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Application Note: Assessment of Energy Savings

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Assessment of Energy Savings

The purpose of this application note is to define a generic methodology based on practical experience and existing standards to make robust, ex-ante assessments of energy conservation measures (ECM) in buildings. The focus is on the potential energy and cost savings of medium-sized ECMs with a typical incremental investment cost of between €100k and €1 million. Most of the specified methodologies can also be applied to ECMs in other fields, such as at industrial sites. The ex-ante assessment of energy and cost savings is an essential part of the final decision-making process of an ECM investment.


The decision process for potential investment in ECMs should always start with the definition of goals (KPIs). Based on this fundamental first step, potential ECMs or ECM packages can be developed. This application note assumes that these initial steps have already been taken and focuses on evaluating ECMs already specified.


This note provides guidance on how to:

  • collect the relevant input data and boundary conditions
  • determine the most suitable calculation methods for energy and cost savings which can also take into account the uncertainties of the input parameters
  • interpret the results
  • validate and optimize the achievements (measurement concept: what to measure, when and how to do an ex-post assessment)
  • evaluate and minimize the existing uncertainties

This Application Note is part of Leonardo ENERGY's Good Practice Guide, that consists of over 70 application notes, proposing more than 200 good practices in electrical energy. It aims to fill the gap between generalist informative papers and highly technical or academic papers.


Subjects include energy efficiency, renewable energy systems, electrical networks, electricity for buildings, and power quality.