ISO 50046:2019 pdf download – General methods for predicting energy savings
4.3.2 Initial planning
Initial planning helps to ensure the feasibility of calculation. Planning the calculation process simultaneously with the design of EPIA(s) makes it possible to account for the available resources and time (in particular the budget and the timing of the decision to be made, and the resources and time required for different calculation methods). Analysis of data availability and quality is particularly important while preparing for the calculation process (see Clause 5 for more details).
4.3.3 Appropriate level of accuracy
An appropriate level of accuracy should be selected depending on the objectives of the calculations. Accuracy of the PrES is considered to be appropriate when the stakeholders have confidence in using it. It does not always need to be the highest possible level. Assumptions that make the calculations simpler and that are consistent with the calculation objectives may be used if agreed to by the stakeholders [10] . The requirement about accuracy might differ greatly, for example, between the case of an approximate estimation to evaluate whether to implement a low-investment EPIA and the case of a detailed estimation to evaluate a high-investment EPIA. The costs of calculating PrES might thus differ greatly, mainly due to differences in the resources needed to collect additional data and/or to perform additional analyses (see the example in Annex E). More details about accuracy and uncertainty are provided in Clause 8.
4.3.4 Transparency and reproducibility
To ensure transparency and reproducibility, this document identifies the information to be documented at each step of the calculation process. Documentation is the key to ensuring that the PrES can be understood and used in a correct manner. Transparency should make it possible for external experts to reproduce the calculations and results. See Annex B for an overview of documentation guidance, Annex C for an example of documentation template and Annex D for an example of using this template.
Limitations of data are a frequent problem faced in calculating PrES, particularly while using advanced methods or modelling. Likewise, many of the methodological choices made while calculating PrES can raise questions leading to a decrease in the confidence of the stakeholders in the PrES. The validation process is the key to ensuring reliability of PrES. The validation aspects are therefore highlighted at each step of the calculation process. See Annex B for an overview. The validation process should be adapted according to the context and the calculation objectives. For simple cases, the validation process might be carried out in a single meeting. In complex cases, the validation process might require iterations and different steps.
EXAMPLE In the case of building insulation, the energy performance improvement can be assessed as a change in the thermal performance of the building envelope. The result can be compared with the result of a building simulation, using recognized and proven reference values available in technical guides, or with feedback of a third party based on experience of wall insulation using similar insulation material and characteristics. In this document, the distinction is made between a check and validation. A check does not necessarily imply an agreement that the proposition is correct, while validation means that the persons/ organizations are endorsing the related decisions.