1 IntroductionIn the year 1979, the first World Climate Conference took place and this led to the setting up of the Intergovernmental Panel on Climate Change (IPCC) in 1988. This was followed by the creation of Kyoto protocol in 1997. As a result of the Kyoto protocol and IPCC reports, the EU produced a European directive: 2002/91/EC Energy Performance of Buildings. Further, the EU directive led to a spate of legislation across Europe, as the main requirement, which was to produce Energy Performance Certificates (EPCs) for dwellings and non-dwellings1. Hence, the Energy Performance Certifications were introduced for the first time in the framework of European legislation in 20022. The EPBD requires buildings to have an energy performance certificate (EPC), or energy label, when sold or rented. The aim of this energy label is to show (potential) homeowners the energy efficiency of their dwelling in a simple way. Apart from this, the labelling system is used by policy-makers to set energy-saving targets and develop policies. All member states had implemented the directive by the end of 2009, some more effectively than others (**). This process seems to have been well studied within numerous EU projects and initiatives(**).In a few member states (i.e. the Netherlands, Denmark, and some regions of Austria), systems which were similar to Energy Performance Certifications were being operated before the implementation of the EPBD. Nevertheless, the mechanism was still new for many countries and needed to be designed from the scratch. When the EPBD recast (2010/31/EU) was introduced in 2010, 8 out of 28 countries still had not implemented EPCs for all types of buildings 6, see Fig. 2-1. Till date, all the 28 Member States have formally been able to implement the EPBD requirements for EPCs in their national legislation; only a few minor changes are still expected: In Hungary where the voluntary EPCs for leased buildings will be replaced by mandatory ones in 2015, and In Slovakia the mandatory certification of building came into force in 2016. According to the EU project IMPLEMENT (Campaigning for the future, 2010), two major reasons for the differences in the success of the implementation among different member states are the looseness of the regulations in the directive, which leave ample room for interpretation, and the fact that no sanctions are imposed in cases where the rules of the EPBD are ignored. Additionally, this report/project was specifically designed to investigate why EPCs aren’t effective enough in motivating homeowners to adopt low-carbon measures (Majcen et al,. 2013). The outcome results were used for several policy instruments to improve the impact of the EPBD. However, all these projects deal with implementation of the EPBD strategically and overlook the accuracy and outcomes of the calculation methods used. Among the member states, different methodologies of the calculation of EPC are used due to the fact that the methodology is not defined well by the EPBD. As a result, the member states developed very different approaches and methodologies. The Dutch energy performance measurement system, based on the ‘Decree on Energy performance of buildings (BEG) and the ‘regulation on energy performance of buildings’ (BEG) was introduced in 2008. The determination of the EPC is explained in the NEN 7120 Energy Performance of Buildings (EPG) standard. The calculation of the EPC is done on the basis of the building characteristics, installations and standard use behaviour. This standard applies to new constructions of dwellings and non-dwellings. However, since the exact building specifications of existing dwellings are not known, a different method to express the energy efficiency was needed. For the existing stock, a different measure, named the energy index (EI) is implemented and indicates the energy efficiency in a number as well, ranging from 0,5 very good to 2.9 extremely bad performance. The EI is calculated on the basis of the total primary energy demand, the calculation method is described in NEN 7120 as well. Based on the EI an energy label is assigned to the label, ranging from A to G. The difference between the two systems lies in the outcome results, however the method of the calculation is almost the same. The primary goal of this energy label is to provide homeowners with information on the thermal quality of their dwellings. To increase the practical significance of the label, the expected energy usage of the dwelling is also mentioned on all Dutch labels issued after January 2010 (*reference Majcen). In addition, the label contains recommendations for possible energy-saving measures for the type of housing concerned. These recommendations also include indicative costs, benefits and returns per housing type. According to the RVO (Rijksdienst voor Ondernemend Nederland), the suggested measures contribute to a comfortable and energy-efficient home. According to the outcome of a survey conducted by IDEAL (2010), homeowners use the recommendations as a reference on what kind of measures could improve the energy efficiency. In general, people would appreciate information about the cost of adopting low-carbon measures and where to find further advice, such as specialised professionals or a public body. This stresses the need for the EPC to provide the information homeowners are interested in to be effective. What kind of information the EPC provides is not the only important aspect, but also how it is presented. According to the findings, homeowners do not necessarily make a strict distinction between energy-related renovations and other ones. Instead of thinking about energy, people actually care about how to reach more comfort in their dwelling. Therefore, the EPC could link up those issues that are meaningful to people and that they are concerned with.