The Ultimate Guide to Tankless Water Heaters
Home owners are often in two minds when it
comes to the type of water heaters they should install in their homes. On the
one side, we have traditional tank water heaters. They’re bulky in size and they’re
less ecologically friendly than tankless heaters.
On the other side, tankless water heaters are
becoming more popular as their price is dropping. They’re more convenient for
installation and maintenance, plus, they consume less electric energy. In this
ultimate guide to tankless water heaters, we’re going to discuss the main
differences between tank and tankless heaters, as well as the key advantages of
After that, we’ll provide the reviews of
five top-notch tankless heaters.
Tank vs. tankless water heaters
In a tank water heater, water is kept in
the tank, where it’s heated when the heater is switched on. However, when you turn
the heater off, the water inside the heater gets cold after some time. As a
result, you might waste electric energy to heat the same amount of water for
Even if you keep the heater on all the
time, as you consume the hot water from that tank, the water storage is being
filled with cold water, which also has to be heated.
As such, tank water heaters are ecologically
inefficient, especially when we apply the current efficiency
standards for water heaters.
Tankless heaters, on the other hand, are
made to avoid that standby energy loss, so typical for tank heaters.
In a tankless water heater, water is heated
as it flows through the coil inside the unit.
This technology makes it possible for users
to use hot water whenever they need it. They don’t have to wait for cold water
to get hot in a tank, but it’s heated as it flows through the heater.
The downside of some tankless heaters is the
limited amount of hot water that can be delivered per unit of time.
On average, these water heaters can provide
2-5 GPM (gallons per minute) of hot running water. This can be problematic for larger
families or bigger households, since they might lack hot water when they’re
simultaneously using several showers and household devices that need hot water.
That’s why some people decide to install two
or more tankless heaters and have them joined together,
to increase their output of hot water.
Some other people decide to install a
heater per appliance that needs hot water and that way ensure steady water flow
and temperature for all their needs.
Finally, you can go for a larger tankless
water heater to cover all your needs, but it’s recommended to always consult a
professional who will tell you whether or not one tankless heater can meet all
your demands for hot water.
Electric and gas tankless water heaters
There are two major types of tankless water
heaters: electric heaters and gas heaters.
Electric tankless heaters use the electric
power to heat cold water. Since electricity is more affordable than gas in many
parts of the world, electric tankless heaters are still more popular than their
An electric tankless water heater is
plugged into the grid and uses the electric power to heat the water running
through it. Some modern heaters of this kind come with cutting-edge
technologies that optimize both the electricity and water consumption. You can
read about some of them later in the text.
Gas heaters, on the other hand, require a
source of natural gas in order to work. You can get this problem solved in two
different ways. On the one hand, you can connect your gas tankless heater to
the local gas network.
On the other, you can get a portable tank
of gas and use it as the gas source for your heater. This option will work for campers,
tourists and people who often go to their holiday houses.
Also, gas heaters burn gas to heat water,
which is why you need to vent
the gas heater, in order to remove make the air in the heated place safe.
For all these reasons, most households opt
for electric heaters.
The most prominent tankless water heaters
Rheem RTE 13 Electric Tankless Water Heater, 4 GPM
The first tankless water heater we’re going
to present in this comprehensive guide is the Rheem
RTE 13 Electric Tankless Water Heater.
The high-quality heat exchanger made of
copper and brass comes with a 10-year warranty, which guarantees first-class heating
performances and durability.
Since we’re living in the time of
ecological awareness, it’s important to stress out that this heating device has
Star label. This means that it’s categorized as a highly efficient water
Two most common concerns regarding tankless
water heaters are the energy efficiency and the speed of hot water delivery. As
for the first consideration, the modulating heat exchanger makes this heater an
ecologically friendly device. Also, no heat is lost in the standby mode and it
emits no greenhouse gases.
You can easily set the temperature on the
device itself, while the LEDs on the unit show whether the heater is active or
in the standby mode.
When it comes to technical specs, here’s
what this Rheem heater has to offer.
The wattage of the Rheem RTE 13 is 13kW and
the voltage is 240 V. As for the water supply features, it delivers 4 gallons
of water per minute (4 GPM).
What makes this heater a great point-of-use
choice is its compact shape and size. Namely, its dimensions are 7.2 x 7.2 x
7.2 inches. When you know that it weighs 7.35 pounds, it becomes even more
obvious why the Rheem RTE 13 can easily fit into many different spaces.
The Rheem RTE 13 is a great option for
homes and bathrooms where it can be installed close to the shower unit and the
bath. If you think in an economical way, you can reduce its heat to 60% or 70%
of its full heat amplitude. That way, you’ll always have enough hot water for your
needs and you’ll save some electricity along the way.
When compared to a tank water heater,
you’ll pay a similar amount of money for the traditional heater and the Rheem
RTE 13. Still, for an average water consumer, the latter will pay off in the
first year and a half. After that, you can enjoy the ecological and convenient
benefit of this tankless electric water heater.
As for the cons of this heater, some users
have reported that it sometimes won’t turn on in case of lower water pressure. In
addition to that, sometimes the hot water flow isn’t consistent, which might result
in unexpected jerks of hot water from time to time.
EcoSmart ECO 11 Electric Tankless
The next tankless water heater we’re going
to analyze here is the EcoSmart
ECO 11 electric heater.
Due to the self-modulating
technology, originally patented by EcoSmart. In a
nutshell, this tankless water heater and many other similar products made by
EcoSmart control the energy and water consumption through the Flow Sensor
technology. By modulating the current need for hot water, rather than switching
the heater on and off, this technology represents a great blend of user
friendliness and energy efficiency.
The EcoSmart ECO
11 comes with the WaterSense label, which means that it’s made to save water while providing
you with enough hot water all the time.
of this heater is the option to adjust the temperature of the water degree by
degree using the digital control on the heating unit.
As for the warranty,
you get a lifetime warranty on the heat exchanger, the elements and the
electronic parts. Still, it doesn’t recover the replacement procedure.
The EcoSmart ECO
11 perfectly works with one shower attached to it in colder environments, while
in warmer climates you can connect two shower heads to a single EcoSmart unit.
Similar to the
aforementioned Rheem RTE 13, the EcoSmart ECO 11 also comes with the 13kW
wattage and 240 V voltage.
The dimensions of
this device are 6.5 x 13.5 x 10 inches, with the weight of 6.5 pounds. As such,
it’s a perfect choice for point-of-use settings, as well as for places with a
low water flow.
The most specific
disadvantage, or rather demand for this water heater is the electric service it
requires. Namely, you’ll need 120 amps of electric service only for the
EcoSmart ECO 11 if you want it to work properly. Because of that, contact a
professional electrician before you buy this heater and check if it’s
compatible with your wiring.
Stiebel Eltron Tempra Plus 24 kW
with Self-Modulating Power Technology & Advanced Flow Control
Some homeowners can’t satisfy all their
water-heating needs with smaller tankless heaters. If you’re one of them, Stiebel Eltron Tempra Plus 24 kW could be a great choice. The
Tempra series is a well-known line of water heaters, which has been updated and
improved in many sections.
For instance, the
Stiebel Eltron Tempra Plus 24 kW model comes with the highly Advanced Flow
Control technology. In simple terms, this feature
eliminates the so called “cold water surprise”. If the demand for hot
water is larger than the Tempra Plus can provide at the moment, Advanced Flow
Control will reduce the water jet, but there won’t be any change in the temperature
of the running water. Also, you can simply adjust the temperature of hot water with
the user-friendly dial on the unit.
parts have also been improved, which makes them perfectly compatible with the
present-day ecological standards.
Compared with modern
tank water heaters, the Stiebel Eltron Tempra Plus 24 can reduce your
electricity bill up to 20% and the manufacturer claims 99% energy efficiency
with this tankless heater.
When comparing it
with traditional tank heaters, this model leaves a lot of free space, which
makes it perfect for wide range of real estates, from apartments and houses to
advantage of Stiebel Eltron Tempra Plus 24 over gas tankless water heaters is
its affordability. Apart from that, its installation is much simpler than
installing gas tankless heaters, mostly because you don’t have to bother with venting.
Finally, here are
some key technical specs. The wattage of this tankless water heater is 24kW and
the voltage is 240 V. The electric
service of the place in which you’ll be using the Tempra Plus 24 should support
the minimum amperage of 2×50.
The dimensions of
this water heater are 21.5 x 19.5 x 8.8 inches and the weight is 16.1 pounds.
Eccotemp L10 Portable Outdoor Tankless
If you have a large backyard or a holiday
house outside the town, you can make great use of an outdoor tankless water
heater. One of the most prominent representatives of this group of portable
heaters is the Eccotemp
L10 gas tankless water heater.
The major concern with portable heaters is
the functionality of batteries and the connectivity of the gas input. For this
model, you need to use 2 D-cell batteries, which start the ignition of the
heating system. As for the gas input, it has an integrated compression fitting.
The only thing you need to do is connect a tank of liquid propane with the
What you should also take care of when it comes
to outdoor water heaters is the type of the water supply system. In case there’s
no water supply network in the area where you install this heater, you can
relax. The Eccotemp L10 is compatible with a 12-V water pump.
When it comes to water flow, this tankless
water heater can provide you with the maximum of 2.6 GPM. These features will
be sufficient for two devices using hot water to work simultaneously.
Since the Eccotemp L10 hasn’t been tested
at the altitudes higher than 5500 feet, it’s recommended not to use it in
The dimensions of this heater are 8 x 14 x 25.5
inches and the weight is 27 pounds. As such, it can fit into any average trunk
and be taken wherever you go on holidays or excursions.
The most adequate surroundings for this gas
tankless water heater are holiday cottages, ranches, camps and other outside areas.
Additionally, you can even attach
the Eccotemp L10 to your trailer, next to the rainwater tank, so as to make
it even more ecologically efficient.
On the negative side, it might provide a
little bit low output of hot water in areas with lower groundwater temperature.
That’s why you should get the info about the groundwater temperature in your
area and talk with the manufacturer before you decide to buy this practical
EcoSmart ECO 27 Electric Tankless
Water Heater, 27 KW at 240 Volts
Another handy tankless water heater from
the EcoSmart family, the EcoSmart
ECO 27 device is a cutting-edge heating unit.
This model comes with the aforementioned
Self-Modulating Technology, which enables the optimum consumption of water with
the economical use of electric energy.
What puts this water heater ahead of the
curve is the heating quality to provide 3 GPM at the minimum temperature of 37°
F (2°C). As such, the EcoSmart ECO 27 is a perfect choice for people living in
the colder parts of the world. It can provide enough hot water for two showers
working at the same time in those weather conditions.
When used in warmer climates, the ECO 27 can heat enough
water for several devices working simultaneously. In such conditions, this
heater will provide you with hot water at the 6 GPM rate. All these features
will meet the demands of most families that live in houses and this audience
should go for this heater.
The sleek design of this EcoSmart device and the digital dial
for temperature make this unit a visually appealing water heater, a well.
As for the electrical specifications of the ECO 27 water
heater, its wattage is 27 kW – hence the number in its name – and the voltage
is 240 V. Since it has the WaterSense technology, this heater will provide you
with the required amount of hot water without wasting any additional water.
The dimensions are 3.6 x 17 x 17 inches, so it’s the largest
heater of all the units reviewed in this article.
Obviously, the owners of smaller houses and apartments might
find it too big for their needs.
Also, since the electrical requirements for installing this
heater are three 40 amp double
pole breakers, some home owners will find it too demanding.
Still, for large families that live in houses with potent
electric service, the ECO 27 heater is a perfect choice.
In this day and age, energy efficiency is
extremely important in terms of any electric device. When we draw the line
below all the tankless water heaters presented in this text, one candidate gets
ahead of the curve – the Stiebel Eltron Tempra Plus 24
kW. Its auto-modulation features save energy while generating enough hot water
at every single moment, which Stiebel patented as Advanced Flow Control. We’ve
already highlighted in the review of this heater that its energy efficiency
rate reaches 99%.
Also, the heating chambers made of copper guarantee durability and high
performance of the Tempra Plus 24 kW.
On the other side, it’s important to mention
the Eccotemp L10 gas tankless heater, as the only unit
from the gas specter of tankless water heaters in this review. Its size and
dimensions make it a practical heater that can be easily installed on houses,
cottages and trailers. Also, due to its simple installation, you can easily
attach it to a plumbing system and connect a portable propane tank to it.
Now that you’ve
read our reviews and seen our verdict, you can get the tankless water heater
that will suit your needs. That way, you’ll start saving money and energy while
enjoying the seamless flow of hot water in your household.