Selection of a water heater

Selection of a water heater

The key to the correct operation of the heating system is its correct selection. Of course, heating devices now have a wide adjustment range and can operate efficiently at various power supply parameters of the system. Nevertheless, it still has its limits. If the heating power of the receiver installed in the room is too low, during the periods of strong frost the room will be inadequately heated. Oversizing will result in too high temperature or the heating timing that is harmful to many devices – activating heating in short cycles.

Determination of the heat demand

The first, basic step in the selection of water heaters is to determine the demand for heating power in the room and the amount of energy delivered during the season. There are many methods to determine this value. The simplest one is to multiply the room cubic volume (V) by the desired temperature rise (ΔT) and the building insulation factor k.

Q [kcal / h] = V x ΔT x k

to convert the result into kW, multiply it by 1.163. The next step is to choose a product from the manufacturer's catalogue.

However, these are very general calculations, based on an estimation of the quality of the building's insulation – since k usually takes values from 0.5 for well-insulated rooms to even 3-3.5 for poorly insulated buildings.

The best solution in this regard is a comprehensive analysis of the building's heat demand, based on the parameters of the materials used for its construction. On the basis of its documentation, you can precisely determine the losses from each room and choose the best suited heat receivers. This type of analysis will probably require some costs, but they can be recouped by choosing the right heating system.

Simplified selection of a water heater

A large range of water heater adjustment means that this product should work properly even if it is selected with less precise methods. Independent calculations may be enough, but it is worth comparing them with the selection tools provided by the manufacturer. Also on our website, at, you can find a convenient system for adjusting the sonnEC water heater for the needs of the room. All you need to do is enter its surface and height, location and the desired internal temperature. The precision of selection can be additionally increased by determining the supply and return temperature of the system – e.g. 90/70 for boilers or 50/30 for heat pumps. It is also important to properly determine the insulation.

The result of the calculations is the proposal of the best solution from the NEUTEC brand assortment. After specifying the work schedule (number of days per week and hours during the day), you can also see a comparison of the costs of using a modern heater with an EC fan and a device equipped with an AC fan.

Selection is not all

In the case of air heating, it is also necessary to ensure the proper arrangement of its elements in the room. Thanks to this, heat can be quickly delivered to selected zones, and at the same time its losses can be minimised – for example due to the escape of heated air to the ceiling. In addition, the requirements concerning the maximum air flow velocity in zones used by people must be observed.