Thermography of Parisian Buildings

Extract of the aerial thermography of Paris

In response to the City of Paris' demand the Apur carried out an aerial themography of the territory and the exterior walls of  500 representative buildings.
This technique is a precious tool for detecting flaws in the insulation of buildings. Associated with  complementary expert knowledge thermography permits recommendations to be established for improving the thermal functioning of Parisian buildings.

This work was presented to the general public in the form of a exhibition (downloadable below) last October during the Second Parisian Energy and Climate Days -Deuxièmes Journées parisiennes de l’énergie et du climat-.
The exhibition will continue to be shown at organised conferences at Local Town Halls until the end of 2010.

A study included in the Apur's 2010 work program will analyse Parisian buildings and their evolution in greater detail, with specific studies dealing with housing and pockets of heat.
The objectives and methodological principles of the coming study are listed below.

The Issue of Thermography

In France the sector of residential and tertiary buildings makes up 42% of the national energy consumption and approximately 1/3 of greenhouse gases. (GES-gaz à effet de serre-). In view of the national objective to reduce GES emissions by 4 by 2050 this sector takes on a highly symbolic role. It is in fact one of the rare occasions where existing technical solutions, already available on the market, allow emission reduction objectives to be reached.

The objective of the present study is to understand how to put into action, in practical terms, an ambitious policy to reduce GES emissions in the Paris building sector. Addressed to social housing organisations and co-owners of the capital, the study concentrates on the residential segment of Parisian buildings. At the outcome of the analytic work  a few case studies may be carried out on tertiary buildings on an exploratory basis.

Problems of the Study

The renovation of existing buildings is today a subject of study in a paradoxical situation with on the one hand political decision makers expecting a great deal from it and on the other a very small amount of documentation on the value of possible practical solutions. The debate on the subject is often oversimplified and very often reduced to the opposition between old, non-insulated buildings considered to be wasteful and perfectly insulated, recent buildings considered to be efficient. This kind of observation leads to buildings being systematically weatherstripped which in many cases can have disastrous consequences on the structural solidity of the building,  the comfort of its inhabitants and the energy consumption in summer (due to air-conditioning).

The present study aims to show how each building in Paris is the product of a historical context and that it possesses thermal qualities and faults  inherent to the construction methods of its period. During the study we will analyse the thermal performance of buildings, taking into account all elements of thermal comfort such as ventilation, the humidity level, their capacity to bear the thermal shock of summer, etc... Also, given that within Paris types of social housing are widely diverse, a large part of them being old, (75% of residential buildings of the capital were built before 1914) a particular framework in which to reflect on the subject is necessary. Elements of heritage are essential components to be considered when doing research to find innovating solutions to improving the thermal functioning of a building (action carried out on heating systems, insulation of exterior  walls, green roofing...)


The energy label is today an element which allows the general public to understand better the energy consumed by buildings. However, one must remember that the thermal efficiency of a building cannot be reduced to a figure expressed as  kW h/m2/yr, and that pertinent and sustainable solutions for reducing energy consumption require that a certain number of criteria be analysed in detail:

  • materials used in buildings
  • existing insulation techniques
  • the state of the building prior to renovation
  • architectural and heritage value
  • the financial capacity of co-owners
  • energy consumption objectives to be achieved (in accordance with those of the Grenelle2 Climate Plan)

The work method of the study has therefore been structured around three complementary approaches to thermal analysis of Parisian buildings.

The first approach consists of putting buildings into their construction context, by clarifying their specific urban form and the building techniques of each period studied. The aim is to provide keys for interpreting their thermal analyses and references for when analysing possible solutions. To achieve this, work is based on field surveys and documentary research from either existing documentation or building plans (particularly when social housing organisations or co-ownerships can make them available to the Apur).

The second approach consists of deciphering the building from a thermal point of view. To do this, work is based, among other things, on the analysis of the  thermography  of exterior walls, carried out on  a representative cross section of Parisian buildings. This allows observation of the different thermal behaviour inherent to buildings of each period studied, emphasising possible assets and pathologies.

The third approach consists of carrying out a critical study of existing solutions for improving thermal performances  of buildings and to confront them with the actual context of the Parisian territory. To do this, analysis is bases partly on feedback from the experience of the principal operations carried out by social housing organisations who are partners of the study and also on low cost, energy saving simulations carried out on examples of the study's selected  sample buildings.

The methodology relies on the Apur chronologically dividing buildings into 9 periods,  inspired by those proposed by the INSEE (National Institute for Statistics and Economic Studies) for the period prior to 1915, thus making it easier to identify all periods of Parisian building construction.

A Detailed Plan of notebooks by period

In accordance with the elements we have just presented and on each period studied, the study plan is the following.

1- The construction context and urban form specific to each period, to understand the evolution of Parisian buildings and to gather information on the issue of a sustainable city the following elements are systematically treated:

- the demographic context

- the economic context

- the environmental context

- the analysis of the urban form, notably taking into account:

        • the  distribution of buildings on  Parisian territory

        • the evolution of the density and compactness of areas. The objective being to explore the link between the urban form and the thermal performance of buildings

2 The architectural analysis of residential buildings from each period represents successively:

- the state of the building techniques of the period

- the types of buildings found within each period. For each type, their main architectural characteristics are made evident, linked either to their thermal behaviour or the types of thermal performance improvement solutions possible.  For each period the following are systematically  treated:

        • the building techniques (framing or  bearing exterior walls, prefabrication

        • the outer surfaces of buildings (types of material, ornamentation, presence of balconies, loggias, oriel windows, types of door jambs......) and roofs

        • heating systems (collective, individual..) and the energy source used ( gas, electricity...)

        • the type of ventilation (natural, mechanical...)

        • the dimensions of accommodation (height of ceilings...)

        • the organisation and layout of rooms

3.  Thermal analysis of types of buildings found within each period studied, examine successively:

- the behaviour of walls through 4 parameters

        • their thermal resistance

        • their behaviour in varying temperatures (the cold wall phenomenon..)

        • their behaviour with humidity phenomena (dew point...)

        • their inertia, to consider the issue of comfort during summertime

- the possible presence of thermal leakage, in three areas

        • at floor level

        • at windows and door frames

        • the ventilation of accommodation, an important element particularly in the case of applying insulation techniques to exterior walls

- heating systems

4. Samples of improvement work on the thermal performance of buildings within the periods studied, with the intention of examining all possible solutions. Simulations will also be carried out to test the value of different possible operations.

The conclusion, in the form of a synthesis of warnings and recommendations  proposed, for the period studied, in accordance with the architectural and thermal specifications of period buildings. The feedback from experience will also allow a critical analysis of the durability of operations carried out and if they should be repeated, the evolution of their performance over a period of time and their value as a means to save on energy consumption.



Documents to download

  • Map dating Parisian buildings 2009

    Format : pdf, 1.35 MB
  • Thermography of Parisian buildings – exhibition posters

    Format : pdf, 1.62 MB
  • Aerial thermographies of the 1st, 2nd, 3rd and 4th districts

    Format : pdf, 2.1 MB
  • Aerial thermography of the 5th district

    Format : pdf, 1.8 MB
  • Aerial thermography of the 6th district

    Format : pdf, 1.82 MB
  • Aerial thermography of the 7th district

    Format : pdf, 1.94 MB
  • Aerial thermography of the 8th district

    Format : pdf, 1.98 MB
  • Aerial thermography of the 9th district

    Format : pdf, 1.99 MB
  • Aerial thermography of the 10th district

    Format : pdf, 2.01 MB
  • Aerial thermography of the 11th district

    Format : pdf, 2.09 MB
  • Aerial thermography of the 12th district

    Format : pdf, 1.82 MB
  • Aerial thermography of the 13th district

    Format : pdf, 1.85 MB
  • Aerial thermography of the 14th district

    Format : pdf, 1.95 MB
  • Aerial thermography of the 15th district

    Format : pdf, 1.94 MB
  • Aerial thermography of the 16th district

    Format : pdf, 1.91 MB
  • Aerial thermography of the 17th district

    Format : pdf, 1.98 MB
  • Aerial thermography of the 18th district

    Format : pdf, 2 MB
  • Aerial thermography of the 19th district

    Format : pdf, 1.94 MB
  • Aerial thermography of the 20th district

    Format : pdf, 2.01 MB