Ventilation of buildings is no longer limited to natural ventilation with the help of opening windows, although in some cases it is still an appropriate additional or the only option. Ventilation systems have become an essential part of building infrastructure. Houses that are well insulated present us with a challenge, because without mechanical ventilation they do not allow sufficient air flow, which can negatively affect the quality of living.
International standards and national legislation stipulate that it is necessary to provide at least 15 m³ of fresh air per hour for each person, and the recommended value is twice as high. The regulation on ventilation and air conditioning stipulates that at least 50% of the air volume per hour must be replaced in living spaces.
The promotion of energy efficient construction has resulted in modern buildings using much less energy for cooling and heating compared to older buildings. Even technical regulations (e.g. the European directive on almost zero-energy construction) indicate that there is no modern house without mechanical ventilation (with heat recovery). The emphasis is still on airtightness, because we simply can no longer afford windows that are poorly sealed and let air in. It is recommended to install mechanical ventilation systems that ensure a continuous supply of fresh air and the removal of the same amount of used air from the building. In a press release, the European Commission warned that substances found in closed and poorly ventilated spaces can cause asthma and other allergic diseases, which, according to their estimates, affect up to 20% of the population.
With central ventilation systems, the air is changed more efficiently than with local ones, which means greater efficiency. In addition, central systems have a higher proportion of heat recovery compared to local ones. Some local heat recovery units allow the installation of one unit containing a heat exchanger. The fan in these units works by first sucking air out of the room for a while, then changes the direction of rotation and supplies fresh air that is preheated on the heat exchanger. Other units require installation in pairs, with both recuperator units operating simultaneously.
In the case of natural ventilation, such as opening windows, it is recommended to fully open all windows (for a draft) at least 5 times a day for a short time (2-5 minutes) in order to change the air in the room and prevent hypothermia. In this case, it is best to open all windows and doors so that the air can be exchanged also from the corners and behind the furniture, otherwise water vapor can accumulate in the room (due to activities, breathing, cooking), which can lead to condensation on cooler surfaces and the formation of mold. In the case of activities that release more moisture (e.g. steam ironing, drying laundry, cooking), it is recommended to ventilate the room immediately after finishing the work. It is also important that the furniture is not placed against the external walls, as air exchange is poor when in contact. It is ideal to place the furniture about 5 cm away from the wall. Nevertheless, natural ventilation is not optimal, as regular ventilation may be forgotten or it may not be carried out often enough in the colder months due to the cold. Since it is recommended that the air in the rooms is changed even when they are not in active use, some users choose an automatic window opening and closing system. Such a system makes it possible to ventilate the premises a few minutes before arriving home and to heat or cool the premises to the appropriate temperature. This can only be a temporary solution. It makes more sense to consider investing in a mechanical ventilation system, either with heat recovery or a hygrosensitive system.
Ventilation with recovery also enables additional heating or cooling of the supplied air, which is especially useful in small passive houses or apartments that do not need additional heating or cooling systems. Ventilation systems with recovery are becoming more and more popular, as they allow maintaining a higher thermal efficiency. Here, it is important that the ventilation system works continuously, as switching it on and off from time to time will not bring the expected results. It is also crucial that the thermal efficiency is as high as possible, as it can decrease significantly after a few seconds if the system is not set up correctly.
In Slovenia, ventilation without returning waste air heat is fundamentally wasteful due to climatic conditions. Forced ventilation makes the house more economical, helps save on heating and prevents moisture, excessive CO2 concentration, the appearance of mold and unwanted emissions in the air. The investment in the ventilation system can pay for itself in 10-15 years and is an investment that should work for several decades, so when building or renovating a building, it is one of the key ones that can benefit both users and the environment in the long term.
For more information or a consultation, please contact us; Phone: 00386-40-626-131, E-mail: tajnistvo@bazarealestate.com.
