1. SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Central Europe experience and knowledge about sustainable rehabilitation of housings and energy management 1.Social background and expectations 2.Overview about reached rehabilitation status 3.Expected transitions (shifts)

2. SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte 1.Social background and expectations -europe-wide the operation of buildings count for round about 40% of the final energy consumption -in Germany round about 30% of the final energy consumption is related to housing -round about 80% of this energy is needed for heating (warm water, cooking, ligthning, and so on is the rest)

3. SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Generally mind-set of dweller concerning rehabilitation [1]: good very good Ex ante in between ex post retrospective questioning

4. SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Generally mind-set of dweller concerning rehabilitation [1]: Advantages: ? Disadvantages/Burden: -construction site dirt -site noise -constriction in using the rooms -untidiness -enduring presence of craftsman -insufficient information about coordination, kind and amount of rehabilitation workflow

5. 5 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Expectations of dwellers [1]: Improvement of the residential building very importantnot important at all CO 2 reduction Increasement of comfort of living energy saving Improvement of the building climate Reduction of heating costs

6. 6 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Age structure of buildings respectively flats [2]: buildings flats

7. 7 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Ownership conditions [2]: buildingsdwellings All buildings% Private ownership88.362.4 Community of owners5.515.6 Housing company5.520.7 others0.71.2 One and two family houses private95.995.2 Community of owners2.83.5 Housing company0.8 Multi family houses private50.933.0 Community of owners18.526.5 Housing company28.738.7

8. 8 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Building size and floor numbers [2]: One and two family housesShare of buildings in % One dwelling 73.0 Two dwellings 27.0 One floor 39.2 Two floors 55.7 More then two floors5.1 Multi family houses 3 – 4 dwellings53.7 5 – 6 dwellings18.6 7 – 12 dwellings19.0 More then 12 dwellings8.8 1 – 2 floors41.3 3 – 4 floors51.1 5 – 9 floors7.3 More then 9 floors0.3

9. 9 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Heat insulation status [2]: Buildings (%) with insulation of Exterior wallsRoof / upper floor ceiling Basement ceiling / ground floor All buildings42.176.437.1 Old buildings constructed before 1978 35.768.223.3 Year of construction 1979 - 2004 53.292.162.1 New buildings constructed after 2005 66.098.587.3

10. 10 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Heat insulation status [2]: ex post insulation Buildings (%) with insulation of Exterior wallsRoof / upper floor ceiling Basement ceiling / ground floor All buildings42.176.437.1 Old buildings constructed before 1978 35.768.223.3 Year of construction 1979 - 2004 53.292.162.1 New buildings constructed after 2005 66.098.587.3 Buildings (%) with ex post insulation of Exterior wallsRoof / upper floor ceiling Basement ceiling / ground floor All buildings20.840.59.5 Old buildings constructed before 1978 27.652.212.5

11. 11 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Ex post insulation of multi family houses constructed before 1978 [2]: geographical differences Multi family houses (%) with with es post insulation of Exterior wallsRoof / upper floor ceiling Basement ceiling / ground floor Northern parts of Germany22.542.46.8 Southern parts of Germany21.243.08.7 Formerly GDR39.564.922.3

12. 12 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Exterior walls: kind of wall construction in % [2] Kind of wall constructionwhole Germanynorthsoutheast brick, one layer61.332.485.163.4 brick, two layers29.961.26.521.5 truss wall3.12.42.94.9 timber frame construction3.73.34.33.2 concrete, prefabricated elements1.90.71.06.7 Kind of wall constructionbefore 19781979 - 20042005 until now brick, one layer63.856.057.5 brick, two layers28.732.827.8 truss wall4.40.40.6 timber frame construction1.57.513.0 concrete, prefabricated elements1.53.10.8

13. 13 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Insulation thickness (exterior walls) [2]: Insulation thickness percentage All Old buildings before 1978 Between 1979 and 2004 New buildings after 2004

14. 14 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Insulation thickness (exterior wall, old buildings before 1978) [2]: Insulation thickness percentage All old buildings Constructed with insulation Ex post insulation

15. 15 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Insulation thickness (exterior wall, old buildings before 1978) [2]: Insulation thickness percentage Brick, one layer Brick, two layers Truss wall Prefabricated concrete elements

16. 16 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Thickness of upper floor ceiling / roof insulation[2]: Insulation thickness percentage All housing buildings Old buildings before 1978 Buildings from 1979 – 2004 New buildings from 2005 to now

17. 17 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Ex post insulation thickness of roof / upper floor ceiling (old buildings before 1978) [2]: Insulation thickness percentage Roof not heated Roof heated

18. 18 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Insulation thickness of ground floor / basement ceiling [2]: Insulation thickness percentage All housing buildings Old buildings before 1978 Buildings from 1979 – 2004 New buildings from 2005 to now

19. 19 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Height of the basement [2] (old buildings before 1978): Heating situation in the basement [2] (old buildings before 1978): percentage High basement (a person 1.80 m tall can use it erectly)75.9 Low basement (a person 1.80 m tall can use it barely)19.3 Very low basement (a person 1,80 m tall have to crouch down)4.8 Percentage No basement12.6 Not heated basement61.9 Partly heated basement22.2 Completely heated basement3.3

20. 20 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Frequency distribution of window age [2]: Installation age percentage All buildings Old buildings before 1979

21. 21 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Thermal insulation glass production in Germany [2]: Triple glazing (U=0.7 W/m 2 K) Duplex glazing (U=1.1 W/m 2 K) Duplex glazing (U=1.2 W/m 2 K) Duplex glazing (U=1.4 W/m 2 K)

22. 22 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Kind of glazing and window installation year [2]: All buildingsOld buildings before 1978 New buildings from 2005 until now Windows installed before 1994 Single glazing2.24.1 Douplex glazing41.256.8 Trippel glazing0.50.4 Windows installed after 1995 Single glazing0.30.20.3 Douplex glazing52.636.485.0 Tripel glazing3.22.014.7 sum100

23. 23 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Kind of heating and energy source [2]: Old buildings before 1978 Buildings from 1979 until 2004 New buildings after 2004 Kind of heating district heating3.94.03.6 central heating79.992.492.2 seperate dwelling heating6.31.51.6 individual room heating9.92.12.5 Kind of energy source district heating3.94.03.6 gas47.959.860.1 oil37.229.45.9 biomass6.52.69.2 coal1.00.0 electricity3.54.321.1

24. 24 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Amount of modernisation (year of construction before 2004) [2]: Number of energy saving measuresPercentage Only one energy saving measure66.4 Two energy saving measures20.9 Three energy saving measures6.4 Four energy saving measures4.2 Five energy saving measures1.9 Six energy saving measures0.3 100

25. 25 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Amount of energetically rehabilitation intentions during the next five years [2]: IntentionAll buildingsOld buildings before 1978 Exterior wall insulation7.59.6 Roof or upper floor ceiling insulation8.511.0 Basement ceiling or ground floor insulation3.75.0 Installation of new windows7.59.5 Installation of photovoltaic elements2.51.9 Installation of solar heating elements4.74.3 Installation of district heating connection0.1 Replacement of the heating system10.210.4

26. 26 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte 3.Expected Transitions Thinking about energy demand or energy consumption calculation in a different way as it is done today -by establishing such calculations as a sustainability criteria, -integrating user/owner behaviour an consider this as an important aspect, -combining energy calculation with economical calculations (costs, value, finance) and -establishing new policy instruments if they are more effective.

27. 27 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte In Germany nowadays used energy certificate:

28. 28 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte But, what's the real situation (1)? Calculated energy demand in kWh/(m 2 a) Measured energy consumption in kWh/(m 2 a)

29. 29 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte But, what's the real situation (2)? Low energy housing district Niedernhausen Measured energy consumption per m² in 1994 heating energy average

30. 30 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte European and German climate protection and energy saving goals - goals 2020 (European council, March 2007) - 20 % reduction in green house gases compared to 2005 - 20 % share of renewable energy - 20 % reduction of the energy consumption - goals of the German government until 2050 (German energy concept 2011) - 80 % reduction of green house gases - 50 % reduction of the primary energy consumption - 25 % reduction of the electrical power consumption (wattage, end energy) - 40 % reduction of the traffic related energy consumption - 80 % reduction of the head demand of buildings - 60 % share of renewable energy of the energy consumption (end energy) - 80 % share of renewable energy of the the electrical power consumption (gross value)

31. 31 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Some statistical data (Germany 2009, Federal Ministry of Economics and Technology): First orientation: Total primary energy consumption: 13,300 PJ/year = 163 GJ/(capita·year) = 5,170 W/capita Head energy consumption (private households): 2,300 PJ/year = 28 GJ/(capita·year) = 900 W/capita Can you imagine 900 W?

32. 32 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Architects and engineers are not so familiar with this 900 W/inhabitant Their key number is something in kWh/(m 2 ∙year): Total amount of head floor space (only residential buildings): 34.85 Gm 2 This lead to annually: 2,300 PJ/34.85 Gm 2 = 660 MJ/m 2 or with 365∙24∙3600 = 31,536,000 seconds per year to 660 MJ/(m 2 ∙31,536,000s) = 20.9 W/m 2. One year is equal to 8,760 h so that there is an average head energy consumption of: 20.9 W/m 2 ∙8,760 h/year = 183,084 W∙h/(m 2 ·year) = 183 kWh/(m 2 ·year).

33. 33 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte German Goal: 80 % reduction Target value for 2050: average head energy consumption: 0.2∙183 kWh/(m 2 ∙year) = 36.6 kWh/(m 2 ∙year) or: 0.2∙900 W/inhabitant = 180 W/inhabitant (reachable or hallucination?)

34. 34 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte Influence of rehabilitation done in the past on energy consumption (Berlin buildings) precast concrete slabs and district heating brick buildings and heating with gas or oil Energy consumption in kWh/(m 2 a) before rehabilitation after rehabilitation (average) best value

35. 35 SuReReEnMaHo - Central Europe experience and knowledge Prof. Dr.-Ing. Dieter Bunte References: [1]Institut Wohnen und Umwelt: Akzeptanz energetischer Maßnahmen im Rahmen der nachhaltigen Modernisierung des Wohnungsbestandes, Forschungsbericht, Darmstadt, 2006. [2]N. Diefenbach, H. Cischinsky, M. Rodenfels, K.D. Clausnitzer: Datenbasis Gebäudebestand, Forschungsbericht, Darmstadt, 2010