How to choose a water heating radiator

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In this article, we will try to determine the main criteria that must be followed when choosing hot water radiators. Indeed, not only the temperature and humidity of the air in the room depends on what equipment is installed in the apartment, but also the size of utility bills, the aesthetic appeal of rooms and even the health of family members.

How to choose a water heating radiator

Heat transfer in nature is carried out in three ways: by transferring heat from one body to another – thermal conductivity, due to the transfer of heat in gases, bulk media or liquids by flows of matter – convection, and due to the electromagnetic radiation of a body, which is in a state of thermodynamic equilibrium – thermal radiation.

Naturally, the action of any heating system is based on one of the above physical processes. So, in all houses built in the Soviet and post-Soviet times, heat enters the apartments by natural convection: heated hot water rises up into cast-iron batteries, and cold water returns to the boiler. Despite the fact that this scheme is extremely ineffective, it continues to be used to this day.

A water heating radiator, colloquially referred to as a battery, is a heating device with which almost all living quarters are equipped. The radiator consists of several sections, inside which there are internal channels through which the coolant circulates. Heat from this heater is transferred by radiation energy and convection.

The word radiator comes from the Latin radiator, which means “radiator”.

The most common types of radiators used in Russia today are:

  • cast iron;
  • aluminum;
  • bimetallic;
  • steel panel.

From the names it is easy to understand that the main difference between these radiators lies in the material from which they are made..

If you decide to change a water heating radiator, then you need to get more detailed information about each type of radiator, as well as find out some data about the heating system of your home. In particular, you should definitely inquire about the ph level in the coolant, the operating and test pressure of the system, the temperature of the water in the heating system, the diameter of the pipes supplying the coolant to the radiator..

Cast iron radiators

The advantage of cast iron radiators is their high corrosion resistance. The fact is that during operation, dry rust forms inside the radiator from cast iron, which protects the battery from the effects of an aggressive environment. In addition, cast-iron radiators have a low level of abrasive wear, which is why they are not afraid of debris that gets into heating equipment, a highly alkaline environment, etc..

Cast iron radiators

The working pressure of cast iron radiators is 6-9 atm, the test pressure is 15-18 atm, the maximum temperature of the coolant is 130 ° С.

The advantages of this type of water heating radiators are also considered to be relatively low cost, high heat transfer and durability. So, manufacturers guarantee that a cast iron radiator will last at least 30 years..

The disadvantages of a cast iron battery, first of all, are the low thermal conductivity of the metal and a small heat transfer surface. In particular, the standard section of the M-140 cast-iron radiator (Russia) weighs 7.5 kg and holds 4.5 liters of water, but the heating area is only 0.23 m2, whereas, for example, a 2-kilogram aluminum radiator with a water volume of 0.5 liters heats about 0.4 m2.

The large thermal inertness, which does not allow cast-iron radiators to cool down quickly, rather refers to the disadvantages of this heating equipment, since such batteries are completely unsuitable for regulated automatic water heating systems.

The disadvantages of cast-iron radiators include vulnerability to hydraulic shocks, the weight of the sections and the design of the equipment, which is sometimes very problematic to fit into modern interiors..

Aluminum radiators

Aluminum sectional radiators, made of aluminum alloy with the addition of silicon, have become very popular in recent years, mainly due to the attractive dimensions and weight of this heating equipment..

Aluminum radiators are produced in 2 versions: cast and extrusion. In the first case, each section of the radiator is cast as a single piece, in the second – the section consists of several parts.

Aluminum radiators

The advantages of aluminum radiators for water heating include a high level of heat transfer and a speed of heating the room, which allows us to speak of a 30% saving in energy consumption.

These radiators have a low weight, elegant design and high operating pressure (up to 25 atm, some 60 atm), and the cost of the radiator depends on the parameters of the operating pressure: the higher it is, the more expensive the radiator.

The indisputable advantages of aluminum radiators are the ability to choose equipment with the required number of sections and thermoregulation.

However, light and beautiful aluminum radiators have their drawbacks. In particular, they are susceptible to electrochemical corrosion: if the equipment is installed incorrectly, aluminum enters into a chemical reaction with steel pipes, the same applies to copper pipelines. In addition, the chemical composition of the coolant also affects the service life of aluminum radiators, the optimal ph level of which should be 7-8.

To improve the properties of heat transfer, manufacturers make the walls of aluminum radiators thin, so the section can burst from an impact of medium power, which also refers to the disadvantages of aluminum radiators.

Steel panel radiators

Steel panel radiators are two stamped steel sheets with a thickness of 1.5 mm. Steel sheets are joined to each other either by horizontal collectors connected by vertical columns, or by horizontal channels, which are welded in parallel and in series to one panel.

Steel panel radiators

The working pressure of steel radiators is designed for 6-10 atm, the maximum temperature of the coolant is 110-150 ° С.

Steel panel radiators are characterized by high heat dissipation and low thermal inertia. They are best used in closed water heating systems, since they have increased hydraulic resistance..

The main disadvantage of steel radiators is accelerated corrosion (under the most favorable conditions, the corrosion rate of steel per year is 0.1 mm), which very quickly destroys the metal in the plate welding areas.

The disadvantages of steel radiators are also considered to be low operating pressure and a small heating surface area..

Bimetal radiators

In the manufacture of bimetallic heating radiators, two metals are used: steel and aluminum, hence not only the name follows, but also the absence of disadvantages inherent in steel and aluminum radiators.

Bimetal radiators

Due to the fact that the pipes of the bimetallic radiator are made of steel, the coolant does not come into contact with aluminum, this avoids negative chemical reactions, and as a result, corrosion.

The main advantage of bimetallic radiators is the high degree of heat transfer provided by aluminum.

Bimetallic radiators are often used in systems with increased pressure, because the working pressure of the radiator can withstand 25 atm.

The disadvantages of this type of heating equipment include high cost, small diameter of internal channels, as well as presence on the market of the so-called. “Semi-bimetallic” radiators, which sellers pass off as bimetallic radiators, but the difference between them is significant. Bimetallic radiators are made of a one-piece welded steel frame, which is filled with aluminum alloy, horizontal collectors and vertical channels in them are a steel welded structure. In “semi-metallic” devices, steel pipes reinforce only vertical channels, which weakens the strength and resistance of the radiator to corrosion.


To calculate the radiator power required for a room, the following formula is used: Q = S? 100 W, where S is the area of ​​the room.

This formula is applicable for residential buildings with one window and one door, the ceiling height in which does not exceed 3 m.If the apartment is angular, then the formula for the calculation will look like this: Q = S? 100 W? 1.6, if the apartment is installed plastic windows – Q = S? 100 W – 200 W.

You should also take into account other important points:

  • it is recommended to place a radiator under the windows, the size of which is at least 50-75% of the width of the window opening;
  • when installing the radiator by the window, the gap between the floor and the equipment should not be less than 6 cm, between the window sill and the radiator – 10 cm;
  • in large rooms it is better to install two radiators.
Read more  How to choose a wall-mounted gas boiler for heating a private house
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