Best Thermo Flow 2026

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Last Updated - 27.03.2026

Best Choice

01

Stiebel Eltron

STIEBEL ELTRON DHB 18/21/24 ST Trend Electronic Tankless Water Heater Made in Germany, Accurate Temperature Selection, Energy-Saving Thanks to 3i Technology, VDE Tested, 204202

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30% Off
9.7

Exceptional

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Safety: thanks to the air detection, the electronic pressure-resistant instantaneous water heater DHBSTTrend ensures high operational safety
Installation: with a dimension of 46.6 (H) x 22.5 (W) x 10.5 (D) cm, the electronic instantaneous water heater can be mounted.
Energy-saving: thanks to the energy-saving mode and energy efficiency class A, the instantaneous water heater allows efficient water heating with an annual power consumption of 481 kWh
CONNECTION: It is pressure-resistant and suitable for fixed connections - without plug - in addition, the selectable power 18/21/24 kW ensures more flexibility. In addition, horizontal mounting is possible.
Areas of application: thanks to the precise temperature setting, the instantaneous water heater is suitable for the kitchen, washbasin or bathroom.

279,99 € 399,99 €(30% Off off)
02

Bosch Thermotechnik

Bosch Tronic Line Electronically Controlled Instantaneous Water Heater 15/18/21 kW - Switchable, Pressure-Resistant, Continuous Temperature Selection, Modern Glass Look, White [Energy Class A]

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9.6

Exceptional

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Simply efficient: Particularly economical with energy class A. Up to 30% energy and water savings compared to hydraulic devices
Simple modern design: the device fits perfectly into any decor. High-quality materials and the new, optimised software of the water heater ensure a long service life.
For the installation of this device, a 400 V power connection is necessary, the assembly and the initial commissioning may only be carried out by a qualified electrician. Easy to install: quick over- or under-sink installation in 3 steps thanks to flexible cold water inlet hose and movable hot water spout as well as 3-in-1 power changeover
Easy to internet: By connecting to the WiFi gateway (optional), the device is internet-compatible. With the Bosch HomeCom Easy app, consumption data can be read, for example.
Easy to install: quick over- or under-sink installation in 3 steps thanks to flexible cold water inlet hose and movable hot water spout as well as 3-in-1 power changeover

256,85 €
03

Thermoflow

thermoflow Elex Electronic Tankless Water Heater

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9.5

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

The new generation of the Elex 21 N from Thermoflow ensures a tailor-made DHW supply as needed
For the installation of this device, a 400V power connection is required, installation and commissioning may only be carried out by an electrician.
Energy efficiency class A ensures low energy consumption
Convenient operation by setting the desired temperature up to 75 ° via symbols - incl. LED display.
Closed electronic instantaneous water heater for multiple control units - wash basin, shower and bathtub

199,00 €
Value for Money

04

AEG

AEG Electric Water Heaters with Small Storage Tank, white, 222162

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9.4

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Safe: tested safety by VDE testing institute, frost protection position
Please note: use only with low pressure/pressureless fittings, recognizable on the 3 connection hoses, do not use a hose shower fitting
Made in Germany
High hot water comfort for a water point: immediately hot water in the kitchen and bathroom
Economical and efficient: high-quality thermal insulation, low standby consumption, energy saving setting, energy efficiency class A
Easy temperature selection: stepless from 35-85°C, temperature selection limitation possible to 45/55/65°C
Easy installation: ready to plug, under-sink mounting

69,99 €
05

Thermoflow

Thermoflow Elex 5.5 kW Instantaneous Water Heater 230 V | Pressureless Small Instantaneous Water Heater | Hot Water up to 40 °C | G 3/8 Inch Connection | 3 L/min | For Washbasin or Kitchen Sinks

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9.1

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Water heater: The Elex 5.5 electric instantaneous water heater ensures pleasantly tempered water up to 40 °C and can be used as an under-sink device or as a instantaneous water heater for top table installations
Installation: The water heater has G 3/8 inch connections and is mounted on a wall. With dimensions of 18 (H) x 13 (W) x 6.8 (D) cm, the small instantaneous water heater is
Energy-saving: the 5.5 kW instantaneous water heater allows efficient water heating thanks to energy efficiency class A. The annual power consumption of the Thermoflow instantaneous water heater is 461 kWh
Box contents: the Thermoflow Elex 5.5 low-pressure instantaneous water heater is not ready to plug in and comes with instruction manual and mounting material. A low-pressure fitting is mandatory for commissioning
Areas of use: thanks to the power of 5.5 kW and a hot water output of 3 l/min. The electric water heater is suitable as an instantaneous water heater for the kitchen or washbasin

75,76 €
06

AEG

AEG Boiler BOI 5 U, Under-Sink Boiler 5 Litres Low Pressure with Plug 230 V for Kitchen Sink and Wax Basin, 2 kW, Made in Germany, 204616

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9.0

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Safety and quality: child lock thanks to adjustable temperature limit/scald protection; tested safety by VDE testing institute, frost protection, made in Germany
Installation: easy installation, with plug (socket and cold water connection sufficient), under-sink mounting
Energy-saving functions: high quality thermal insulation, low standby consumption, energy efficiency class A
Comfortable operation: selectable desired temperature, infinitely adjustable from 35 to 85 °C
Box contents: a AEG small storage, operating and installation instructions (English language not guaranteed), wall hanging
Areas of use: open boiler 5 l under-sink for a water point in the kitchen and bathroom; Warning: use only with low pressure/pressureless tap – recognizable on the 3 connection hoses – hose shower fitting is only to be used with kink protection

63,99 €
07

Thermoflow

respekta Klein-Durcherhitzer Thermoflow 3.5 inkl. Armatur

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8.8

Very Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Water heater: The Elex 3.5Arm electric instantaneous water heater ensures pleasantly tempered water up to 25 °C and can be used for top table mounting
Mixing tap: the two-handle mixer tap allows continuous temperature control. With the two separate handles, the hot and cold water flow can be individually adjusted
Installation: The water heater has G 3/8 inch connections and is mounted on a wall. With dimensions of 16.7 (H) x 13 (W) x 6.8 (D) cm, the small instantaneous water heater is space-saving
Box contents: the Elex 3.5 instantaneous water heater comes ready to plug in with mixer tap and instruction manual. A low-pressure fitting is mandatory for commissioning
Areas of use: thanks to the power of 3.5 kW and a hot water output of 2 l/min. The electric water heater is ideal as an instantaneous water heater for the kitchen or washbasin

99,00 €
08

Könighaus

Könighaus Infrared Heater - 1000 Watt - Eco Model - Energy-Saving Infrared Wall Heater - TÜV SÜD - Electric Heater with Overheating Protection - Includes Thermostat

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16% Off
8.7

Very Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

️Strong heating performance: Thanks to our many years of experience in the field of infrared, we can provide you with a high heat ratio. Watt / heating area: 130 W / 1–3 m², 300 W / 3–8 m², 450 W / 5–12 m², 600 W / 8–16 m², 800 W / 11–21 m², 1000 W / 14–26 m² and 1200 W / 18–29 m².
Slim shape: Our infrared heater has a simple and unobtrusive design thanks to the high-quality powder-coated aluminium frame.
Green heating: Infrared wall heaters provide a healthy heating solution. Thanks to the efficient direct heat, there is no air circulation and therefore no CO2 emissions. Our infrared electric heater is not only noiseless, but also ideal for house dust allergy sufferers and no dry air in rooms.
Durable: Könighaus infrared heaters are maintenance-free. With the Könighaus thermostat you have full control over your heating, for comfortable heating.
Box contents: Includes mounting material, thermostat and 1.80 m cable. This product is only suitable for well-insulated rooms or for occasional use. For optimal use, we recommend using a thermostat.

125,82 € 149,90 €(16% Off off)
09

Stiebel Eltron

Newest generation Stiebel Eltron boiler UFP 5 Trend with thermostop function, very compact, under-sink boiler 5 litres low pressure, with plug 230 V, 2 kW, made in Germany, 204966

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16% Off
8.5

Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Space-saving miracle: for more space under the kitchen sink
Safety: integrated anti-scald protection; 4-stage temperature limitation
Fitting + installation: low-pressure tap required – use of a pressure tap not allowed; only vertical under sink mounting; ready for plug: 230 V; easy wall mounting thanks to universal mounting strip; easy replacement of previous models
Energy-saving: the most compact of its kind with the lowest power consumption; the energy-saving thermostop function prevents unwanted heating of the fitting
Country approval: Germany, Austria, Poland
Comfort features: continuous temperature setting via high-quality rotary selector with tactile detent
Box contents: Stiebel Eltron small storage tank UFP 5 Trend, operating and installation instructions, wall hanging
Areas of use: pressureless boiler for the sink in the bathroom or the sink in the kitchen

83,99 € 99,40 €(16% Off off)
10

Stiebel Eltron

DNM Small Instant Water Heater

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15% Off
8.4

Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Main highlights

Temperature increase of the water by 25 degrees: the outlet temperature on the tap depends on the cold water inlet in the building; hot water flow rate: max; 2.0 l/min
Temperature increase by approx. 25 °C
Pressure-free operation
No standby or distribution losses
Installation: only horizontal over- or under-table wall mounting; earthing contact plug 230 V
Fitting: only for pressure-free fitting (recognizable by the 3 connection hoses)
Efficient: includes special aerator (included) for pleasantly soft water jet; saves water and energy without sacrificing comfort
Country approval: Germany, Austria
Box contents: Stiebel Eltron instantaneous water heater DNM 3, special aerator, sieve, operating and installation instructions (English language not guaranteed)
Areas of use: mini instantaneous water heater with plug for hand washbasin in the guest toilet; immediately lukewarm water (approx. 35°C); not suitable for kitchen and bathroom - here a Stiebel Eltron small storage tank or instantaneous water heater from 11 kW is necessary

87,99 € 104,05 €(15% Off off)