Comparison Purmo Ventil Compact 33 300x1400 vs Kermi Therm-X2 Profil-K 22 300x1400

The country of origin of the brand.

In most cases, either the homeland of the brand or the location of the manufacturer's headquarters is indicated as the country of origin. Production facilities may well be located in another country. However, it is worth noting here that most of the national stereotypes nowadays are unfounded — the quality of products depends not so much on geography but on the characteristics of the organization of the production process in a particular company. So from this point of view, when choosing, you should focus primarily on the reputation of a particular manufacturer. It makes sense to pay attention to the country of origin of the brand if you fundamentally want (or do not want) to support a company from a certain state.

Nowadays, the production of radiators is mainly carried out by companies from such countries: England, Belarus, Belgium, Germany, Holland, Spain, Italy, China, Norway, Poland, Turkey, Ukraine, Finland, Czech Republic.

The type to which the panel radiator belongs (see Radiator type).

The type is indicated by a number that describes the number of heating panels and convectors in this model. Panels occupy the entire height and width of the radiator, and convectors are special zigzag structures between panels that improve heat output. As for the designation itself, the first digit in it corresponds to the number of panels and the second to the number of convectors. For example, the popular type 22 provides 2 panels and 2 convectors between them (the convectors are located inside the radiator, each is attached to its panel), and in the less popular type 21, there is only one convector, respectively, common to both panels. There are options without convectors at all — for example, the simplest type 10, with just one panel. And one of the most advanced today is type 33, more convectors/panels are extremely rare.

In general, more elements (with the same device size in width and height) improves the overall efficiency of the radiator but it comes at the expense of price, depth, and weight.

Radiator operating pressure.

This term usually means the highest pressure of the heating medium that the radiator can sustain without consequences for an indefinitely long time. Higher rates are also allowed for a short time (see "Maximum pressure"). However, the standard operating pressure in the heating system should not exceed the specs of the radiator; otherwise, the product is likely to be damaged. In general, it is believed that this indicator should be at least 2 bar higher than the actual working pressure in the system — this will give an additional margin of safety in case of emergencies.

The highest heating medium pressure that the radiator is capable to sustain without consequences during short-term exposure.

This figure is always greater than the operating pressure (see above). It directly shows the resistance of the product to emergencies, primarily the water hammer. Other things being equal, higher maximum pressure means greater strength and reliability — however, such radiators are more expensive.

The volume of water or other heating medium required to fill the radiator.

This information is relevant mainly when building an autonomous heating system: it is useful when calculating the total volume of heating medium in the system and related parameters. If the radiator is purchased for use in centralized heating, you can not pay much attention to its internal volume.

The maximum heating medium temperature allowed for a radiator is the highest temperature the product can withstand without consequences for a sufficiently long time.

The maximum temperature for heating systems (both centralized and autonomous) is +95 °С as standard. Thus, most radiators have an upper temperature limit of +110 ... 120 °C — this allows you to withstand such conditions confidently.

How to connect a radiator to a heating system. It is indicated by the location of the inlets for connecting the supply and return.

In modern radiators, both side and bottom connections are found. In the latter case, the inlet and outlet pipes can be located both on the sides (on different sides of the structure) and in the centre, side-by-side. Anyway, this feature does not affect the functionality and specs of the radiator. At the same time, it must be borne in mind that the sideward connection can involve both one-sided and dual-sided (from different sides) pipe connection; many models allow both options at once, to choose from, but this point needs to be specified separately.

Note that the available connection methods depend to some extent on the type of radiator (see above). For example, panel devices can have any type of connection, and in sectional products, the sideward method is mainly used — other options are extremely rare, mainly in models of a specific design.

The distance between the axes of the inlet and outlet manifolds of the radiator or its separate section.

The dimensions of the product and the possibility of installing the heater in specific conditions, taking into account the peculiarities of the pipe connection, directly depend on this parameter. The parameter is indicated mainly for models of traditional design - with two horizontal pipes at the top and bottom, between which vertical channels of the heat transfer are laid. The centre distance determines at least the overall height of the product, and in radiators with sideward connection (see the corresponding paragraph), it also determines the features of the organization of this connection.

As for specific values, the most common models in our time are 250 mm, 350 mm, 450 mm, 550 mm and 850 mm. Solutions for 150 mm, 400 mm, 500 mm and 700 mm are noticeably less common.

The rated thermal output of the radiator is the amount of heat given off to the air in normal operation.

When choosing this parameter note that the heat output will depend on the temperature difference at the inlet and outlet to the radiator, as well as on the ambient temperature. The greater the temperature difference and the colder it is around, the more intense the heating will be. Therefore, in the specs, it is customary to indicate heat transfer for certain standard conditions. In particular, the designation according to the European standard EN-442 is very popular, which assumes heating medium temperatures of +75 °С and +65 °С at the inlet and outlet, respectively, as well as an air temperature of +20 °С. Real conditions and the actual heat output of the radiator may differ; therefore, when choosing, it is best to choose a model with a certain margin and compensate for excess power with one or another regulator. As for the actual values, in the most modest models, the heat outputdoes not exceed 750 W, or even 500 W, and in the largest, this figure can reach 3.5 – 4 kW or more.

The choice for this parameter depends primarily on the size and specs of the heated space. The simplest calculation formula is as follows: at least 100 W of thermal power is required per 1 m2 of area. This formula is relevant for standard r...esidential/office premises with ceilings of 2.5 – 3 m, without problems with thermal insulation; for more specific conditions, there are more detailed calculation methods, that can be found in special sources.