Retrotec USACE - Manual (Page 400)

K12 ENERGY & PROCESS ASSESSMENT PROTOCOL
Hence, global recommendations for energy assessment protocol for old
buildings are as follows:
Identify the traditional building techniques according to the age of old ■
buildings.
Understand the thermal behavior of the whole old building, with its
■
active and passive measures.
Have a bioclimatic approach of the old building to understand the
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energy consumption.
Study the thermal behavior of the building in winter and summer.
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Consider that the most effi cient energy savings are often passive mea- ■
sures (without equipment).
Do not create thermal bridges in old buildings where they do not exist.
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Do not propose energy savings solutions that may bring about structural ■
disorders.
Old buildings and modern buildings differ in several holistic characteristics
and their subsequent energy impact (Table K1):
TABLE K1. SOME DIFFERENCES BETWEEN OLD AND MODERN BUILDINGS FOR
ENERGY ASSESSMENT.
Old buildings Modern buildings
• Local materials and building design used during several centuries
• Location and orientation according to sun path, wind, and precipitation
(strong thermal interaction with microclimate)
• Indoor distribution with crossing rooms according uses
• Thermal buffer zones
• Specifi c optimized openings
• Materials very sensitive to water (variable U-value) but with a good dimen-
sional stability
• Signifi cant use of plaster and superfi cial coatings allowing the absorption of
air humidity without disorder (rooms without heating or cooling systems)
• Heavy structural masonries with strong thermal inertia inside the facades
and distribution walls
• Diversity of walls on the same fl oor according to use (representative stones
on the street side and wood side on the backyard)
• Diversity of wall thickness with structural constraints according to the fl oors
(reduced thickness for the higher fl oors)
• Wooden fl oors reasonably well insulated with good energy performance
• Materials fi lling partitions and fl oors with hygrothermical regulation properties
• Few thermal bridges in facades because of traditional building techniques
• Developed building systems according to new demographi-
cal, economical, and industrial constraints
• No optimization of climatic constraints: location, orientation,
openings, etc.
• Choices infl uenced by urban regulations
• Indoor distribution according general models in order to cre-
ate spaces independent of local environment.
• Industrial materials insensitive to water but sensitive to ther-
mal dilatations.
• Few absorptive materials inside the building
• Identical and prefabricated walls with limited thickness
• All walls are identical, industrialized, horizontal, and vertical
• Standardization of building design without any distinction
between structural walls and facades.
• Full concrete fl oors with heat transfer between different fl oor
levels
• Secondary materials with mainly an aesthetical role
• Signifi cant thermal bridges because of building techniques
with jointed prefabricated elements