Case Study: nZEC - Energy refurbishment of 194 dwellings in the residence Les Roches, Nantes, France

Name of organisation: LogiOuest

Stage of development: completed

Year of finalization: 2012

Type of project: refurbishment

Area: urban

Scale: group of buildings

Type of building: Apartment in a block of five or less stories

Number of units/dwellings: 194

Tenure: social rental

Street: 1, Avenue Grippa d'Aubigné

Postcode: 44300

City: Nantes

Region/ County: Pays de la Loire

Country: France

Last Update: 17.04.2015

Funding Project Management Certification Thermal Insulation Ventilation Water Saving

Short Description

The aim of this refurbishment project was to improve the energy performance of the building but also to improve the living environment of the tenants, and to decrease the heating bill for the tenants.


Key Elements

Certification

On a scale from A to G, the level of the building after refurbishment is B, with an annual consumption of 84kW(primary energy)/m²

A: <50, B: 51<  <90, C: 91< <151, D: 151< < 230, E: 231< <330, F: 331< <451, G: >451


Funding

Different sources of founding were solicited to assemble this project: ERDF funds, fundings from the Région, specific loans.


Costs:

Consequential costs

No problems occurred during the project

VAT

5.5%

Monitoring equipment

0

Research and development costs

0

Operation, inspection and service

4.171 €/year all taxes included (Operation control)

Maintenance – repairs and replacement

Heating and Hot Water

P2 Contract (Management and Low Maintenance Level): 6.585 €/year all taxes included

P3 Contract (High Maintenance Level and Replacement of Equipments): 3.953 €/year all taxes included

Energy tariff

Contract for heating and hot water: 102.405 €/year (fuel + electricity of the boiler room included)

Energy savings estimated : 59 269€/year

Public financial assistance

ERDF, Regional fundings




 

Thermal Insulation

The prefabricated panels of the original building were insulated from outside, thanks to a cladding on a wooden framework with as insulating material glass wool. This external insulation enabled to eliminate thermal bridges. Concerning the insulation of the building, terrace roofs were also reinsulated.


Ventilation

An automatically controlled mechanical ventilation was installed.


Water Saving

Equipments enabling water savings were set up in the dwellings (less consuming flushes, equipments for taps).


Project Management

It is important to stress that a preliminary energy audit was carried out and the prime contracting performed a diagnosis and wrote the tendering package.


Main Results

The level of energy consumption and the CO2 emissions of the building before refurbishment was:

  • Energy: 175 kWh/m²/year (level D)
  • CO2 emissions: 37 kgCO2/m²/year (level E)


The level of energy consumption and the CO2 emissions of the building after refurbishment is:

  • Energy: 85 kWh/m²/year (level D)
  • CO2 emissions: 16 kgCO2/m²/year (level C)


The energy savings are estimated to 59.269 €/year.


Lessons learned

No specific problems occurred during the construction. The key point of this project is the improvement of the energy performance (90kWh/m² are saved each year thanks to the retrofit). Moreover, the image of these buildings, in terms of attractiveness, changed. We assist to an upgrade of these buildings.


Additional Information

Ms Carine Puyol
USH - The French Federation of Social Housing Providers
E-mail: carine.puyol@union-habitat.org
Web: www.union-habitat.org


Source: http://www.powerhouseeurope.eu/nc/cases_resources/case_studies/single_view/?tx_phecasestudies_pi3%5Bid%5D=164&tx_phecasestudies_pi3%5Bdisplaytype%5D=overview&cHash=