10 Best Water Heaters: Reviews and Buying Guide (2018)

They heat the water reliably and some even to the degree. They ensure that you can enjoy a warm shower at any time and thoroughly rinse dishes after a delicious meal. Even in a small guest toilet, warm water in the hand sink is available for your visit. A water heater is a cost-effective and energy-efficient solution for many households.

But which electric instantaneous water heater is the best? On gametoaid.org you will receive the latest information on the subject “hot water preparation and instantaneous water heater”. We will briefly introduce you to the bestsellers, explain the operation of these devices and the differences between the different versions. 

10 Best Water Heaters

What is a water heater?

An important note in advance: This product comparison and purchase guide deal exclusively with electric instantaneous water heaters. A water heater is an electrical appliance that converts the electromagnetic energy into the thermal and thus heats the water. This water heater taps the cold water, heats it to a temperature set by the consumer and forwards the water to the compatible fitting. A water heater does not store hot water but heats the water that passes through a pipe system installed in its housing.

What are the typical applications of a water heater?

A water heater is needed wherever there is no water heater in the household or its capacity is insufficient. These devices are most commonly used in the following four areas:

  • Hot water supply for the entire household: If the heating system does not have a boiler – as is the case with some space-saving combi steamers – it often needs the support of a water heater. In this way, the situation can be avoided if the hot water only for one tapping point and at the same time using a shower and kitchen sink threatens a convinced warm shower a cold shock. A powerful instantaneous water heater with a power consumption of 18 kWh, which is designed for the simultaneous supply of several taps, prepares hot water for the entire household.
  • Water heating for individual taps: It happens that not all taps in the household are equipped with a hot water connection. A smaller hot water tank or instantaneous water heater, which is designed only for the supply of a consumer – for example, a hand sink in the guest bathroom – offers here as a practical solution.
  • Holiday home, garden shed: The third application area of the water heaters is holiday homes, which have a cold water connection. Here, water heaters are also gladly used and deliver hot water to several taps. However, it is important to remember that most models require a power connection!
  • Camping, RV: Some instantaneous water heaters are designed for mobile use and can be connected to a gas cylinder with propane gas as a source of energy and in most cases have a shower head.

How is a water heater constructed and how does this water heater work?

The principle of a water heater remains largely the same regardless of the actual design: the water is tapped on a cold water connection and flows into the interior of the device. There, the cold water has a compactly built pipe system to pass, with a water regulator takes over the task of keeping the water pressure constant. In this way, the water can heat evenly, so there are no unpleasant or even dangerous temperature fluctuations. The water flows around the heating elements, for example, the conventional heating coil, which warms it up to the desired temperature. Then the water runs out of the fitting, which, depending on the model, either mixes it with cold water or delivers it directly to the consumer.

Which models of water heaters and water heaters are there?

Our comparison portal on gametoaid.org informs you in this section not only about the pure water heater but also about some related models.

Hydraulic water heater – the classic

These conventional water heaters use the classic hydraulic technology, with the help of a Venturi nozzle, the water pressure is compensated. Today, the water is heated using efficient bare-wire heating elements.

Today’s hydraulic water heaters, however, allow an adjustment of the water temperature by switching between two or three power levels. In general, these water heaters are considered to be less energy efficient than the electronically controlled models, as the exact temperature adjustment is not feasible and the appliances overall heat the water above average.

Electronic instantaneous water heaters – the modern version

With these water heaters, the water temperature is controlled by electronic sensors, distinguishing between the models with two and three sensors. The former monitor the inlet temperature and temperature inside the unit. The triple sensor systems also control the outlet temperature and flow rate. The latter models are often called fully electronic instantaneous water heater designated. The electronic or fully electronic instantaneous water heaters make it possible to adjust the temperature to the exact degree because if more water is tapped than the heater can heat up to the set temperature, the flow is somewhat throttled. The temperature remains stable. Precise temperature control not only provides more comfort and safety but also saves energy.

Hot water tank – designed only for small amounts of water

The small storage tanks are mini-sized and always have a certain amount of hot water ready. For home use models are available with a 5 l, 10 l or 15 l water tank. Understandably, energy is needed to keep the hot water available, so that the small storage tanks are on average less energy-efficient than the classic instantaneous water heaters. It depends on the thermal insulation, how efficient one or the other model actually is.

When the hot water from the water tank is used up, cold water flows into the tank and is reheated. However, this can lead to the interruption of the hot water supply, since the device requires a while to warm the water to the required temperature.

Mobile water heater – can be used anywhere

Most mobile models use natural gas from a gas cylinder to warm up the water and connect to the garden hose. The portable water heaters are usually not very powerful and can heat the water to about 40 ° C. Not a few models are already equipped with a shower and ideal as mobile showers.

Unpressurized, open water heaters – to be used only with appropriate fittings

In a non-pressurized or low-pressure instantaneous water heater, the water barrier is installed between the water connection and the unit. Thus, the water flows into the water heater only when the tap is activated. Only then the so-called dynamic pressure is built up and at the same time, the water is heated. The outlet of a non-pressurized heater is always open. The non-pressurized heaters are relatively inexpensive but can be operated exclusively with an open, pressure-free valve. The water treatment takes a little longer in a pressureless water heater because the water must first get into the device to be heated.

Pressure-resistant instantaneous water heaters – particularly versatile

In a pressure-resistant water heater – and most modern devices are designed as a flameproof version – there is always water in the pipe to be heated. Thus, the water heater is always under pressure, which is its relatively complex construction and therefore a higher purchase price to explain.

With which features and functions is a water heater equipped?

Our purchase guide and comparison portal on gametoaid.org lists for you the most important features of a continuous flow heater and explains which are particularly relevant for the consumer.

  • Temperature Controllers or Circuit Breakers: Most mid-range and upper-class models have a temperature controller or offer the option of switching between two or three power levels (for example, for the washbasin and bathroom on the one hand, and the kitchen washbasin on the other). The fully electronic upper-class devices allow a degree-precise adjustment. Control is most often done with a handy rotary control.
  • Two or three temperature sensors: Often referred to as 2i and 3i technology, the electronic sensors monitor the water temperature. A triple control system ensures an even more precise adjustment of the temperature, as among other things the outlet temperature is permanently measured.
  • LCD display: A backlit display is included in the upper middle class and upper-class models. The display shows current values, including, for example, the water temperature, the time of day, and the energy consumption. In addition, the necessary settings can be made using the handy buttons.
  • Parental control: The so-called parental control is a useful feature, especially for high-performance instantaneous water heaters. If the fuse is activated, the device does not heat the water above 43 ° C, thus preventing the risk of scalding.
  • Automatic venting or air bubble detection: If air is collected in the water pipes, the efficiency of a water heater drops and the water is no longer heated to the desired temperature. While manual venting was still required on older models, modern water heaters are no longer the case: the sensitive sensors detect the air bubbles and cause automatic venting.
  • Pre-installed programs and options for individualization: The high-flow water heaters allow the user to personalize the device, including pre-installed programs for showering, as well as the option of storing your own well-being temperatures and making the evening bath a feel-good experience. For example, a wellness program allows a change between hot and cold showers or, if desired, a refreshing cold finish to the morning shower.
  • Eco mode. In this mode, targeted water and energy savings are achieved by limiting the maximum flow rate to 8 – 10 liters.
  • Remote Control. This feature exclusively distinguishes particularly high-quality devices and increases the ease of use. A remote control is especially useful if a water heater serves several taps: If the dishes in the kitchen different settings than previously used when showering, they can be made conveniently via remote control, without touching the device installed in the bathroom:

Is a purchase of instantaneous water heaters promoted by the state?

Yes, a switch from a hydraulic to a fully electronic water heater is worthwhile, despite higher acquisition costs. The Federal Ministry of Research and Technology is sponsoring a project of the Gesellschaft für Energiedienstleistungen GmbH & Co. KG (GED), in which a purchase of an electronic instantaneous water heater is rewarded with 100, – EUR. It is sufficient to submit some documents such as the proof of purchase and the craftsman’s bill in order to secure the premium.

Buying guide – in five steps to the right water heater

Use our guide on STERN.com to find the model that best suits your needs. Answer the following five questions for yourself to progress five steps on the way to the Wish-Through Water heater.

  1. Do you attach great importance to maximize energy efficiency and environmental friendliness? Then it should be a fully electronic instantaneous water heater. By the way, it does not have to be the most expensive model, because on average every electronic water heater saves about 20% of the electricity costs compared to a conventional, hydraulic instantaneous water heater. Also, make sure that your device has an ECO function.
  2. Would you like to save your wallet? In the long run, the electronic water heater proves to be an economical variant. But the acquisition costs are often in the mid-three-digit range. The hydraulic water heaters are cheaper, especially when it comes to compact models.
  3. How many taps are to be supplied? It is by no means worthwhile to get a high-class instantaneous water heater for a hand sink in the guest WC. A compact model, even without a knob, does it too: Provides a pleasantly warm water. A high-performance instantaneous water heater, on the other hand, has no problem supplying your entire household with water that has been heated to the exact degree.
  4. Do you love the comfort and are you willing to pay a little more for it? Then you certainly benefit from such features as “wellness”, remote control or individual programs.
  5. Would you like to use the hot water as soon as possible? In this case, a powerful water heater from 21 kWh helps. The higher the power, the safer the hot water supply is, especially if several taps are to be operated. The investment costs also increase with the performance.

Is there a water heater test of the Stiftung Warentest?

The tests of Stiftung Warentest are considered independent and objective and enjoy a perfect reputation among consumers. Tens of thousands of products and services from all market segments have been closely examined and put to the test. In 2015, the instantaneous water heater was also on the agenda: The experts selected 11 models, including exclusively electronic and fully electronic water heaters. A hydraulic instantaneous water heater was just for comparison. The models of Vaillant and Stiebel Eltron were among the water heater test winners, but not a single device could convince the strict tester completely.

However, the relatively poor ratings are by no means related to the functionality, processing or equipment of the devices, but only with the overall negative from the view of the testers balance of electricity as an energy source. The experts find gas or solar energy more environmentally friendly, which makes them only partially right from today’s point of view. If the energy transition continues to progress successfully and the share of clean energy in our electricity mix continues to increase, the water heaters would definitely turn out to be environmentally friendly electrical appliances.

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