B-20 Operational energy demand for existing buildings – Boundaries and scenarios

*Aspect*		B-20 Operational energy demand for existing buildings – Boundaries and scenarios
*Description*		Several parameters can influence the results of the energy demand at the operational stage of buildings. Among others, the selection of uses (i.e. building-related or non-building-related uses) has a major significance on the energy demand. European standards (EN 15804/EN 15978) recommend that priority be given to taking building-related uses into account; however, it is obvious that non-building-related appliances significantly influence the energy needs of building-related uses (e.g. the thermal gain of appliances decreases the level of heating demand). Moreover, the global gain obtained by technology mixing building energy uses and non-building-related uses (e.g. appliances such as dishwashers and washing machines using domestic hot water produced by solar thermal panels) can be taken into account only if all operational energy uses are also considered into the assessment. The following section aims at providing guidance for screening, simplified and complete LCA of existing buildings.
*related study objective*		☒ stand-alone LCA		☒ comparative assertion
*related study phase*		☒	☐	☐	☐	☐
		goal and scope definition	inventory analysis (LCI)	impact assessment (LCIA)	interpretation	reporting
*relevant for*
	new buildings	existing buildings	construction products	screening LCA	simplified LCA	complete LCA
*Provisions*	For existing buildings, measured historical data consumption should be used, if available and applicable. Building-related uses and non-building-related uses may be taken into account according to the goal and the scope of the study.
*Rules from:*	*EN 15978: 7.4.4.7 Boundaries for operational energy use* 8.6.5 Scenarios for operational energy use – Module B6
*Guidance*	For existing buildings, if measured historical data consumption are available and applicable (i.e. the objective and the scope of the study are consistent with available data, and future changes in the existing building will not impact on the energy uses), they should be used to calculate the energy demand.Note: the level of detail of energy measurement should allow its use for LCA assessment (i.e. the breakdown of the operational energy demand should be available for each energy carrier). When measured data are available for each energy carrier, building-related and non-building-related uses should be accounted for, as energy monitoring usually does not permit uses to be differentiated. This applies to screening, simplified and complete LCA. For the calculation of energy demand of building-related uses, methods and tools developed by EPA-NR projects may be used.