Problem of windows air impermeability and air exchange through windows is currently particularly relevant. The level of comfort at home and the person’s well-being is depending on the degree of windows’ compaction.

Old windows were not particularly firm and airproof. At the same time, with all the unpleasant moments resulting from this fact, the cold air that was entering through cracks and on the one hand was warmed up in the room and absorbed the available moisture, and on the other hand when passing between the glasses together with draught it created conditions that prevented the appearance of moisture on the inside of the window and on the reveal of the door.

New windows not only alter the interior of the home but also radically change the conditions of ventilation, heat exchange and microclimate in apartment. New windows provide very tight locking. They make home much warmer, protect it from street noise, save energy needed for heating. On the other hand, they prevent "natural" air drafts, which makes it more difficult to drain excessive moisture from the premises and may cause condensation on the coldest spots of walls and glasses. New windows often bring along increased humidity in the room!

When installing new windows the energy saving must not mean giving up on the fresh air. Correct organization of air exchange means the provision of necessary controlled ventilation through the windows structures in combination with volley ventilation, and denial of wasteful and uncontrolled infiltration and unadvised ventilation that lasts for hours.

It’s recommend to regularly open windows for ventilation for a limited time (10 min.) to the owners of premises with new windows. However, as practice shows, usually it is not performed, and the desired result is not achieved. This problem cannot be solved without the technical activities, independent from the behavior of resident.

Moisture in the premises exudes from a variety of sources, the main one being the man; as a result of his breathing and sweating the air humidity is increased significantly. Large amounts of moisture are exudes as a result of washing, cooking, premise cleaning and taking a shower. Additional sources of moisture-formation are the house plants.

Source of moisture-formation                        Moisture quantity / per hour

• Person, at rest                                                            40 g/h

• Person, household activities                                       90 g/h

• Flower in the pot (avg. size)                                        10 g/h

• Cooking, cleaning and washing                                  1000 g/h

• Washing machine                                                        300 g/h

• Shower/Bath                                                                2600 g/h

• Free water surface                                                       200 g/h

Air temperature also has a great influence on indoor air humidity: temperature decrease with constant air humidity increases the relative humidity. That is, if the room temperature was 18°C and humidity of 50%, then with 17°C humidity will be 55%, and at 16°C – 60% already!! Harmful effects of high water vapor and noxious substances content are the appearance of moisture on the furniture, walls and ceilings, as well as allergic irritations and bad microclimate in the room.

Room ventilation

In large-scale housing construction the following scheme of ventilation is used: exhaust air is removed directly from the most contaminated zone, i.e. from the kitchen and sanitary premises, through natural exhaust duct ventilation. It is replaced with the outside air that enters through leakiness in external enclosures (mostly window seals) of all rooms of apartment and is heated by heating system.

Room’s doors usually open or have a door panel cutting that reduces the door’s aerodynamic drag in the closed position. For example, the gap under the bathroom and toilet doors should be of no less than 0.02 m wide. The apartment is considered as a single air volume with the same pressure.

Normalization of air exchange is executed based upon the minimal amount of outdoor air per person (approx. 30 m3/h), according to the hygienic requirements.