Problems with an unpleasant environment in poorly ventilated rooms are quickly solved by opening the windows. Sometimes, however, it is redeemed by an influx of dust, noise, allergens or odors from outside. In winter, cold also flows into the house, which raises the heating bill. The optimal solution can be the installation of controlled ventilation with heat recovery (recovery).
The equal pressure controlled ventilation system with heat recovery is technically more complex than other methods of building ventilation. Compared to open windows, however, it offers the possibility of regulating the air intake and exhaust according to the user's requirements, the concentration of pollutants (CO2, water vapor, etc.), cleaning the outdoor air with filters and possibly adjusting its temperature. The main advantage is significant energy savings, in which it has the upper hand over other forced ventilation systems.
According to Daniel Adamovský from the University Center for Energy Efficient Buildings of CTU, heat consumption for ventilation in ordinary family and apartment buildings built in accordance with current standards accounts for a third to a half of the costs of heating and hot water preparation. Depending on the efficiency of the recovery system, it is possible to save up to 85% of the energy on average, which is necessary for heating the ventilation air and has a direct effect on maintaining a pleasant temperature in the interior.
The principle of the device is simple. One fan is used to remove air at a temperature of around 20 °C from the house, mainly from the bathroom, toilet and kitchen. At the same time, the second fan brings cold outside air into the building, the temperature of which can be well below freezing in winter. Both air streams simultaneously flow through the recovery exchanger, in which the waste air transfers its heat to the fresh air through the separating heat exchange surface, without mixing with it and contaminating it with harmful substances or odors. Therefore, considerably less heat is needed to heat up the supplied air to room temperature.
In hot weather, the recovery heat exchanger can be simply taken out of operation without the system ceasing to perform other functions. Even in summer, there is no need to open the windows for fresh air. All year round, it is possible to regulate the ventilation performance according to the current occurrence of pollutants in the house and to adjust the air with filters. Thanks to this, it is not a problem to avoid drafts, odors, pollen load and noise, which is especially appreciated by residents of houses and apartments located near busy roads, buildings, factories, blooming fields, restaurants, etc.