Why is it important to have a standard on Indoor Environmental Quality as part of the EPB standards?

The Indoor Environment is mentioned several places in the 2010 EPBD recast (Table 1). To fulfil these requirements and to safeguard an acceptable and healthy indoor environment the standard EN16798-1 “Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics” has been developed. The first international standard that dealt with all indoor environmental parameters (thermal comfort, air quality, lighting and acoustic) was published in 2007 as EN 15251. This standard prescribed input parameters for design and assessment of energy performance of buildings and was a part of the set of standards developed to support the implementation of the Energy Performance of Buildings Directive from 2003 in Europe. This standard has now been revised and will be issued for formal vote with a new number: FprEN 16789-1:2016. To support and give more detailed guidance for the use of the standard, a Technical Report, prCEN/TR16789-2 is also being developed. The standard is now written in normative language and all the informative text is included in the technical report. The standard includes default criteria given as 3 to 4 categories for the indoor environmental parameters. The values for the recommended default criteria are listed in tables in an informative annex B. Individual countries can decide if they want to use these default values, only use one category, or use quite different values, which then will be included in a national annex A with similar structure as annex B.

The standard includes both criteria for design and input values for energy calculations as required in the recast EPBD (Table 1, Annex 1–3). These criteria are established based on the preferences and expectations of the occupants and are basically independent of the building and systems used.

The EPBD refers several places to “cost-effectiveness”. The standard for indoor environment does not address this directly. It is however important to be aware of the fact that in an office the energy costs for heating-cooling-ventilation is only 1 % of the salary costs. It is also well known that the indoor environment has a significant influence on people’s productivity, so just 1% decrease of productivity will be equal to the total energy budget. This means any investment that will improve the indoor environment and increase productivity is cost effective. The technical report will include some information on this.

The recast also mentions the importance of “natural daylight” and “natural lighting” (Table 1, para 9, Annex 1–4). This is now also included in the standard, where minimum requirements and categories of daylight factors are included.

For energy calculations the result will also depend significantly on the assumed occupant schedules. It may then be very difficult to compare same type of building if different occupant schedules have been used in the calculations. Therefore, the standard list several recommended default occupant schedules for different type of spaces like residential, offices, schools, restaurants, meeting rooms, department stores, etc. The schedules include criteria for the indoor environment based on the default values, time and level of occupancy and internal loads from other equipment.

Although users or national regulators can choose different indoor environmental criteria as basis for the design or Energy Performance assessment, this standard will make it clear that when comparing different building constructions and building service systems on which input values for the indoor environment the comparison is based.

Buildings are for people and building service systems and building envelope must provide an acceptable indoor environment.

Table 1.Excepts from the EPBD Recast (DIRECTIVE 2010/31/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 19 May 2010) on the energy performance of buildings.