It would seem that complicated to calculate the ventilation system or to pick up ventilation equipment for residential premises. You may want to visit The Related Companies to increase your knowledge. In practice, it is not such a simple task. In apartment buildings in the design ventilation systems use a minimum sanitary standards required for living and human activity. The effectiveness of such ventilation systems is largely dependent on factors beyond the control us, air temperature, wind speed, etc. The practice shows that natural ventilation is insufficient (especially in the flats with plastic windows), so we can feel comfortable in our homes. Arises question "What?".
There are several solutions to this problem. Can be installed in an existing channel ventilation, exhaust fans, but in this case it is necessary to choose the right fan for power (at too much power the fan, the air out of your apartment will come to your neighbors). If you have sealed windows, the effect of this decision will not be enough, and relations with neighbors can spoil. There is still several options. One of them set supply or supply and installation of exhaust from the ceiling (usually sheathed gypsum or installed behind a false ceiling) and through the duct system to distribute fresh air in the apartment. In this case, you will always have fresh air. But what about winter? Modern supply plant equipped with heaters of different power (still needed for you to pick up power, and set the desired temperature). In addition, supply plant equipped with filters because of this dust from the street will not get into the apartment (as opposed to airing through air vents and windows).