Progress of energy reduction in the Dutch non-profit housing sector
Henk Visscher
OTB-Research for the Built Environment, Faculty of Architecture and the Built Environment, P.O. Box 5043, Delft University of Technology; h.j.visscher@tudelft.nl
Faidra Filippidou
OTB-Research for the Built Environment, Faculty of Architecture and the Built Environment, P.O. Box 5043, Delft University of Technology; f.filippidou@tudelft.nl
Nico Nieboer
OTB-Research for the Built Environment, Faculty of Architecture and the Built Environment, P.O. Box 5043, Delft University of Technology; n.e.t.nieboer@tudelft.nl
Abstract
The European Union formulated high ambitions of energy reductions to be realised in the built environment. The existing housing stock covers a major share of energy use and is seen as high potential to contribute to the savings. This should be realised in the first place by reducing the energy demand for heating by renovation of the existing stock and bring the dwellings to a higher energy performance standard. The targets, policies and programmes are already applied for several years now and the question arises of what progress can be seen in renovation activities and energy saving results. This paper is based on data on improvement rates of the Dutch non-profit housing sector and insight in the relation with actual energy reduction. It shows that the renovation progress is limited and that the actual energy reduction is less than is expected according to theoretical models.
Keywords: Energy efficiency, housing stock, renovation, energy labels, actual energy use Introduction
The residential sector is considered to be responsible for 30 % of the total energy consumption (Itard e.a., 2007, Murphy, 2012). The energy saving potential of the building stock is large and is considered to be the most cost efficient sector to contribute to the CO2 reduction ambitions. Following the Energy Performance of Buildings Directive (EPBD), the European member states aim to improve energy efficiency of dwellings by energy performance regulations for new dwellings and the issuing of Energy Performance Certificates for the existing housing stock. Furthermore it requires strategies to build net zero energy buildings in 2020 and to reach a neutral energy situation in the whole stock by 2050 (Beuken, 2012, Ürge-Vorsatz, 2007).
Besides the energy regulations and policy tools, there have also been made agreements and implementation plans with various stakeholders to make steps towards realising the European and National goals. In the Netherlands these plans are mainly focussing on reducing the energy demand for heating of residential buildings by renovation of the buildings. The overall energy reduction plan in the Netherlands is laid down in the Energy Agreement (SER 2013) which is an agreement signed by many stakeholder organisations with the government. Part of it is a covenant of the Non Profit Housing Organisations, the tenant organisation and the Dutch Government
about the goals of energy reduction in the non-profit housing sector to be released by renovations in 2020. The main goal is to realise an average energy label B for the whole non-profit stock. In this paper we present data that give insight in the current energy performance status of the stock and the improvements that have been made by renovation actions in the recent years. In the second section an introduction to the social housing and the energy efficiency requirements in the country will be presented. The third section goes into detail about the data used and the methods followed. In the fourth section the results will be presented and in the fifth section conclusions will be drawn and steps for future research will be discussed.
Non-profit rented housing and energy efficiency requirements
Housing tenure differs across Europe and no common definition for the non-profit housing sector is used. However, there are three common elements present across European non-profit -social- housing sectors: a mission of general interest, offering affordable housing for the low-income population and the realization of specific targets defined in terms of socio-economic status or the presence of vulnerabilities (Braga e.a., 2013).
In the Netherlands, where the focus of this study lies, the non-profit housing sector counts 2.4 million homes, which is 34% of the total housing market (Aedes 2013, CEDOHAS 2012). This is a unique situation as the Netherlands has the highest percentage of non-profit housing sector in the European Union. The non-profit housing organizations have several goals and criteria to fulfil (Priemus, H, 2013). Energy savings and sustainability seem to be high on the agenda (Aedes, 2013). According to the Energy Saving Covenant for the Rented Sector (“Convenant Energiebesparing Huursector”), the current aim of the social housing sector is to have an average energy label B in 2020. The goal of the agreement represents an energy saving of 33% on the theoretical/predicted energy consumption in the period of 2008 to 2021 (CEDOHAS 2012). Data and methods
In 2008 after the formulation of an earlier covenant on energy saving, Aedes started a monitoring system of the dwellings called SHAERE. SHAERE (“Sociale Huursector Audit en Evaluatie van Resultaten Energiebesparing”) which translates in English as Social Rented Sector Audit and Evaluation of Energy Saving Results, is the official tool for monitoring progress of energy saving measures for the social housing sector. SHAERE is a collective database in which the majority of the housing associations participate. The data imported include physical characteristics and installations of the dwellings in order to be used for their energy labelling. The data include: U and Rc values of the envelope elements, estimated energy consumption, CO2 emissions, the average EI (Energy Index), the registration of the energy label and more. The variables are categorized per property (home). In 2013, 1,448,266 dwellings were available, representing 60% of the total amount of dwellings in the stock.
Research approach
This study presents a first analysis of the trends of the energy renovation pace in the social housing stock in the Netherlands between 2010 and 2013. First, the sample is described and, based on this description, the analysis method is presented. A considerable part of the social housing stock is included in the SHAERE database, but the number of homes differs per year.
Table 1 presents the exact numbers. At the end of each year, since 2010, the housing associations report the state of their dwellings to Aedes.
Table 1: Raw data on the number of dwellings reported in SHAERE per year
Year of reporting Frequency
Percentage of the total stock
2010 1132946 47.2%
2011 1186067 49.4%
2012 1438700 59.9%
2013 1448266 60.3%
In this study the Dutch ‘energy index’ (EI) is calculated through the consecutive years in order to calculate the energy renovation pace based on the energy performance of the dwellings. The energy index is the official tool for measuring the energy efficiency of a dwelling and is then translated to the energy label levels (A to G), where each label level corresponds to an energy index within specified boundaries.
Figure 1 Actual and theoretical gas consumption in Dutch dwellings (Majcen et al., 2013a)
The EI is related to the total theoretical energy consumption of the building, i.e. energy for heating, cooling and ventilation, and lighting of the communal areas (not for individual appliances like TV’s, computers and fridges), under the assumption of a standard use. It is important to keep in mind that the actual energy use differs considerably to this theoretical indicated energy use (Majcen 2013a, b), See figure 2.
According to the norm of the calculation, it is corrected taking into account the floor area of the dwelling and the corresponding heat transmission areas, as shown in Equation 1. A shape correction is applied as well when considering the infiltration losses within space heating demand, while the air permeability coefficient depends on the buildings’ shape factor.
The energy index in the Netherlands is calculated as follows:
𝐸𝐼 = 𝑄𝑡𝑜𝑡𝑎𝑙
155 ∗ 𝐴𝑓𝑙𝑜𝑜𝑟+ 106 ∗ 𝐴𝑙𝑜𝑠𝑠+ 9560
𝑄𝑡𝑜𝑡𝑎𝑙 refers to characteristic yearly primary energy use of a dwelling based on ISSO 82.3 and includes energy for space heating, domestic hot water, additional energy (auxiliary electric energy needed to operate the heating system i.e. pumps and funs),lighting, energy generation by photovoltaic systems and energy generation by combined heat and power systems. 𝐴𝑓𝑙𝑜𝑜𝑟refers to the area of the dwelling whereas 𝐴𝑙𝑜𝑠𝑠 to the areas that are not heated in the dwelling such as a
cellar (Visscher e.a. 2012, Senternovem 2009).
In order to identify the energy improvement in the social housing stock we observed the whole stock for four consecutive years and tracking down the differences in the EI regarding the dwellings that are registered in SHAERE for more than one year. If a deterioration of the energy index over the years was observed, we assume this to be an administrative correction. In these cases the energy index for the years before the change has been corrected to the level of the energy index afterwards.
Results
Figure 2 presents the distribution of the energy labels of the social housing stock for four different years (2010-2013).
Figure 2: Distribution of the energy labels of the non-profit rented housing sector in SHAERE database
It is clear that there is a tendency of an increasing performance through the years. In the first column of the graph, the A label,the A+ and A++ labels are also included. The labels denoting a relatively inefficient home (D, E, F, G) show a decline through the years whereas the ‘higher’ efficiency labels (A, B, C) show an increase. The distribution of the labels corresponds to an average energy index of 1.71 or an average label D for social housing sector in the Netherlands. In 2010 the average energy index was 1.80, in 2011 it was 1.73, in 2012 it was 1.72 and in 2013 it was 1.69 all corresponding to an average label D.
After examining the improvement pace of the stock through the years in the following table the changes of the EI and as a result of the labels are presented. In Table 2, the changes for the period of 2010 to 2013 are presented. 16.8% (258,440 of 1,537,554) had their label improved, moving up from a worse label to a better one (the sum of all dwellings above the diagonal in Table 2), while 83.2% of the pre-labels did not change label category.
Table 2: Number of label changes in each label category (number of dwellings with a pre-label change: n=1.537.554) 2010 A B C D E F G 2013 A 42925 6798 2423 2069 1335 1326 377 B 164595 44294 13012 6617 4269 1551 C 397335 65265 15316 5893 1906 D 342320 38570 14312 2532 E 180030 19163 4738 F 106529 6674 G 45380 Total 42925 171393 444052 422666 241868 151492 63158
The transfer of A labels from the rest of the label categories is: 4% of label B, 1% of label C, 0.5% of label D, 1% of label E, 1% of label F and 1% of label G. However, if we look carefully at the numbers the majority of the dwellings that have moved to label A comes from B, C and D label and not of E, F and G. On the contrary, the majority of the E, F and G labels have moved to D and E labels (17% of E moved to D, 14% of F to E, 8% of G to E and 12% from G to F) as shown on Table 2. The number of dwellings that have undergone major improvements (i.e. from label G, F and E to label A) correspond to 2.2% of the 258.440 dwellings that had their label improved. Additionally, following the changes, another trend is obvious. The majority of
dwellings with a D label in 2010 have improved with a percentage of 16% to label C, whereas the improvement to label B is 3% and to A 0.5%.
Figure 3 presents the size of the improvements in terms of label changes.
Figure 3: Improvement of labels of the non-profit rented housing sector from 2010 to 2013 The largest changes in ‘label steps’ can be observed among the dwellings with a G label. Most improvements, however, are relatively small (one or two steps), which is an indication of the choice of energy efficiency measures applied. The majority of the labels that improved to A label comes from B. This fact also applied to labels from C to B and from D to C respectively.
Conclusions
SHAERE is an extensive database where the state of the social rented sector dwellings’ are reported at the end of each year. This research was based on the dwellings’ physical properties and the reported energy index in order to track the improvements from 2010 to 2013.
For the period of 2010 to 2013, the results show that, although many energy improvements have been realized, they result in small changes of the energy efficiency of the dwellings. If the goal of an average label B by 2021 is to be reached the energy efficiency measures should be strengthened as the average label of the stock in 2013 is D. The majority of the improvements correspond to small changes of the energy index and as a result of the energy label. The number of dwellings that have undergone major improvements (i.e. from label G, F and E to label A) correspond to 2.2% of the 258.440 dwellings that had their label improved. The results show that the efficacy of the measures applied so far is low.
The year by year pace of energy efficiency improvements will provide even more detailed results concerning the energy improvements pace of the Dutch social housing sector. Finally, in future research it is planned to examine which measures are applied in order to assess their efficacy in more detail.
It is important to stress that in combination with the insights of the studies of Majcen (2013 a and b) the minor improvement of the houses in terms of label class steps might even have little relation with a reduction of actual energy use. Realising the goals of the policies seems jet far away.
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