20 Boétie

Last modified by the author on 20/05/2015 - 14:28


  • Building Type : Office building < 28m
  • Construction Year : 2013
  • Delivery year : 2014
  • Address 1 - street : 20, rue Boétie 75008 PARIS, France
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 3 961 m2
  • Construction/refurbishment cost : 11 800 000 €
  • Number of Work station : 250 Work station
  • Cost/m2 : 2979.05 €/m2

Proposed by :

Certifications :

  • Primary energy need
    66 kWhep/m2.an
    (Calculation method : )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building

Located in the Central Business District, thisbuilding built in 1878 displays its new identity and fits perfectly into itsenvironment by combining historic facades to contemporary glass elements;Haussmann of roofs vegetated roof terrace; heritage spaces with elementspreserved and modern spaces.

Redesigned in a logic consistent with the ambitions ofthe Grenelle II Environment and fully restructured in order to make a building"new": effective insulation on roof, reversible heat pumps,optimization of energy management via centralized building management, recoveryof rainwater, revegetation of the inner courtyard terraces and roof terraces:building 20 Boétie is certified NF Tertiary buildings HQE NF certificate No.380-12 / 1022 and certified HPE Effinergie Rénovation® certificate No.2015/555.

ADEME Ile-de-France wanted to support developers inachieving BBC® building through a grant awarded to the winner of a call forprojects BBC.

Renovation: After renovation, the buildingreached a draft Cep Cepref below -50%, GHG emissions have been lowered to less 5kgCO2/ m².year the air permeability of the casing is 1.2 m3 / h *m². Its performance allows it to be certified HQE NF Tertiary BuildingsCertificate No. NF 380-12 / 1022 and certified HPE Effinergie Rénovation®Certificate No. 2015/555.

Smart Building: Over 200 sensors were installed on the building tomeasure the different data (temperature, humidity, air quality, lighting,presence detectors ...) and optimize the operation of the building viaa specific GTB in operation.

Sustainable development approach of the project owner

Nacarat is a developer fully committed to sustainable development. That's why an eco-design approach is consistently applied for all Nacarat programs since 2011. This project in downtown Paris is emblematic of this approach. The objective is to always go as far as possible in terms of performance, in the largest number of possible fields of action while keeping the operation within market prices.
In the 20 Boétie operation, the strategy consisted in pushing energy efficiency as if the building was newly constructed, while keeping it invisible or at least elegant. In addition, user comfort was increased by GTB controlled indoor air quality and by revegetation of a very constrained site (inner courtyard and high walls)

Architectural description

The 20 Boétie building is now modern and efficient office building that preserves the memory of the past thanks to the conservation of heritage areas and historic features. It is also a building where it feels good to work in, because the roof tops and the courtyards have been revegetated, thus creating pleasant environment for the inoccupants but also for local residents while reducing the leakage flow of rainwater and the the heat island effect.

Building users opinion

The building was sold but not yet occupied in June 2015.

If you had to do it again?

Nacarat is quite ready to replicate such innovative projects: energy renovations are fascinating.

See more details about this project




    Nacarat, agence Ile de France, groupe Rabot Dutilleul

    Sophie Galmard


    Director of corporate real estate programs

    Thermal consultancy agency




Contracting method

Other methods

Energy consumption

  • 66,00 kWhep/m2.an
  • 148,00 kWhep/m2.an
  • Heating: 25.5
    Cooling: 3.5
    Hot water: 0
    Lightiing: 13.45
    Auxiliaries: 24.2

  • 1 027,00 kWhep/m2.an

Envelope performance

  • 0,52 W.m-2.K-1
  • All architectural arrangements have been made to limit the energy needs, in particular, those of cooling. As such a dynamic thermal simulation was conducted by thermal BET CORETUDE to work on the following:
    • Sunscreens windows and solar factor of the glazing according to their different orientations,
    • implementation of a ventilated roof on roofs East, West and South Zinc

    EN 13829 - q50 » (en m3/h.m3)

  • 1,20


    • Heat pump
    • Low temperature floor heating
    • Individual electric boiler
    • Reversible heat pump
    • Fan coil
    • Nocturnal Over ventilation
    • Double flow heat exchanger
    • No renewable energy systems

    Surtoiture en zinc à + 15 cm, perforée qui protège la toiture "réelle" et surtout les locaux sous toiture: gain calculé 2°C.

Smart Building

    YES. Hardware Trend, a software specifically developed by the companies CORE STUDY and HSP

Urban environment

  • 1 135,00 m2
  • 82,00 %
  • 200,00
  • Ultra modern refurbishment of a XIXth century building a few hundred meters from the Champs Elysées. Parisian hypercenter, totally mineral-out at the beginning of the project. The revegetation of some areas (roof and walls) provides significant benefits. Paris Mobility: high functional diversity; strong automotive difficulty; easy gentle mobility even if the use of bicycles can be complicated given the trafic.




    Responsable Commercial


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    The advantages of VERTIFLORE facades:
    • Aesthetics
    • Sound Attenuation: B3 / Rw = 61db (test by CSTB)
    • Sound absorption: A4 / Dla = 14DB (aw = 1.00 Class A) (test by CSTB)
    • Thermal insulation (limitation of the effect of urban heat island)
    • Reintroduction of biodiversity
    • Pollution Control of ambient air (oxygen release and retention of CO2 and dust)
    • Fire resistant (M1) (test by CSTB)
    • Resists seismic waves : can be installed in Zone 5
    • Maintenance consumes little water and no fertilizer

    No problem

Construction and exploitation costs

  • 11 800 000
  • 120 000

GHG emissions

  • 5,00 KgCO2/m2/an
  • via the regulation calcultation by CORE STUDY

  • 240,00 KgCO2 /m2
  • 100,00 année(s)
  • Rabot Dutilleul proceeded in 4 Carbon Footprint scope3. More than 2/3 of emissions come from reinforced concrete. This ratio can't be used here because it is a full refurbishment.

Life Cycle Analysis

    More than 90% of deconstruction and construction waste was recovered.

Reasons for participating in the competition(s)

​Ancient building in downtown Paris, refurbished to a low consumtion level: a great and beautiful adventure.
3rd Industrial Revolution:- Energy Efficiency
Green Building Solutions Awards 2016

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Author of the page

Rodolphe Deborre

Directeur Innovation et Renaissance Ecologique

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Green Building Solutions Awards 2016