Retrotec USACE - Manual (Page 389)

K1
Appendix K
Special Features to Consider in Energy
Assessment of Old Buildings
K.1 Interactive Energy Subsystems of Old Buildings
Many government buildings are old buildings with strong historical, patrimo-
nial, and architectural characteristics. In many countries, there is a large stock
of old buildings. In France, for instance, a third of the existing buildings were
constructed before 1948. There is a similar percentage of older (pre-1960)
buildings in the Canadian government building stock and in some other Euro-
pean countries. Most of the buildings of this period were not cooled, had oper-
able windows, and made greater use of natural lighting and ventilation.
As regards energy performance, the stock of existing buildings is not a ho-
mogenous group. It varies in nonlinear and uncertain ways according to the
age of the buildings.
The years 1930–1950 were a transition period that brought real changes in
building construction methods.
New ways of building were made possible by following elements:
Availability of new manufactured building materials easier to use (rein- ■
forced concrete fl oors, post-beams structures, concrete blocks), with
diverse and nonstationary hydrothermal properties
Limitations of town planning due to real estate market that made it dif-
■
fi cult to build in relation to the immediate environment (orientations
according to sun and wind)
Economic and profi tability limitations of the building sector due to a
■
massive demand for buildings
Thermally, there is an important change from an architecture that was
taking into account the climatic environment, using local resources and materi-
als, to an industrialized architecture using new building materials with diverse
hydrothermal properties. At the same time, designers, having new techniques
at their service, tend to ignore the local conditions of each site. The 20th cen-
tury saw the beginning of the production of modern buildings: they are venti-
lated, heated, and artifi cially lit.
The fi rst international oil crisis and the fi rst thermal building regulations
also drew a line of essential fracture in the history of architecture. Since the
1970s, the requirements for the insulation of buildings have been considerably
reinforced and regularly updated.