Comparison Atlantic Vertigo Steatite 50 vs Electrolux EWH 50 Centurio IQ

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 presence of 2 water tanks in the storage water heater; usually, the total volume is divided equally between these tanks.

This design is noticeably more complex and expensive than the traditional 1-tank arrangement but offers several advantages. Firstly, the tanks can be heated in turn, which significantly speeds up the process. After all, for hot water to be used, it is enough to warm up only half of the total volume to the operating temperature. Secondly, with this format of work, power consumption and the load on the power grid are reduced. And if at a certain moment, the user does not need a lot of water, then the energy consumption turns out to be small (again, because the entire volume does not need to be heated). Thirdly, compared to traditional models of the same volume, such boilers are thinner, which can simplify installation (the price for this advantage is an increase in width, but this moment is not so often critical). Fourth, this arrangement improves thermal insulation and reduces heat loss.

This parameter characterizes the efficiency of electricity consumption by the water heater. Classes are indicated by latin letters from A to G (A, B, C, D), where A is the most energy efficient device.

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 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.

The number of heating elements provided in the design of the water heater. In this case, it is the total number of elements that are taken into account, regardless of whether they belong to the same type or different ones: for example, 2 heat exchangers and 1 heating element are considered as 3 elements.

All gas models (see "Energy source") have only one heating element — this is quite enough for efficient operation. In combined devices (see ibid.), on the contrary, there are several heating elements by definition (at least two — a heat exchanger and an electric one). In electric and indirect water heaters, the options may be different.

The meaning of several heaters of the same type is primarily to increase the heating efficiency. For example, in an instant (see "Type") electrical water heater, in this way, it is possible to increase the working length — the distance that water passes inside the device from inlet to outlet; by increasing the working length, the water is heated longer. In storage electric models, several heaters provide more uniform heating of the water, and in indirect ones, they allow more heat to be taken away. In addition, in indirect devices, heat exchangers can differ in the source of heating: for example, one can work from a heating boiler, the second from a solar collector.

Also, note that duplication of heating elements can also be used as protection against failures: if one of them...fails, the heating efficiency decreases, but the device remains operational. However, this possibility is not available in all models with several heaters, its presence should be clarified separately.

— Open coil. The open coil is made from a high-resistance electrical wire enclosed in a thin insulating sheath. The main advantages of such an element are the heating rate, high efficiency and precise temperature control; in addition, scale is almost not formed on the spiral. And of the shortcomings — a low service life.

— Wet heating element. Wet heater is a metal tube with a heating thread laid in the centre; the space between the tube and the thread is filled with an insulating material with good thermal conductivity. Heating elements heat up more slowly than open coils, have lower efficiency and are prone to the formation of scale on them; on the other hand, their service life is much longer, and in instant heaters, heating elements are not so sensitive to air pockets.

— Dry heating element. A kind of heating element with an improved design: the heater tube is enclosed in an additional shell (most often made of metal with an enamel coating on the outside) and does not come into contact with water, hence the name. Thanks to this, the likelihood of scale formation is reduced, which is especially important when working with hard water. Also, the replacement of such elements is significantly easier than conventional ones. Among their shortcomings can be called a rather high cost.

— Infrared heating element. Tu...bular electric heater of a special design: in the form of a transparent glass tube, in which the incandescent spiral is enclosed. The principle of operation of such an element is somewhat different from a conventional heating element: a significant part of the heating is provided by infrared radiation, which heats not so much the water as the walls of the tank — and heat is already transferred from them to the water. Thus, the water is heated not only at the point of contact with the heating element but also at the point of contact with the walls — which means that the heating is faster and more uniform. Also, note that the IR heater itself is usually "dry"; see above for the advantages of this design. The main disadvantages of such heaters are high cost and relatively short service life.

— Heat exchanger. It is used in gas and indirect heaters (see Water heater type). It is a metal structure heated by burning gas (in gas heaters) or passing inside a heated coolant (in indirect heaters). Usually has a ribbed shape. It is done to ensure the maximum area of contact with the heated water with relatively small dimensions — the larger this area, the more heat is transferred to the water per unit of time and the more efficient the heater is.