Impacts of Energy Retrofits on Ventilation Rates, CO2-levels and Occupants' Satisfaction with Indoor Air Quality

INSULAtE-project assessed impacts of energy retrofits on indoor environmental quality and occupants' satisfaction. Most common retrofit actions included changing new windows and installing heat recovery into exhaust ventilation system. This paper presents results related to ventilation in Finnish apartment buildings before and after the retrofits. Average ventilation rates (from exhaust vents) in buildings with mechanical ventilation were 0.43 ACH before and 0.48 ACH after the retrofits. Average CO2 concentrations were 750 ppm before and 715 ppm after the retrofits, correspondingly. Percentage of occupants satisfied with IAQ was 22% before and 41% after the retrofits. In conclusion, ventilation rates, CO2-levels, and occupants' satisfaction with IAQ were improved in most retrofitted buildings.