Indoor Air Quality in energy-efficient buildings in Sweden: comparison with the Swedish residential housing stock and new conventional buildings

The aim of this study was to compare the indoor air quality in newly built energy-efficient (passive) buildings in Sweden with the Swedish residential housing stock and new conventional buildings. We have used data from our previous publications to calculate Indoor Environmental Index (IEI), which is an average of Indoor Discomfort Index (IDI) that regards temperature and relative humidity, and Indoor Air Pollution Index (IAPI) that regards concentrations of indoor air pollutants. The passive building had significantly worse IEQ than the housing stock (p <0.05). Further disentangling of the partial indexes revealed that the difference was almost entirely caused by low to very low relative humidity in the passive buildings which affected the IDI. It could be speculated that the low relative humidity is coupled to operation of the ventilation systems and air exchange rates. It might be of importance to review the ventilation requirements in the energy-efficient building