Estimate of an economic benefit from investment in improved indoor air quality in an office building

Life-cycle costs of investments for improving air quality in an office building were comparedwith the resulting revenues from increased office productivity; benefits from reduced healthcosts and sickness absence were not included. The building was simulated in a cold, amoderate and a hot climate. It was ventilated by a constant air volume system with heatrecovery. The air quality was improved by increasing the outdoor air supply rate and byreducing the pollution loads. These upgrades involved increased energy and maintenancecosts, first costs of a HVAC system and building construction costs. But the additionalinvestments were highly cost-effective: productivity benefits resulting from a better indoor airquality were up to 60 times higher than the increased costs; the simple and discounted paybacktime was below 2.1 years; and the annual rate of return was four to seven times higherthan the minimum rate set at 3.2%. The present data, although obtained by simulations,constitute a strong incentive for providing indoor air of a quality that is better than theminimum levels required by present standards.