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Energy and Buildings 47 (2012) 285–291

Contents lists available at SciVerse ScienceDirect

Energy and Buildings

j ourna l ho me p age: www.elsev ier .com/ locate /enbui ld

erformance study of DISPLAY database: Trends in municipality buildings

shish Shuklaa,∗, Richard Bullb

Welsh School of Architecture, Cardiff University, Bute Building, King Edward VII Avenue, Cardiff CF10 3NB, UKIESD, De Montfort University, The Gateway, Leicester LE1 9BH, UK

r t i c l e i n f o

rticle history:eceived 15 July 2011eceived in revised form 24 October 2011ccepted 6 December 2011

eywords:nergy certificatesrendsISPLAY

a b s t r a c t

The increasing European Union legislation on building and energy services and widespread adaptationon energy labeling and certification provides a unique opportunity to analyse characteristics of buildingstock at micro and macro level. Thus there is a need to handle large database in order to extract trendsand performance statistics. The European DISPLAY campaign is a voluntary scheme aimed at encouraginglocal authorities to publicly display the energy and environmental performances of their public buildings.The underlying hope is that participating in the DISPLAY certification campaign will lead to significantimprovements in the energy performance of municipal buildings.

This paper addresses the issue of energy certification through presenting trends in building ratings

for energy, CO2 and water. Paper also gives glimpse of trend for performance of buildings using simplemethodology. Encouragingly the clear trend over time is that there has been an increase in the number ofA rated energy certificates, and steady decrease in the number of both F and G rated energy certificates.However, the emphasis of this paper will be on the improvements and deteriorations experienced byspecific buildings. Having assigned a numerical value to each ‘grade’, method has been identified tomeasure the building energy performance.

. Introduction

If national and local governments are serious about tacklingncreasing carbon dioxide (CO2) emissions believed to be con-ributing to our changing climate then sooner or later emissionsrom buildings must be tackled. A building is not just bricks and

ortar, steel and concrete. Buildings are a statement of what weelieve, what we value and how we view the world. Currently, inhe UK for example, buildings constitute 40% of UK carbon emis-ions, with non-domestic stock accounting for roughly half of that.1

ut of the emerging policy agenda – notably the Energy Perfor-ance of Buildings Directive (EPBD) has come a range of solutions

o reduce the energy demand of buildings, new calculation methodsor energy performance, minimum requirements for new builds,nergy audits, boiler inspections and energy certification.

This paper addresses the trends of energy certification through

resenting initial findings from research undertaken by the Insti-ute of Energy and Sustainable Development2 into an Intelligentnergy Europe project by Energy-Cites called Display. The European

∗ Corresponding author. Tel.: +44 0 1244892546.E-mail address: ShuklaA5@cardiff.ac.uk (A. Shukla).

1 According to the Carbon Trust 2008.2 Based at De Montfort University, Leicester, UK.

378-7788/$ – see front matter © 2011 Elsevier B.V. All rights reserved.oi:10.1016/j.enbuild.2011.12.002

© 2011 Elsevier B.V. All rights reserved.

DISPLAY campaign is a voluntary scheme, started by Energy-Cities,3

aimed at encouraging local authorities to publicly display theenergy and environmental performances of their public buildings.This paper has policy relevance in that it considers the role of EnergyPerformance Certificates and their trends in EU Member States. Ithas academic relevance too as recent research by Dascalaki et al.[1] has shown; there is a scarcity of information around the perfor-mance of European municipal buildings. Present paper will alsoexplore further research questions regarding building stock andtheir performance.

2. Policy and literature background

Europe’s buildings remain a large energy consumer compris-ing 40% of final energy use and 36% of EU CO2 emissions [2–4].But on average, water usages and space heating are responsi-ble for more than 60% of the final energy consumption in bothdomestic and non-domestic building stock [5]. During the past

few decades governments in various countries have initiated poli-cies to reduce energy consumption in buildings. Most of thepolicies lie in the main three categories: economic incentives,informational programs and regulatory requirements. Economic

3 Energy Cities is a European network of municipalities created in 1990 and nowrepresenting over 1000 towns and cities across 26 countries.

2 nd Bu

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86 A. Shukla, R. Bull / Energy a

ncentives include taxes and energy pricing; informal programsnclude energy awareness campaigns and energy audits; regula-ory requirements include codes or standards. Often policy studiesook either in favor or against regulatory and economic instrumentsn terms of detailed study of their effectiveness [6,7]. Commu-ication perspective is often the most popular in the theory ofiffusion of innovation [8]. Different policy studies had differentiew, some researchers think communication instruments can beseful when it comes to address problems related to information.owever for example just consider energy labels for appliances areeing used as a communicative instrument in order to establish aarket demand, and environmental awareness. Most EU countries

ave legislation at the national level although there may be addi-ional local laws as well. The high dependence on energy suppliedutside from EU member countries [9] and increase in greenhouseas emissions led EU Member States to draw up a common energyolicy. For member states of the EU, legislation is being driven by EU

aws, e.g. Energy Performance of Buildings Directive (EPBD), hav-ng freedom of local implementation of building codes. Nationalegulations have to follow the concept of the EPBD and need bearmonized as much as possible [10].

Diverse standards and labeling schemes exist around the worlduch as R2000 (Canada),4 LEED (USA),5 MINERGIE (Switzerland),6

REEAM (UK)7 and many others. The energy standards for build-ngs in various countries are in different stages, e.g. mandatory,oluntary, and proposed for different building sectors. Janda [11]ade a survey of these standards for 80 countries worldwide.

hey reported that 59 countries have some form of mandatoryr voluntary existing standard, twelve countries had proposedtandards and nine countries did not have standards (Fig. 1). Infor-al programs deals with awareness and user engagement for the

eduction in energy demand. Various energy initiatives aim toupport the work of actors working at local and regional level.anagEnergy,8 Sustainable Energy Europe campaign,9 Europeanreenlight programme10 EU Energy Star programme,11 Associa-

ion for the Conservation of Energy,12 Energie Cities,13 Europeanustainable Energy Education Forum (ESEEF),14 Kids for Energy15,K Centre for Sustainable Energy,16 Alliance to Save Energy17 andisplay-campaign18 are various energy initiatives programs goingn at local level or EU level. The European Display Campaign is a vol-ntary scheme designed by energy experts from European townsnd cities. As most of member states have a national certificate forheir exiting public buildings, Display is increasingly being used as

complementary communication tool. In order to sense clearly thetory our buildings are saying about us we need to be able to listennd understand with accurate hearing. This paper explores whatuildings are saying by analysing information gained as a result ofhe Energy-Cities project: the DISPLAY campaign.

4 http://www.minergie.com/home en.html.5 http://www.breeam.org/.6 http://www.managenergy.net/.7 http://www.sustenergy.org/.8 http://www.managenergy.net/.9 http://www.sustenergy.org/.

10 http://www.eu-greenlight.org/.11 http://www.eu-energystar.org/en/.12 http://www.ukace.org/pubs/reports.htm.13 http://www.energie-cites.org/.14 http://www.school4energy.net/.15 http://www.kids4energy.net/.16 http://www.cse.org.uk/.17 http://www.ase.org/greenschools/.18 http://www.display-campaign.org/.

ildings 47 (2012) 285–291

2.1. The DISPLAY Campaign

With increasing European Union legislation on buildings andenergy services, and the widespread adoption of energy labels forelectrical appliances, there is a need for municipalities to demon-strate commitment to energy efficiency by displaying an energylabel on their buildings. Energy Performance Certificates (EPC’s) area key aspect of the ‘Energy Performance Buildings Directive (EPBD)approved on 16 December 2002 and brought into force on 4 January2003 [12]. The principal objective of the Directive was to promotethe improvement of the energy performance of buildings withinthe EU through cost-effective measures. Relating to EPC’s the direc-tive stated there must be an energy performance certificate madeavailable whenever buildings are constructed, sold or rented out.

Implementation was subsequently much harder than firstrealised. Lack of implementation across Europe and confusinginterpretations led to the proposed ‘recast’ which was finally agreedin November 2009 and sets ambitious targets for the future of publicbuildings. The initial EPBD left widespread confusion over what wasrequired across European with regards to EPC’s. England and Walesbeing the only nation to adopt a national directive that requiredall public buildings over 1000 m2 to produce EPCs. The recast wasfinally published in June 2010 in the official journal of the Euro-pean Union.19 As of 31 December 2020 new buildings in the EUmust consume ‘nearly zero’ energy and the energy will be ‘to avery large extent’ from renewable sources. The recast also calls fora more detailed and rigorous procedure for issuing energy perfor-mance certificates in member states including reducing the size ofbuildings required to produce them. EPCs will have to be producedfor all public buildings over 500 m2, and then from 2015, buildingsover 250 m2.20

The Display Campaign is a voluntary scheme municipalities canadopt to demonstrate a commitment to reducing energy consump-tion of public buildings. The label is similar to that already acceptedon European Union electrical appliances. The rating is from A–Gwith A being most efficient, or preferred. Buildings are rated accord-ing to primary energy consumption, greenhouse gas emissions(mainly Carbon Dioxide) and water consumption. A key part of therationale for developing the energy display label was to motivatedecision makers towards a common approach for European certi-fication for energy performance of non-residential buildings, andengage municipal energy managers and the general public aroundthe subject of energy and buildings. Energy-Cities has produceda number of promotional tools including leaflets, a website and acommunication handbook. These are available in 16 languages. Itswebsite provides opportunity for the public to access informationabout the project. It also has a restricted domain where Energy Citesmembers can access their display data and generate posters. It per-forms three functions: a calculation tool, a monitoring and benchmarking tool, and a tool to encourage dialogue between decisionmakers, municipal experts and the general public.

3. Summary of DISPLAY database

DISPLAY database includes various parameters covering impor-tant range of building characteristics (Fig. 2). The data refers toenergy certificate data (Energy, CO2 and water certificates), gen-eral building data (location, year of certificate, end use, hour in use,

surface area and facilities) and annual summary of consumptiondata (gas, fuel, wood, coal, electricity, co-generation, district heat-ing, thermal, solar and water consumption). The data is supplied

19 http://eur-lex.europa.eu/JOHtml.do?uri=OJ:L:2010:153:SOM:EN:HTML.20 DIRECTIVE 2010/31/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL

of 19 May 2010 on the energy performance of buildings (recast).

A. Shukla, R. Bull / Energy and Buildings 47 (2012) 285–291 287

Fig. 1. Worldwide status of energy

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Fig. 2. Main Structure of DISPLAY database.

n .csv format and further analysed using SQL server database andXCEL worksheets. The database is populated with data from reg-stered DISPLAY user buildings by the 28 participating Europeanations from 2001 to 2009 for a total of 11,586 buildings.

To date over 25,80021 energy-rating certificates for differentypes of dwellings were issued (Fig. 3). Countries such as France andreat Britain have issued the majority of certificates, with Czechepublic, Ukraine and Finland following close behind.

Sixteen different types of buildings are registered for DISPLAYampaign. Maximum numbers of certificates are produced for gen-ral school buildings followed by meeting place and administrativeuilding (Fig. 3b).

21 Using data downloaded from the Energie-Cites website on May 20th 2010.

standards for buildings [11].

3.1. Emerging trends in municipal buildings

Trends in municipality buildings are studied under two heads;trends for energy ratings and trends for building performance.Trends for building performance usage simple method of move-ment calculation and average score in different countries forenergy, CO2 and water DISPLAY certificates.

3.2. Trends in energy ratings

To gain a more meaningful picture of what has happened overrecent years we need to consider the trend over time in 28 partici-pating European nations (Figs. 4-6).

Encouragingly the clear trend is that there has been an increasein the number of A rating energy certificates issued, and a steadydecrease in the number of both F and G rating energy certificates.In fact the result shows an increase in the number of energy certifi-cates issued relating to the energy rating of A, B, C and D. However,the number of A certificates being issued is still a low percentageof the total number, the majority of certificates issued are C and D(Fig. 4). While the trend for G ratings is decreasing, the number ofG certificates being issued is still high (Table 1a). For energy rat-ing maximum increase (approx 10% increase) observed for C ratingcertificates during 2001–2009 (Table 1a).

Continuous increase in A certificates for CO2 during 2001–2008

while there is downward trend observed in 2009 (Fig. 5). Thedecrease in G certificates for CO2 is not as significant as observed forenergy certificates (Table 1a and Table 1b). The percentage share ofA certificates has continuously increased for water (Fig. 6) though

288 A. Shukla, R. Bull / Energy and Buildings 47 (2012) 285–291

Table 1aEnergy DISPLAY certificates issued for different ratings (A–G) during 2001–2009.

Ratings Year

2001 (%) 2002 (%) 2003 (%) 2004 (%) 2005 (%) 2006 (%) 2007 (%) 2008 (%) 2009 (%)

A 00.99 00.74 01.69 02.73 03.69 03.60 04.21 04.77 03.25B 10.34 06.32 07.66 08.92 09.83 09.49 12.55 14.25 14.29C 17.24 14.50 19.70 17.85 18.92 19.85 24.42 25.77 25.56D 21.18 28.25 20.68 21.63 21.23 23.34 24.43 21.80 22.98E 14.29 14.87 19.16 18.24 17.08 17.69 14.85 13.84 12.95F 14.78 17.10 12.48 12.31 11.47 10.80 08.28 07.55 08.89G 21.18 18.22 18.63 18.32 17.78 15.23 11.26 12.02 12.09

Table 1bCO2 DISPLAY certificates issued for different ratings (A–G) during 2001–2009.

Ratings Year

2001 (%) 2002 (%) 2003 (%) 2004 (%) 2005 (%) 2006 (%) 2007 (%) 2008 (%) 2009 (%)

A 02.46 04.46 05.88 06.55 09.67 08.57 11.49 13.14 09.56B 07.88 07.43 13.73 13.09 15.76 14.55 18.74 19.32 17.44C 19.21 21.19 27.36 21.01 22.11 22.56 25.64 24.83 24.94D 26.11 26.39 21.75 17.42 17.96 20.16 18.64 18.36 17.92E 11.33 17.10 12.83 15.24 12.49 13.33 11.09 09.78 11.61F 15.27 09.29 06.68 09.20 07.86 08.05 05.81 05.61 06.59G 17.73 14.13 11.76 17.50 14.14 12.78 08.58 08.96 11.94

Table 1cWater DISPLAY certificates issued for different ratings (A–G) during 2001–2009.

Ratings Year

2001 (%) 2002 (%) 2003 (%) 2004 (%) 2005 (%) 2006 (%) 2007 (%) 2008 (%) 2009 (%)

A 10.34 08.55 08.82 10.64 11.03 12.19 13.94 13.68 23.84B 14.78 14.50 15.51 13.41 15.23 16.05 15.32 18.47 19.21C 16.26 18.22 22.10 16.56 16.67 18.52 17.06 17.38 16.58D 12.81 19.33 15.51 15.82 15.07 14.20 14.21 13.11 11.71

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E 12.32 10.04 09.71 11.85

F 09.36 10.78 06.60 08.46

G 24.14 18.59 21.75 23.27

emonstrating higher share of G ratings which has been decreaseduring 2001–2009 (Table 1c).

How the DISPLAY certificates are produced during 2001–2009n major participation countries (countries issued more than 1000ISPLAY certificates) are shown in Fig. 7. It has been seen that coun-

ries having more participation in early years experiencing decreasen recent years, this may be because of introduction of new policiesr programs at National/regional level. For example in case of GBarbon reduction commitment (CRC), Display Energy CertificatesDEC) greatly affected the staff time availability in municipalityuilding to further engage in this voluntary CYBER DIPLAY project.ut for countries like Ukraine (UA) who started participation after004, the numbers of certificates issued are increasing graduallyvery year.

.3. Building performance analysis

.3.1. MethodologyCentral to our analysis is whether or not buildings have

mproved their performance as a result of their involvement inhe DISPLAY campaign. The hope of the campaign has always beenhat as a result of displaying the DISPLAY certificate, and throughndertaking communication with building users, that buildingerformance improves and energy consumption decreases. Thisuestion will be addressed through research into building users

s a result of this initial analysis. First we need to identify buildingshich had changed their performance so they can be researched.

he aim is to identify, which buildings have either improved theirnergy ratings or actually deteriorated during the course of the

10.36 10.36 10.58 10.47 08.2207.67 07.85 07.34 07.34 05.4523.97 20.85 21.55 19.54 15.00

DISPLAY program. For this analysis a methodology has been devel-oped to assess the changes that have occurred during the course ofthe campaign. Each building’s energy rating certificates will be usedto establish its progress. This is a move from analysis of certificatesto an analysis of individual buildings.

A method has been identified that would enable this analysis.The method is based on a comparison between the earliest andlatest certificates issued for buildings. To do this a core metric couldbe designed to represent the effectiveness of efforts to improvebuilding energy performance, based on the progression of displayenergy ratings for a given building over time. In order to capturethe overall success irrespective of when changes were made, themetric would be based on the entire period of available data. Ratingare provided between A to G, where A is highest possible ratingachieved by the building and G lowest. Ratings given a numericalvalue in ascending order with incremental value of 1 starting fromlowest building rating (G). Numeric value of different ratings canbe found in Table 2. Movement � in ratings can be written as:

� = (Latest rating − Earliest rating) (1)

if the earliest certificate is of higher rating e.g. “A” (numericvalue 7) in year 2001 and latest rating is in year 2008 and is “E”(numeric value 3). The movement in rating calculated will be −4(Latest–Earliest) and if the case is vice versa it will be +4. Negativemovement in rating implies deterioration over time however pos-

itive movement implies improvement in the performance of thebuilding.

This metric highlights changes in building energy certificate rat-ings. The maximum movement, from “G” to “A” or from “A” to “G”,

A. Shukla, R. Bull / Energy and Buildings 47 (2012) 285–291 289

Table 2Assigned numeric value of DISPLAY certificates ratings.

Ratings A B C D E F G

Numeric value 7 6 5 4 3 2 1

Fig. 3. (a) Number of certificates issued in different countries (countries having lessthan 100 certificates are excluded). (b) Percentage of different types of buildingsi

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Fig. 5. The graph shows the percentage of CO2 rating certificates issued from 2001to 2009 for each rating.

fore it is possible to take the first and latest certificate rating andconduct an analysis.

The movement histogram for energy, CO2 and water rating isgenerated using Eq. (1) (Fig. 8). Buildings showing zero movement

nvolved in certification.

s equivalent to +6 and −6 respectively. As expected this is quiteare within the database. Smaller movements are more commonnd the most common scenario is that a building retains the sameating for all issued certificates (a movement of zero). Buildingsaving only one certificate are excluded from the analysis of afore-aid method and this limits the number of participating countries

o 21 from 28.

ig. 4. The graph shows the Energy rating certificates issued from 2001 to 2009 forach rating.

Fig. 6. The graph shows the water rating certificates issued from 2001 to 2009 foreach rating.

3.3.2. Trends in building performanceFor the purposes of this paper is it helps us to see the overall

trajectory of a building over time since 2001–2009. The main rea-son for using above-mentioned method (earliest and latest ratingsconsidered for analysis) is that this provides updated informationwith respect to change occurred in performance of building. There-

Fig. 7. Number of certificates issued in major participating countries during 2001to 2009.

290 A. Shukla, R. Bull / Energy and Buildings 47 (2012) 285–291

Table 3Chart detailing overall improvements of buildings.

Country Total score Building count Average score

Energy CO2 Water Energy CO2 Water

Poland 45 55 1 21 2.143 2.619 0.048Croatia 14 15 −9 19 0.737 0.789 −0.474Ukraine 394 446 368 696 0.566 0.641 0.529Hungary 5 7 −1 9 0.556 0.778 −0.111Great Britain 548 751 39 1026 0.534 0.732 0.038Germany 34 −20 2 86 0.395 −0.233 0.023Slovenia 9 11 1 34 0.265 0.324 0.029Lithuania 4 −3 −1 17 0.235 −0.176 −0.059Slovak Republic 17 14 17 74 0.230 0.189 0.230Greece 1 3 −3 5 0.200 0.600 −0.600Bulgaria 17 13 −13 114 0.149 0.114 −0.114Spain 3 1 5 21 0.143 0.048 0.238Netherland 2 5 −13 18 0.111 0.278 −0.722France 225 353 565 2219 0.101 0.159 0.255Belgium 10 22 8 101 0.099 0.218 0.079Romania 1 6 −3 14 0.071 0.429 −0.214Italy 5 5 40 104 0.048 0.048 0.385Switzerland −2 3 174 786 −0.003 0.004 0.221Finland −10 20 12 202 −0.050 0.099 0.059Ireland −5 −9 −6 13 −0.385 −0.692 −0.462Portugal −7 −4 2 4 −1.750 −1.000 0.500

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ustria, Denmark, Estonia, Luxembourg, Sweden, Czech Republic and Malta, each

ollected and so do not appear in the table.

re those building which have not changed their rating during001–2009, whereas building with positive movements are build-

ngs which improved their performance in due course of time andice versa. There might be various factors involved in improvinguilding performance, e.g. user engagement, energy awareness,p gradation of building fabric, insulation, efficient lighting andany others. These measures could vary from country to country

nd building to building. The building which had improved theirnergy and CO2 ratings are almost same (33% of total), as it is clearO2 emissions are proportional to energy consumption if energy

s not produced by renewable. In case of performance of watersages performance it has been found that improvement in watersages performance is occurred only in 29% of buildings. The build-

ngs which deteriorated in due course of time are approximately6%, 14% and 20% respectively for energy, CO2 and water perfor-ance. Almost 50% of buildings haven’t undergone in any change

nd stayed neutral in terms of their performance. It is quite clear

Fig. 8) that shift is towards improvement in buildings with com-arison to deterioration. This analysis can lead us to identify whichountries have seen an increase in their building stock performancend those that have not (Fig. 8).

ig. 8. The figure shows the movement histogram of buildings with their relevantnergy performance.

o buildings which had issued more than one certificate at the time the data were

The average movement score for different country for Energy,CO2 and water ratings are also calculated (Table 3) by using:

Average score =j∑

i=n

(�

n

)(2)

where i represents number of buildings in a country and j repre-sents respective country. Buildings with only one rating certificateduring 2001–2009 are excluded while calculating the averagescore. Poland leads the tally for improvement in ratings for energyand CO2 where as far behind if we talk about performance of waterratings. It is quite clear that countries having high (improvements)for energy have the same for CO2 but not for water, this is a furtherpoint of consideration when making detailed study based on surveyresults. The countries having fewer number of buildings registeredare found to perform quite well with comparison to countrieswith a greater number of registered buildings–is this because ofmotivation, government policy, or effective showcase for DISPLAYcampaign and engagement of occupiers for improvement of build-ing performance – future building research will hopefully shed lighton this.

3.4. Conclusions

This paper has laid out the current picture of DISPLAY certificatesacross Europe. These figures are a very useful guide to help pick outareas of interest. Deterioration in energy ratings may have causeswhich are uncontrollable. However, the scores do provide an indi-cation that conditions are more favorable in some countries than inothers. For now it is clear that the patterns of building energy con-sumption are changing, for the better. Poland having high averagescore for energy (2.143) whereas Portugal (−1.750) had least; thetrend for the average score of CO2 rating is also same. It is hopedthat as part of the next stage of our research there will be moreanswers to questions, and no doubt, more questions.

Acknowledgements

The authors gratefully acknowledge the support of IntelligentEnergy Europe in funding the Cyber Display Research project, the

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CamS

R

[

[11] K.B. Janda, Worldwide status of energy standards for buildings. A 2007 update,

A. Shukla, R. Bull / Energy a

yber Display Project team – Peter Schilken and Ian Turner as wells members of the consortium who supplied details of their engage-ent activities. Finally, thanks go to all at the IESD, and Helen

antiago and the Ecobuild team.

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