Comparison Electrolux EWH 50 DRYver vs Electrolux EWH 50 Heatronic Slim DryHeat

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.

— 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 warranty period declared by the manufacturer for the storage water heater tank (see “Type”).

This parameter is important for the reasons of maintenance terms. The tank is the most complex element: other parts of the water heater are relatively easy to repair and change, and if there is a problem with the tank, it is often easier to replace the entire boiler. In the most advanced models, the warranty on the tank can be 10 years or more.

The weight of the device, excluding the water collected (passing) into it.