I found another source that confirms my worry about occupants´ health in renovated apartments. It is nice to save energy and money when you renovate the apartment building that you live in. You stick enough ventilation on your facade and install new plastic windows, and voila: you have saved big money. But what about the air inside your apartment? When you come to your newly renovated apartment, how do you feel inside? Do you get stuffy air, problems with dry air, etc?
Saving energy is important but not when you get bad indoor air quality (IAQ). People´s habits do not change, so think back how often you have ventilated (e.g. how often you opened your windows during the day and night) prior the renovation? Today you probably vent about the same. But it is not enough!
Veronika Foldvary´s Ph.D. Thesis from the Slovak University of Technology in Bratislava, Slovakia, proves my point!
Partial citation from her abstract: “CO2 concentration was significantly higher in the renovated dwellings that reflected lower air exchange rates in the apartments in winter. The higher CO2 concentrations and lower air exchange indicated increase of formaldehyde concentrations in the apartments. Moreover, strong association was found between levels of formaldehyde and relative humidity. These observations were linked to insufficient airing out in the apartments and occupants´ lower satisfaction with perceived air quality after renovation. In a greater fraction of the apartments the occupants ventilated as frequently as before renovation and was inadequate to achieve better indoor air quality indoors. The results of the simulations confirmed that energy renovation without considering additional ventilation, which is often the common practice, may increase CO2 concentrations in the apartments. Adding standard air handling units in bedrooms, or, at the minimum, exhaust systems in kitchens and bathrooms while at the same time keeping internal doors open, may significantly improve indoor air quality in newly energy-renovated residential buildings.”
You can read more in Veronica´s Ph.D. Thesis (link here).