This theoretical study reports on the impact of perceived indoor air quality for productivity loss in air-conditioned office buildings. A new derivation of productivity calculation model based on pollution loads and contaminant removal effectiveness is applied and the effect of the improved ventilation efficiency on productivity is estimated. The findings show that the proportion dissatisfied is a good predictor of productivity loss due to indoor air quality in different kinds of office work. It is possible to calculate the proportion dissatisfied from olf and decipol units. Productivity is possible to improve by increasing outdoor airflow rate, decreasing emissions and improving ventilation efficiency e.g. with displacement ventilation. In a case of one person per 10 m 2 (0.1 olf/m 2) and low-emitted material (0.1 olf/m 2), the total sensory pollution load is 0.2 olf/m 2. Normally, the minimum admissible outdoor airflow rate is 0.5–1.5 l/s per m 2 in office spaces. This means that 5–9% productivity loss should be accepted using the minimum airflow rate design method. With displacement ventilation, it is possible to improve indoor air quality in a manner that significantly increases productivity compared with traditional mixing system. The effect of the contaminant removal effectiveness on the productivity loss is about 0.5–2% between these systems using the same airflow rate.