This European Standard provides a calculation method for the economic issues of heating systems and other systems that are involved in the energy demand and consumption of the building. It applies to all types of new and existing buildings. The fundamental principles and terminology are explained in the standard. The main items of the standard will be: - the definitions and the structure of the types of costs which should be taken into account for the calculation of the economic efficiency of saving options in buildings; - data needed for definition of costs related to systems under consideration; - the calculation method(s); - expression of the result of the economic study. This European Standard is part of the method for calculation of economic performance of energy saving options in buildings (e.g. insulation, better performing generators and distribution systems, efficient lighting, renewable sources, combined heat and power...). The scope of this specific part is to standardize: - the required inputs; - the required outputs; - the calculation formulas; - the type of energy systems concerned with the energy performance of the building. NOTE 1 This is the revision of EN 15459:2007. The revision has been made consistent with the EU regulation on cost-optimal. This revision includes the definition of payback for investment, and inclusion of the costs due to the deconstruction of the building. The method presenting annualized costs has been suppressed. NOTE 2 This standard does not consider financial advantages for higher productivity, higher attractiveness for tenants due to higher indoor comfort, when relevant for comparison of different options. Table 1 shows the relative position of this standard within the set of EPB standards in the context of the modular structure as set out in EN ISO 52000-1. NOTE 3 In CEN ISO/TR 52000-2 the same table can be found, with, for each module, the numbers of the relevant EPB standards and accompanying technical reports that are published or in preparation. NOTE 4 The modules represent EPB standards, although one EPB standard may cover more than one module and one module may be covered by more than one EPB standard, for instance a simplified and a detailed method respectively. See also Clause 2 and Tables A.1 and B.1. (...)