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
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
