Evaluation methods for indoor environmental quality assessment according to EN15251

In existing and future buildings there will be an increasing focus on energy uses and indoor environmental quality. Even if buildings are using several different kinds of energy sources, the yearly energy performance is expressed in one format either as primary energy or CO2 emission. As a consequence, in order to compare energy performance with the corresponding indoor environmental performance, there is a need to express also the indoor environmental performance on a yearly basis, referring both to each separate environmental factor (thermal comfort, air quality, light and noise) and to a combination of these factors. If the indoor environmental criteria in existing standards have to be met 100% of the occupancy time, the amount of heating, cooling and/or ventilation capacity of any HVAC installation would be prohibitive in terms of energy consumptions. Economic and/or environmental considerations lead to a more pragmatic position of allowing the indoor environmental conditions to exceed the recommended ranges for a limited period of time: this can be verified both by computer simulations (design stage) and by the field monitoring (post-occupancy phase). The present paper will present some concepts to carry out a whole year performance evaluation of the indoor environment, inspired by ISO EN 7730 (thermal environment) or EN15251 (thermal, indoor air quality, light and noise). Besides, some new suggested concepts about indoor environmental quality are tested. Based on data from indoor environmental measurements in an existing building, methods for long term evaluations will be presented and discussed. The results show that the different concepts to a great extend will bring the same relative results. The results also show that today we still do not have enough knowledge to be able to combine the indoor environmental parameters into one synthetic indicator.