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Ventilation systems - always fresh air in the house

Good air quality is important, both for our health and for the building: If the oxygen content is too low and instead too much carbon dioxide is in the air, we quickly feel tired and rejected, suffer from concentration difficulties and headaches; too high a humidity can quickly lead to mold growth. Therefore, the used air in every home must be regularly replaced by fresh air.

The most obvious solution is window ventilation, but only in theory does it work really well. In practice, we are usually too inconsistent, so that the air exchange required every 3 hours easily falls by the wayside. In addition, it can quickly happen that too much air is ventilated for too long and so unnecessarily much energy is lost. If you want to prevent such problems and do something good for both your health and your house, the installation of a ventilation system is highly recommended.

This ensures regular air exchange fully automatically and additionally filters pollen and other pollutants out of the air. This saves valuable energy, protects the building from mould and contributes massively to a pleasant and healthy indoor climate. Ventilation systems therefore have many advantages (but also some disadvantages), which we have summarised for you in the following overview:

Advantages of ventilation systemsDisadvantages of ventilation systems
Reduction of heating costsNot always suitable for old buildings
Decreasing house dust mite loadAcquisition costs can be high
The house becomes more allergy-friendlyRising power consumption
Air temperature can be quickly adjusted 
Noise protection, window ventilation isn´t necessary 

Types of ventilation systems

Not all ventilation systems are the same: they are available in various designs and technical variants. Two distinctions are particularly interesting for us in this context, namely the question of the construction method and the type of heat recovery.

A ventilation system can be designed centrally or decentrally, i.e. either a central device ventilates the entire building via ventilation ducts or individual rooms are ventilated separately with small devices. Heat recovery can be passive using a heat exchanger or active using a heat pump.

Central vs. decentral ventilation system

Ventilation systems can be roughly divided into centralised and decentralised designs. A decentralised ventilation system consists of two small ventilation units which are installed directly in the outer walls of the room to be ventilated. If you want to supply more than one room with fresh air in this way, you will also need more decentralised ventilation units. Since these units can be installed easily and without great planning effort, they are particularly suitable for retrofitting as part of the modernisation of an old building.

Central ventilation systems are less simple, but more efficient than the decentralised version. With these systems, all rooms in the house are connected by air ducts and supplied with fresh air via a central device. One fan sucks air from the outside into the building, another removes the used air from the rooms. Central ventilation systems are optimally planned and installed as part of a new building, as this is less complex than retrofitting. However, this is also possible, but at a higher cost.

Active vs. passive heat recovery

A ventilation system with heat recovery extracts part of the heat from the used exhaust air in order to preheat the fresh supply air. Depending on the technology used, modern ventilation systems can save up to 50 % on heating costs.

Active ventilation systems

In ventilation systems with active heat recovery, an air-heat pump is integrated into the system, with the help of which the recovered heat (depending on the specific equipment of the system) can be used in several ways:

With these appliances, the heat can be used not only to preheat the fresh air, but also to prepare hot water. If the built-in heat pump allows reversible operation, the ventilation system can also be used for room cooling. Active ventilation units are therefore truly multi-talented and suitable for a wide range of tasks.

Passive ventilation systems

Passive heat recovery works by means of heat exchangers and is the simpler of the two variants. The heat exchanger transfers part of the heat from the exhaust air to the supply air. This allows the fresh air to be preheated with little energy input.


Which design for which area of application?

Not every type of ventilation system is equally suitable for every area of application. The available options change depending on the age and condition of the building.

Ventilation system in new building

When choosing a ventilation system for a new building, you can draw on the full range of available options: In principle, any type of construction can be used, but it is particularly worthwhile here to use a central ventilation system, as these systems tend to work more efficiently and can be planned and installed directly during the construction of the house. Depending on your personal wishes, you can then choose a device with passive or active heat recovery - depending on how much you want to preheat the fresh air and whether you also want to use the system for cooling.

Ventilation system in old building

In existing buildings, everything depends on the condition of the house: There is little point in installing a ventilation system in an unrenovated old building - regardless of the type of construction. However, if the building has been renovated and complies with modern insulation standards, there is no reason why it should not be retrofitted with a ventilation system. In particular, a decentralised solution with heat recovery is ideal, as these units are comparatively easy to retrofit. If you are not afraid of the higher effort and the associated costs, there is nothing wrong with the use of a central ventilation system.

Types of ventilation systems - our conclusion

If you are not living in a draughty, unrefurbished old building, there is nothing wrong with investing in ventilation technology. Especially for allergy sufferers, a ventilation system is highly recommended as it massively improves air quality. There is a suitable design for every area of application, depending on the conditions and your personal wishes.

If, for example, you only want to ventilate a few rooms in an old building, a decentralised system with passive heat recovery is completely sufficient. If, on the other hand, you are interested in an all-round carefree package, the best choice is a central ventilation system with active heat recovery. If the integrated heat pump then still allows reversible operation, you can not only preheat the fresh supply air, but also alternatively cool it - for an optimum feel-good climate throughout the year.


Ventilation units from alpha innotec

LLG - active ventilation systems

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LLB - active ventilation systems with domestic hot water preparation

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LG - passive ventilation systems

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LD - decentralised ventilation systems

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