The changing role of life cycle phases, subsystems and materials in the LCA of low energy buildings Gian Andrea Blengini a,b, *, Tiziana Di Carlo c a DISPEA - Department of Production Systems and Business Economics, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy b CNR-IGAG: Institute of Environmental Geology and Geo-Engineering, Corso Duca degli Abruzzi 24, 10129 Turin, Italy c DICAS - Department of Housing and City, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy 1. Introduction Lowe ring ener gy intensity and environment al impacts ofbuilding s is inc reasingly bec oming a pri ori ty in ene rgy and envir onmental pol ici es in Eur ope an cou ntr ies. In Italy, suc h poli cies are being integ rated in ener gy strat egies and building regulatio ns at different scales, from nati onal to local, mainly through direct and indirect actions that are aimed at decreasing energy requirements during the use phase, with focus on winter heating. Although it is reasonable to tackle priorities for improving the environmental sustainability of buildings starting from the most energy intensive elements, it should be pointed out that not only is the use phase a source of environmental concern, but also the whole life cycle. The overall environmental impacts ofbuildings extend beyond the use phase, as they also encompass the embodied energy and environmental burdens related to resource extraction and manufacturing, construction activities, as well as dismantling and construction waste disposal at end- of-life (EOL). Moreover, life cycle impacts are highly inter-dependent, as one phase can influence one or more of the others. For instance, the selection of building materials can reduce heat requirement, but mig ht also inc rease embodied ene rgy and transport -relat ed impacts or affect the service duration of the whole building, and could even influence the generation of recyclable (or disposable) demolition waste. Thus, interest in understanding energy use, consumption ofnatur al resources and pollutant emissions in a life cycle perspective is growing, as acknowledged in a number of studies [1–13]. While in some of these it has bee n confirmed that operation energy is by far the most important contributor to life cycle impacts of conventional buildings [1–4,6,8], in some other cases [7,10–12] it has been pointed out that, especially for new and low energy buildings, the relative role and the importance oflife cycle phases are changi ng. Acc ording to Huberman and Pearlmutter [12], the e mb od ie d e n ergy can beup to60%of the life cycle energy. Therefore, the lower the operation energy, the more important it is to adopt a life cycle approach. Hence, an overall judgment on building sustainability should encompass all the life phases and should be based on an objective and internationally recognised Energy and Buildings 42 (2010) 869–880 A R T I C L E I N F O Article history: Received 2 June 2009 Received in revised form 11 December 2009 Accept ed 26 December 2009 Keywords: LCA Sustainability Low energy building End-of-life Recycling potential A B S T R A C T A det ailed Lif e Cycle Assessment (LCA) has beenconductedon a lowenergy family house recentl y bui lt in Northern Italy. The yearly net winter heat requirement is 10 kWh/m 2 , while the same unit with legal standard insulation would require 110 kWh/m 2 . As the building was claimed to be sustainable on the basis of its outstanding energy saving performances, an ex post LCA was set up to understand whether, and to what extent, the positive judgement could be confirmed in a life cycle perspective. The dramatic contri bution of materi als-related impacts emerged. The shell- embedded materials represented the highest relative contribution, but maintenance operations also played a major role. The contributions ofplants, building process and transportation were minor. The important role of the recycling potential also emerged. Unlike standard buildings, where heating-related impacts overshadow the rest of the life cycle, there is no single dominating item or aspect. Rather, several of them play equally important roles. The study has confirmed that the init ial goalof envi ronment al sustainabil ity was reac hed,but to a muc h lower extent than previ ousl y thought. In comparison to a standard house, whil e the wint er heat requirement was reduced by a ratio of 10:1, the life cycle energy was only reduced by 2.1:1 and the carbon footprint by 2.2:1. ß 2010 Elsevier B.V. All rights reserved. * Corr esponding author at: DISPEA - Depart ment of Production Systems and Business Economics, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy. Tel.: +39 011 209 72 88; fax: +39 011 090 72 99. E-mail address: [email protected](G.A. Blengini). Contents lists available at ScienceDirect Energy and Buildings journal homepage: www.elsevier.com/locate/enbuild 0378-7788/$ – see front matter ß 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.enbuild.2009.12.009
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The changing role of life cycle phases, subsystems and materials in theLCA of low energy buildings
Gian Andrea Blengini a,b,*, Tiziana Di Carlo c
a DISPEA - Department of Production Systems and Business Economics, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italyb CNR-IGAG: Institute of Environmental Geology and Geo-Engineering, Corso Duca degli Abruzzi 24, 10129 Turin, Italyc DICAS - Department of Housing and City, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy
1. Introduction
Lowering energy intensity and environmental impacts of
buildings is increasingly becoming a priority in energy and
environmental policies in European countries. In Italy, such
policies are being integrated in energy strategies and building
regulations at different scales, from national to local, mainly
through direct and indirect actions that are aimed at decreasing
energy requirements during the use phase, with focus on winter
heating.
Although it is reasonable to tackle priorities for improving
the environmental sustainability of buildings starting from the
most energy intensive elements, it should be pointed out that
not only is the use phase a source of environmental concern, but
also the whole life cycle. The overall environmental impacts of
buildings extend beyond the use phase, as they also encompass
the embodied energy and environmental burdens related to
resource extraction and manufacturing, construction activities,
as well as dismantling and construction waste disposal at end-
of-life (EOL).
Moreover, life cycle impacts are highly inter-dependent, as one
phase can influence one or more of the others. For instance, the
selection of building materials can reduce heat requirement, but
might also increase embodied energy and transport-related
impacts or affect the service duration of the whole building, and
could even influence the generation of recyclable (or disposable)
demolition waste.
Thus, interest in understanding energy use, consumption of
natural resources and pollutant emissions in a life cycle
perspective is growing, as acknowledged in a number of studies
[1–13]. While in some of these it has been confirmed that
operation energy is by far the most important contributor to life
cycle impacts of conventional buildings [1–4,6,8], in some other
cases [7,10–12] it has been pointed out that, especially for new
and low energy buildings, the relative role and the importance of
life cycle phases are changing. According to Huberman and
Pearlmutter [12], the embodiedenergy can beup to60%of the life
cycle energy.
Therefore, the lower the operation energy, the more important
it is to adopt a life cycle approach. Hence, an overall judgment on
building sustainability should encompass all the life phases and
should be based on an objective and internationally recognised
Energy and Buildings 42 (2010) 869–880
A R T I C L E I N F O
Article history:Received 2 June 2009
Received in revised form 11 December 2009
Accepted 26 December 2009
Keywords:
LCA
Sustainability
Low energy building
End-of-life
Recycling potential
A B S T R A C T
A detailed Life Cycle Assessment (LCA) has beenconductedon a lowenergy family house recently built inNorthern Italy. The yearly net winter heat requirement is 10 kWh/m2, while the same unit with legal
standard insulation would require 110 kWh/m2. As the building was claimed to be sustainable on the
basis of its outstanding energy saving performances, an ex post LCA was set up to understand whether,
and to what extent, the positive judgement could be confirmed in a life cycle perspective. The dramatic
contribution of materials-related impacts emerged. The shell-embedded materials represented the
highest relative contribution, but maintenance operations also played a major role. The contributions of
plants, building process and transportation were minor. The important role of the recycling potential
also emerged. Unlike standard buildings, where heating-related impacts overshadow the rest of the life
cycle, there is no single dominating item or aspect. Rather, several of them play equally important roles.
The study has confirmed that the initial goalof environmental sustainability was reached,but to a much
lower extent than previously thought. In comparison to a standard house, while the winter heat
requirement was reduced by a ratio of 10:1, the life cycle energy was only reduced by 2.1:1 and the
carbon footprint by 2.2:1.
ß 2010 Elsevier B.V. All rights reserved.
* Corresponding author at: DISPEA - Department of Production Systems and
Business Economics, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129
These results necessarily reflect the complex combination of
the case study building unique features, the locally adopted
construction techniques, the behavioural pattern of Italian citizens,
site-specific climate conditions, local regulations and the Italian
energy mix. Therefore the results should not be generalised,
although some general remarks can certainly be given.
These findings emphasise the need for systematically verifying
the environmental performance of future low energy building
using a holistic approach, as single improvements might not be
effective in a life cycle perspective, and could even disappoint
expectations.
Energy and environmental certification schemes, in Italy and
elsewhere, wouldcertainly benefit from the adoption of a life cycle
approach, but it should be kept in mind that excessive simplifica-
tions, generalisations and blind reliance on user-friendly tools and
non-transparent databases still remain a real threat to genuine
sustainable development.
Acknowledgements
The authors wouldlike to thank Studio Roatta Architetti Associati
in Mondovı for the data and information supplied, the staff of
Regione Piemonte for the support, Msc. Agnese Fiorenza for her
help in the data collection and elaboration.
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.enbuild.2009.12.009.
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