Solar Energy Perspectives - IEA

Chapter 4: Buildings
Défense near Paris, the First Tower, built on the remains of the Axa Tower, requires
five times less energy for space heating and twice less for air-conditioning than its
predecessor. If renovation from outside is impossible, renovation from inside can take
place but usually only through deep refurbishing as most of the plumbing, electricity and
finishes will have to be redone. This will often entail some loss of interior space, as thin
insulation materials are still under development. Limited renovation (changing windows,
insulation of roofs and sometimes of the ground floor), does reduce energy consumption,
but to a smaller extent. It has been argued, however, that continuous energy efficiency
improvement based on scheduled refurbishment would ultimately drive more global
energy cuts for similar expenses than more radical but costlier “all-at-once” renovation
(Acket and Bacher, 2011).
Photo 4.4 Frankfurt refurbishment using passive house technology
Notes: Top photos show the building before and after the refurbishment. Bottom images show infrared visualisation of the heat losses
before and after the refurbishment.
Source: Passive House Institute Darmstadt, government-funded by the Ministry of Environment, Energy, Agriculture and Consumer
Protection of the State of Hesse.
Key point
Building renovation can reduce energy expenses sevenfold or more.
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© OECD/IEA, 2011