Comparison Kermi Therm-X2 Line-K 33 405x405 vs Purmo Ventil Compact 33 300x1100

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 manufacturer's warranty period for this model.

Usually, the terms of the warranty provide free rectification, replacement and/or compensation if the radiator fails during the stated period due to manufacturing defects. The greater the guarantee, the higher the quality of the product and the higher its cost (the latter, however, is usually compensated by high reliability). In modern radiators, the warranty period can be up to 10 years.

Note that the end of the warranty does not mean the product will immediately fail: with proper workmanship, the total service life exceeds the warranty significantly.

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.

Radiator height. The most widespread nowadays are standard height sizes: 30 cm, 40 cm, 50 cm, 60 cm and 90 cm. In addition, you can find other options (although much less often) — 20 cm, 45 cm, 55 cm, 70 cm, 75 cm and 80 cm.

Firstly, the height of the product primarily determines the size of the space required for installation. At the same time, for models placed in a niche (see "Mounting"), this dimension actually corresponds to the required depth of this niche. In other cases, it is worth taking a certain margin in height — the radiator cannot be installed close to the floor and window sill (or other similar items). And models with a bottom connection (see above) will require additional space for the pipe connection.

Secondly, this size determines heat output: all other things being equal (including the size in width), a higher radiator will have a larger working surface area and a higher heat output (this is also true for heat exchangers in convectors). Thus, modern radiators are traditionally produced not in separate models, but in series of the same type of devices that differ onl...y in size and thermal power.

Radiator width.

In modern models, this size can be from 10 cm or even less(in separately sold sections from sectional radiators, see "Type") to 2.5 m or more(in the largest panel products and convectors). At the same time, the design uses mainly standard widths — their list is very extensive, it mainly includes options in increments of 10 cm: 30 cm, 40 cm, 50 cm, 60 cm, 70 cm 80 cm, 90 cm, 100 cm, 110 cm, 120 cm, 130 cm, 140 cm, 150 cm etc. The actual dimensions may differ slightly from the standard, but this difference does not exceed 1 cm: for example, the category "60 cm" includes models with a width of 590 to 610 mm.

The width determines two features of the radiator at once: the size of the space required for installation, as well as heat output. In the first case, everything is quite obvious; we only note that the radiator heater should be placed close to surrounding objects so that it's ok to take a certain margin in width (and if the pipes are c...onnected sideward, it is worth considering the space required for them). As for heat output, other things being equal, a wider device will have a larger working surface area and a higher heat output (this is also true for heat exchangers in convectors). Thus, modern radiators are traditionally produced not in separate models, but in series of the same type of devices that differ only in size and thermal output.

The size of the radiator from the front to the back wall.

This parameter determines both the size of the space occupied by the device and its efficiency: other things being equal, a greater depth means a higher heat output (due to an increase in the area of contact with air). Specific nuances depend on the type of radiator and the method of its installation (see above). So, the most critical depth is for convectors with a horizontal layout, mounted in a niche — in them, this size directly determines both the required dimensions of the niche and the area of the working surface. In column models, this dependence is somewhat less pronounced. In panel devices, the efficiency depends not so much on the depth as such, but on the number of working elements (see "Type (panel)") — although a larger number of panels/convectors inevitably affects the dimensions. And sectional radiators most often have a relatively small depth: the differences between them in this parameter are not fundamental.