Economic and environmental impacts of several retrofit options for residential buildings

Nowadays, important efforts are deployed to reduce our actual residential building
consumption which represents about 40% (25% for the residential sector and 15% for the
non-residential sector) of the total energy consumption in Europe. The aim of this paper is to
evaluate the environmental and economical impact of several retrofit options for residential
buildings. Our study focuses on the Walloon Region of Belgium. A “bottom-up”
methodology is applied: this methodology focuses first on a micro-analysis. Results from this
micro-analysis are then used and extended to a macro-analysis. The presented methodology
does not permit to determine with precision the global consumption of residential buildings in
the Walloon Region. However, the latter methodology allows pointing out some economical
and environmental trends related to the different investigated retrofit options.
The first part of this end-of-study work offers an overview of the Walloon building stock by
presenting statistic data on the Walloon residential houses. From these latter statistic data, it is
possible to divide the Walloon building stock by means of arborescence. Each type of
building is characterized by constructive data (mean area, Uwall, Uwindow…) and by heating
production system efficiency.
Thanks to these data, it is possible to determine the gas and electrical annual consumption for
each type of residential building by means of a computer program that simulates residential
building.
The latter computer program is also used to determine the annual energy consumption of
envelope retrofitted houses. Retrofit options related to heat and/or cool production are also
investigated.
A macro-point of view study is carried out in order to determine the potential of energy
saving of each investigated options. An environmental comparison between the several
envisaged retrofit options is realized in terms of CO2 emission, final and primary annual
energy consumption for each type of building.
An economical study is carried out in order to determine the profitability of each investigated
options for citizens.
The work also proposes a reflection about the actual incentive policies.