Case Studies

Non-residential building from the 1960s

Lons le Saunier, France

Code: CS9

© R. Claret, Ajena

Original situation

1960s concrete non-residential building on the outskirts of Lons le Saunier. The building is used by AJENA as a centre for training on retrofitting, so a well renovated building would be a big plus.

Renovation approach

A prefabricated wall to the north (windowless) and on the south wall, wooden caissons (boxes) mounted onsite to support the insulation. Ventilation with high performance heat recovery. Increased airtightness throughout and reduced thermal bridging to be achieved through the use of prefab elements and exterior insulation.

Modernisation proposal

A complete energy retrofit to EnerPHit level using some prefabricated elements: a prefabricated North wall and South wall that will be mounted on-site. Triple glazing and ventilation with heat recovery will be added.

Efficiency improvement

The improvement that an EnerPHit renovated building can offer is huge in this cold part of Jura near Geneva, reducing heating demand by a factor of 10.

PHPP verification sheet before retrofit

PHPP verification sheet after retrofit

Key facts

Building typology

Office | administration building

Existing treated floor area (usable floor space)

285 m2

Building owner


Consulting outphit partner


Project status

Construction phase

Overall budget

550 000 €


Etienne Vekemans
Phone: 0145081335