothes washer 2 GPM
  • Tub 4 GPM

This table shows how much hot water in gallons is needed for different family sizes:

Family size (# of people) 

Peak demand (gallons) regular/high demand

2

3

4

5

6

7

45-55

55-65

65-75

75-85

85-100

100 or more

When to consider POU water heaters

  • Distant sinks and remote bathrooms (when it takes hot water too long to reach the tap from the central heater)
  • New home construction (if the higher efficiency cannot be achieved with any of the systems)
  • Old homes (if there is an increased demand for hot water)
  • Demanding applications, such as the hot tubs (only if electricity is used for heating)
  • Where a small amount of hot water is needed (handwashing, cleaning dishes, brewing a coffee or tea)
  • To supplement an existing tankless or tank-type heater (electric, gas, solar)

Advantages of using POU electric water heaters

The following are the benefits of installing a POU electric water heater in your homes:

Reduces wait time: If you install a POU electric water heater in your home and at the source, it will help you reduce the wait time associated with a central heating system and long pipes.

Saves money on gas and electricity: The money you would have expended on gas and electricity would be saved simply by installing a POU electric water heater in your kitchen or bathroom. Plus, POU units can help you save on water consumption.

This system can be used where retrofitting is impracticable or too expensive.

Steady hot water flows: In large buildings, multiple POU electric water heaters can be installed in different locations to guarantee a steady supply of hot water instead of running pipes as with a central heating system.

Small POU heaters can be used in conjunction with storage tank-type heaters to reduce or eliminate the stand-by heat loss, even tankless, to minimize temperature fluctuation or the "cold water sandwich" effect.

Temperature control: One of the greatest benefits of using this system is the ability to regulate water temperature on the spot.

Tankless models can deliver hot water in endless supply and on-demand.

Environment friendly: POU tankless water heaters heat water where and when it is needed, reducing the carbon footprint. No more wasting energy between the tank heater and the tap.

Disadvantages

  • Point-of-use electric water heaters are not that great for high hot water volume.
  • The initial cost of installing multiple POU electric water heaters in your building is greater than a centralized heating system.
  • POU units cannot meet the demand for hot water if it is to be used as a backup for geothermal heat pumps and solar heating systems.

Features of POU units

Most of the POU electric water heaters you will find on the market are equipped with advanced components to increase their efficiency and performance, control the system automatically, and even saves on energy. They are also equipped with a heating element that transfers heat to the surrounding cold water. 

Some POU units come with tanks insulated with glass or ceramic to handle the corrosive effect of hot water. Plus, they are fully automated by incorporating a surface-mounted thermostat, which helps regulate the hot water temperature. They are durable, portable, and supplied with an electrical cord to plug into a standard electrical outlet.

Comparing different types

Many homeowners are also asking what the difference between POU and tankless or between POU and tank-type is.

To make it easier to understand, POU water heaters are designed as tankless and tank-type. POU tankless models are intended to heat cold water passing through the heat exchanger and deliver hot water to one fixture - a low water flow system. The tankless type is rated based on the volume of water they can handle per minute. Popular sizes have a water flow of 2, 4, and 6 gallons per minute (GPM). An excellent example of the tankless-type is Tempra from Stiebel Eltron.

POU tank-type heaters utilize insulated mini tanks with capacities from 2 to 30 gallons where the largest models can be used for one-person shower, while the smallest ones, which we often see in kitchens, are for a small number of dishes, hand washing, shaving, and such. An excellent example of a mini tank-type POU unit is Ariston from Bosch.

POU vs. the whole house water heating

In simple words…

Point-of-use water heaters (POU) are designed to deliver a small amount of hot water to a single fixture and mainly for small jobs.

Whole-house water heaters have higher water flows or larger tanks, distributing plenty of hot water even to multiple applications.

Review of the best-selling POU electric water heaters

Bosch electric mini-tank water heater - Tronic 3000 T

If you need a POU electric water heater that delivers instant hot water on-demand and fast, then the Bosch electric mini-tank water heater from the Tronic series is a force to reckon with. It is one of the best-selling POU electric water heaters you will find on the market.

Tronic 3000 T is designed to supply a constant hot water volume for distant fixtures in your bathrooms, kitchens, and offices. It supports one sink; plus, it is easy to operate. All you need is to plug it into a standard 12V electrical outlet once hung on the wall or mounted on the floor.

Once operated, it will immediately transfer hot water for your use; instead of waiting for hot water, as with a central heating system. The model is equipped with one 1440 W heating element that can achieve the maximum temperature of 145 F. It is automated, meaning the thermostat will help you control the water temperature for your comfort. What's more? It can produce hot water up to 98% efficiency. You won't go wrong if you purchase and install this model in your house.

EcoSmart ECO 11

Another top-selling POU electric water heater you should give serious consideration is the EcoSmart ECO11 electric water heater. This model is small, compact, and guarantees an endless supply of hot water. Our research discovered that the EcoSmart Eco11 electric water heater could help you save up to 60% on your water heating cost and water consumption.

It is designed with a digital temperature control unit; thus, helping to keep the water temperature in check. The hot water temperature can be regulated between 80 and 140 F using the digital control unit. The casing is made of stainless steel and copper components. Plus, it can deliver hot water at 99.8% efficiency.  Due to its tankless nature, it can be installed above the sink, under the sink, on the wall, in the bathroom, kitchen, office, basement, RV, and garages.

Still, on this model, the minimum water flow is 0.25 GPM, meaning that the only above that value will operate. It is easy to maintain, and corrosion does not arise since it is made with copper.

Stiebel Eltron Tempra

Do you need a constant supply of hot water in your bathroom and kitchen? Then put the Stiebel Eltron Tempra POU electric water heater on your shopping list when next you hit the market. The manufacturers are reputable when it comes to producing high-quality and reliable heating systems. This model is designed with a heating element, a temperature controller, and a corrosion-resistant casing. The temperature controller will help you adjust the hot water temperature for domestic use.

It can be installed in your bathrooms, kitchen, or offices where the central heating system is not practicable. It can produce hot water with up to 99% efficiency. With the Stiebel Eltron Tempra POU electric water heater, your spending on electricity will drastically reduce. You won't go wrong with this model because it is easy to install, maintain, and operate.

So is it worth it to buy a point-of-use water heater?

Point-of-use electric water heaters are mini and portable affordable devices that guarantee fast hot water delivery at the point of service either in homes or offices. Once you purchase any of the three models above, hot water would be delivered promptly; thus, resulting in water, time, and space savings.

POU heaters are your cost-effective solution for heating water because they are cheaper to operate, do not waste too much energy, allow precise and on spot temperature adjustments, deliver hot water only when need it, and are less expensive than whole-house water heaters.

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