Why is the calculation of the overall energy performance of a building split into separate EPB standards?

Why is the calculation of the overall energy performance of a building split into separate EPB standards and not combined into an all-in-one standard (at least all EPB standards that are part of the overall EP calculation)?

In general, the ISO and CEN standards making process is handled by various technical committees or TCs as they are called. The TCs are the key bodies that drive the standardization and comprise experts from the national committees. Each committee is responsible for a specific work area. This ensures a transparent and fair process, having the right experts involved in the development and review of each standard and the right links to the experts in so called national mirror committees. Having said that, joint working groups can be formed between committees in case of standardization work of joint interest.

For the set of EPB standards, the expertise on the overall energy performance is divided in CEN over 5 TCs (building and building components, heating &DHW, ventilation & cooling, BAC and lighting) and also in ISO different TCs are involved.

To coordinate the work aiming at a consistent overall energy performance calculation, a coordinating TC was formed in CEN (CEN/TC 371) and in ISO a coordinating joint working group (ISO/TC 163/WG 4, joint with TC 205) and joint advisory group (ISO/TC 205/AG1, joint with TC 163) were established. In turn, there is close collaboration (including task distributions) between ISO and CEN.

From the start of this coordination work the aim was to go for a modular approach: a matrix in which each element covers a specific part of. the overall energy performance assessment (not only calculation, but also measured EP, inspection, economic evaluation and related aspects).

Ideally, each module is one EPB standard, but for practical and historical reasons this is not always the case. Each of these standards is subject to specific technical and editorial rules provided in the overarching EPB standard, (EN) ISO 52000-1 and in complementary quality documents, to ensure overall consistency.

The modular approach ensures that each country can follow a step-by-step procedure to implement the overall EPB assessment procedures (successively replacing national procedures by the procedures in the set of EPB standards).

Moreover, in the modular approach the need for updating a specific element in the calculation (for example on ventilation systems, heat pump system or thermal transmittance of windows) can be addressed by the specific experts and interested parties in the specific technical committee and result in a proposal for revision of that standard and publication. In case of an all-in-one EPB standard a revision of one chapter would implicate that the whole all-in-one document would need to be revised (and purchased…).

Besides, many users are interested in only a specific aspect of the overall energy performance assessment. For them it would become very costly if they would need to buy “all-in-one”.

Of course, it is essential that the whole set of EPB standards, in particular to calculate the overall energy performance of a building, is consistent and complete. This is, however, not different from an all-in-one document to assess the overall energy performance of buildings, that would still be the combined result of contributions from many experts.

2022-02-07