Comparison Electrolux EWH 100 Centurio IQ 2.0 vs Thermex Combi ER 080 V

— Gas. In such a device, it is easy to provide a high heating power — even in the most modest devices, it is calculated in kilowatts. However, gas models are difficult to install, since they require a gas line and a flue gasket to remove combustion products. At the same time, the mentioned high power is relevant mainly for gas water heaters (instant water heaters), and most gas models belong to this type. However, there are also storage gas water heaters.

— Mains. Electric water heaters are versatile and easy to install — unlike gas, and they do not need a flue. On the other hand, even for relatively low-power models (up to 5 kW), high-quality electrical wiring is needed, and more powerful heaters require a separate connection to the electrical switchboard or even a three-phase power supply. In addition, electric heaters are often considered more expensive to operate than gas heaters. This option is popular mainly among storage models (see "Type").

— Indirect. Such water heaters do not have their own heating element (electric or gas). Its role is played by a heat exchanger, through which a coolant moves, heated by an external source (most often a heating boiler) — due to this, the water is heated. Indirect heaters are made only for storage (see "Type") — t...his is due to the design features. They cannot be installed autonomously — an external heating source is required; the installation process itself can be quite complicated. The main advantage of this option is that it does not require a separate supply of electricity or gas to heat water. In addition, an indirect heater allows more efficient use of heat from a boiler or other heater.

— Combined. Such water heaters are a kind of hybrid between indirect and electric. The main heating of the water in them is provided by a heat exchanger operating at the expense of an external source of heating (for example, a heating boiler) or a built-in heat pump. An electric heating element (usually, a heating element — see "Heater type") serves for additional heating. Combined heaters provide a higher temperature than conventional indirect heaters and are more economical than electric ones. Their main disadvantage is their rather high cost.

The regular way to install a water heater.

The choice for this parameter depends primarily on how much free space is available for installing the device and what shape this space has. Therefore, when there is a lot of space (for example, the user has an entire wall in the boiler room of a private house at his disposal), this parameter can be ignored. But in cramped conditions, each installation method will have its nuances.

— Vertical. Vertical arrangement devices, elongated in height. This option is well suited for narrow cramped spaces — for example, a bathroom in a small city apartment.

— Horizontal. The horizontal layout is less suitable for tight spaces than the vertical one but in some conditions, it may be optimal — for example, if the place under the device looks like a low horizontal niche. Also, note that many instant water heaters are produced in this design (see "Type") — they do not take up much space, and horizontal orientation is considered optimal for such devices for several reasons.

— Floor. Floorstanding models (as opposed to all of the wall mount options described above). The main advantage of such an installation is simplicity: there is no need to drill walls and prepare other special fasteners; it is enough to have free space on the floor. In addition, weight restrictions are not so critical for floor water h...eaters, and this method can be used even for the most powerful, capacious and, accordingly, large models. On the other hand, free space on the floor is not always available, and this installation method is not suitable for cramped conditions.

— Universal (wall mounted). Devices that can be placed in any position — both horizontal and vertical (see above for details). The advantage of this option is obvious: the user can choose the installation method of his choice, depending on the situation.

The volume of the tank installed in the storage water heater (see "Type"). It is one of the key parameters for such devices. On the one hand, a large tank allows you to keep a large supply of water and reduces the risk that it will run out at the most inopportune moment; this is especially important when water consumption is high, such as in a large family. On the other hand, a volumetric tank correspondingly increases the size, weight and cost of the entire device, requires reliable fastenings (when installed on a wall), and more energy is spent on heating and maintaining the temperature of the water in it. Accordingly, when choosing, it is worth not chasing the maximum volume but proceeding from the actual water consumption and this point of view determining the optimal capacity of the tank.

Some special tables and formulas allow you to calculate the optimal volume of the tank depending on the format of use (washbasin, shower, kitchen sink ...), the temperature of the water used and other parameters. These data can be found in special sources. Here we note that the smallest storage water heaters can hold only 5 litres; such devices are designed for washing, washing dishes for 1 – 2 people and other tasks that do not require a lot of water. The average value is considered to be a volume of 80 – 100 litres, such a tank is quite enough for an apartment in which 3 – 4 people live. In the largest models, the volume is already calculated in cubic metres; such water he...aters are designed, for example, for hotel buildings, showers in sports complexes and swimming pools, and other similar places where a lot of hot water is required.

The shape of the water heater.

The traditional options are cylindrical and rectangular, but nowadays there are more specific options — flat cases, slim cylindrical devices. Here are the features of each of these options:

— Cylindrical. This form is traditional for storage water heaters. It is because with the same total volume, less material is needed for a cylindrical tank than for a rectangular one; and in production, such tanks are simple and cheap, which allows them to be used in water heaters of any price category. The disadvantages of this form include, first of all, some bulkiness in comparison with other options.

— Rectangular. The case is rectangular in shape, with pronounced front and side faces; the corners can be both sharply defined and rounded. It is the traditional form for instant water heaters, primarily gas, but it can be found in a fairly large number of storage models. Accordingly, the features of a rectangular case will be different — depending on the type of heater. So, in instant water heaters, the “rectangle” is simply one of the most convenient options in terms of the overall layout. But in storage water heaters, this shape differs from the flat one (see below) only with a slightly greater thickness and, in some cases, pronounced angles.

— Flat. A variant found mainly in s...torage electric heaters. Such devices look as if the classic cylindrical body was flattened at the back and front, reducing its thickness by increasing the width (and sometimes height). Thus, such a boiler does not protrude as much in front of the wall as a cylindrical one; in some cases, this point may be fundamental — for example, when installed in a bathroom, where a cylindrical device would hang over the toilet bowl, creating discomfort.

— Slim. A variety of cylindrical cases are characterized by a reduced diameter. In other words, boilers from this category are also round, but with the same volume, they have a noticeably smaller width and thickness than traditional cylindrical ones. In cramped conditions, this can be very useful. However, it must be borne in mind that the price for reducing the diameter is an increase in height.

Electrical power consumed by the heater during operation.

This parameter is of key importance for electric models (see "Energy source"). In them, the power consumption corresponds to the power of the heating element and, accordingly, the heat output of the entire device. The overall efficiency and flow rate of the water heater directly depend on the useful power. Accordingly, high-flow rate models inevitably have high consumption. At the same time, we note that the heating power is selected by the designers in such a way as to guarantee the necessary flow rate and water temperature. So when choosing a device according to flow rate, you need to look primarily at flow rate and temperature. Power must be taken into account when connecting: for example, if a 220 V model (see "Power source") consumes more than 3.5 kW, it, as a rule, cannot be plugged into a regular outlet — connection is required according to special rules. And the most productive and high-powered models — 10 kW or more — are connected only to three-phase mains.

The power consumption has a similar value for combined boilers — adjusted for the fact that in them the electric heater is an additional source of heat. For gas and indirect models, this parameter describes the power consumption of control circuits and other auxiliary structural elements; this power consumption is usually very small — on the order of several tens of watts, less often up to 1.5 kW.

The number of heating modes provided in the device.

This parameter is specified only for models with several heating modes. We emphasize that you should not confuse such functionality with temperature control (see "Features"). The heating mode is the general format of the device; these formats differ primarily in such parameters as the actual heating power, the number (and in combined models, and types) of the heating elements involved, etc. The thermostat, if it is in the design, allows you to change the temperature within a specific mode.

In general, the presence of several heating modes expands the functionality of the water heater but affects its cost. Of course, the specific features of these modes do not hurt to clarify in advance before buying.

The highest water temperature provided by the device. The standard temperature of hot water in the water supply is 60 °C, and this value is actually the minimum for modern water heaters: models with more modest rates (usually from 40 °C) are extremely rare. But higher values can be found much more often: for example, water heaters of 75 °C and 80 °C are very popular, and in the most powerful models in this regard, the temperature can reach 95 °C and even higher.

On the one hand, strong heating requires appropriate power (which is especially noticeable in the case of instant electric heaters). On the other hand, the higher the temperature of hot water, the less it is needed for a comfortable outlet temperature, after mixing with cold water; this reduces the consumption of heated water, which is especially important for storage boilers. In addition, many models have thermostats (see "Features").

Also, note that heating to operating values may involve different ΔT (degree of temperature change) — depending on the initial temperature of the cold water. The actual performance of the heater directly depends on ΔT; this moment is described in more detail below, in the paragraphs devoted to performance at different ΔT.

— Enamel. Like plastic, enamel is chemically neutral and does not affect the taste and smell of water, while it is considered more durable. Theoretically, this material is prone to the appearance of microcracks, including due to temperature differences (which eventually lead to water contact with metal and corrosion). However, high-quality heat-resistant enamels are most often used in boilers, which have the same coefficient of thermal expansion as the material of the tank and are damaged only in case of violation of operating conditions (or with strong impacts). So the mentioned drawback is typical mainly for the most inexpensive models with appropriate quality materials.

— Stainless steel. Due to its high strength, stainless steel is considered the most reliable and durable material today. Unlike enamelled ones, such tanks are absolutely not afraid of temperature changes, and they also normally withstand hits including pretty strong ones. On the other hand, steel is noticeably more expensive than enamel. At the same time, for such containers, the possibility of corrosion is not ruled out — especially when it comes to cheap devices that use outdated welding technologies, and the material of the seams may differ from the material of the tank. To eliminate this phenomenon, cathodic protection is required, which further affects the cost.

— Glass ceramics....Material, in many respects similar to the enamel described above. On the one hand, glass ceramic does not react with water, does not affect its taste and properties, and is also considered quite reliable. On the other hand, this material is more brittle and prone to the appearance of microcracks and the loss of its properties — both as it wears out and due to strong heating. Because of this, such water heaters usually have a recommended temperature limit of 60 °C.

— Plastic. Plastic is chemically resistant, not subject to corrosion and practically does not affect the composition of water, besides it is inexpensive. The main disadvantage of plastic coating is considered to be fragility.

— Copper. Copper coating is used exclusively in instant water heaters (see "Type"); more precisely, in such devices, the entire tank is usually made of copper. This material is not suitable for a storage tank: copper is too heavy, and it has a corrosive effect on some materials (aluminium, cast iron) due to its electrochemical properties, even if these materials are used outside the heater, in other parts of the water supply system. However, in a small tank in an instant water heater, these moments are invisible, while copper perfectly tolerates compression and tension during temperature changes.

— Titanium-cobalt alloy. A special alloy, characterized by the highest strength and resistance to corrosion, but also very expensive. It is extremely rare, only in top-level heaters.

Time to heat the storage tank (see "Type"), filled with cold water, to operating temperature.

It is worth remembering that this characteristic is not 100% accurate. Manufacturers usually indicate the heating time for certain conditions: a filled tank, maximum heating intensity, and temperature rise (∆T) by a certain number of degrees. In practice, the heating time may differ, both one way and the other. For example, if the heating time for the device is 20 minutes at ∆T = 50 °C, then when the water is heated from 15 °C to 60 °C, the time will be shorter (∆T = 45 °C). Nevertheless, this indicator allows us to evaluate the overall flow rate of the boiler, and with equal ∆T and volumes, different models can be compared in terms of heating time.