Project 103

  • Building Type : Isolated or semi-detached house
  • Construction Year :
  • Delivery year : 2018
  • Address 1 - street : rue des Américains 103 7022 HYON, Belgique
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 293 m2
  • Construction/refurbishment cost : 178 000 €
  • Cost/m2 : 607.51 €/m2
  • Primary energy need :
    44 kWhep/
    (Calculation method : RT 2012 )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building

"Projet 103" consists of the renovation of an old and unhealthy house. The objective was to reach the "Q-ZEN" energy standard (2021 standard in the Walloon Region, Belgium) at the end of the renovation while doing without fossil fuels: only a wood stove provides heating for the house.

The programme includes insulation of the envelope (with, in particular, bio-sourced insulation for the roof: Gramitherm), careful airtightness, double flow ventilation and photovoltaic panels. 

The label of the house is A+, which is better than what is required for a new house in 2021. 

Data reliability

3rd part certified

Photo credit

Elie Delvigne
Cecile Hoyos
Denis vasilov


Construction Manager


    Elie Delvigne



    Homeco architecture

    Xavier Bachelart


Owner approach of sustainability

The aim was to carry out a renovation (environmental impact of a renovation vs. new construction) of a house in an urban context (proximity to services, public transport, etc.).

The objective of the renovation was to show that it is possible to achieve high energy performance (A+ label) without the use of fossil fuels (only a wood-burning stove heats the house) and by using bio-based materials (gramitherm insulation on the roof).

The consumption of the house is currently 0 € (wood recovered from neighbours, electricity compensated by photovoltaic panels).

In terms of biodiversity, a permaculture vegetable garden, a greenhouse and a henhouse have been installed. 

Architectural description

Work on the building envelope:

- external insulation of walls ;

- insulation of the attic floor;

- triple glazed aluminium joinery;

- insulation of the floor slab and the cellar ceiling; 

- work on the airtightness. 


- Heating by wood stove (independence from fossil fuels); 

- Domestic hot water by electric boiler (simplicity of installation); 

- double flow ventilation system with heat recovery; 

- photovoltaic panels to compensate for electricity consumption. 

Energy consumption

  • 44,00 kWhep/
  • 510,00 kWhep/
  • RT 2012

  • 40,00 kWhef/
  • According to the PEB certification method: 79% heating, 15% DHW, 6% auxiliaries

    Consumption = 0. Wood recovered when cutting trees, electricity consumed offset by photovoltaics

  • 658,00 kWhep/

Envelope performance

  • 0,33 W.m-2.K-1
  • Roof insulation with Gramitherm insulation, facades insulated from the outside with plaster on EPS insulation, floor slab insulated with icynene foam. Triple glazed aluminium joinery.

  • 0,62
  • n50

  • 5,00
  •  Test blower door


    • Wood boiler
    • Individual electric boiler
    • No cooling system
    • Double flow heat exchanger
    • Solar photovoltaic
    • Wood boiler
  • 100,00 %
  • Solar photovoltaic system installation composed of 20 panels of 270 Wc

GHG emissions

  • 1,00 KgCO2/m2/an
  • Certification PEB

  • 120,00 KgCO2 /m2
  • 50,00 an(s)

Water management

  • 30,00 m3
  • 40,00 m3
  • 10,000-litre rainwater tank which supplies the toilets, the washing machine and the outdoor taps used for the vegetable garden

Indoor Air quality

    The double flow ventilation ensures a constant and continuous ventilation of the building. 

    Solvent-free paint was used to paint the walls (Belgian brand PEINTAGONE). 

Urban environment

Existing house on the outskirts of an urban centre (city of Mons). 

A bus line passes in front of the building (bus stop a few dozen metres away).

A cycle track is in front of the building (see photo). 

A permaculture vegetable garden has been set up in the garden with a chicken coop and a greenhouse. 

Parking spaces

Parking spaces are located on the side of the building.
Annex buildings accommodating bicycles.




    [email protected]

    Second œuvre / Cloisons, isolation

    Grass-based insulation

    Happy to test this bio-based, innovative and local solution

    Double flow ventilation


    Génie climatique, électricité / Ventilation, rafraîchissement

    Double flow ventilation

    Improved air quality, night cooling in summer

    Wood stove


    Génie climatique, électricité / Chauffage, eau chaude

    Wood stove

    Wood stove "heat", independence from renewable energy

    Photovoltaic installation

    JA Solar

    20 solar panels of 270 Wp

    Electricity bill at 0

    Solvent-free paint


    [email protected]

    Second œuvre / Peinture, revêtements muraux

    Velvety matt acrylic paint, almost solvent-free and plasticizer-free, very washable.

    Solvent-free paint used throughout the house to minimise the air quality impact of finishes

Construction and exploitation costs

  • 1 500,00
  • 6 900,00
  • 190 000
  • 30 000
  • The renovation cost 600 € / m² HVAC

Building Environmental Quality

  • indoor air quality and health
  • biodiversity
  • works (including waste management)
  • comfort (visual, olfactive, thermal)
  • water management
  • energy efficiency
  • renewable energies
  • products and materials

Reasons for participating in the competition(s)

The main objective of the project is to show individuals and professionals that it is possible to achieve high energy performance in renovation. The building has an A+ label (better than the requirements for new buildings in 2021).

The second objective is to show that the first is achievable by using locally produced bio-sourced materials (Gramitherm, grass-based insulation, produced in Auvelais, Belgium). 

Finally, the third objective is to do without fossil fuels in order to reduce the carbon footprint of the building as much as possible. 

Building candidate in the category

Energie & Climats Tempérés

Energie & Climats Tempérés

Green Solutions Awards 2020-2021 / Candidats belges


Author of the page

  • Other case studies



    Green Solutions Awards 2020-2021 / Candidats belges