Case Studies

Single Family House Renovation, Papagou

Papagou, Greece

Code: CS2

View from the outside
New PVC window installation
New PVC window installation

Original situation

A 1970s single family house with 150 m2 of treated floor area, featuring a flat, uninsulated roof and an uninsulated brick façade with a floor slab 2.4 m above ground. The home has double-glazed but non-thermally broken aluminium windows and poor airtightness (an n50 value of 8 air changes per hour as compared to the standard Passive House level of 0.6) with some 20m of balconies that contribute to extensive thermal bridging.

Renovation approach

The renovation approach is the streamlined approach with conventional methodology of construction. Prefabricated materials and systems are still expensive in Greece because we must import everything.

Modernisation proposal

To split the house into two apartments , one 100m2 and one loft 50m2! To update the dimensions of some windows in order to improve the solar gains. to insulate the whole envelope , which is totally uninsulated , in order to cut heating by factor 15 and eliminate several thermal bridges. To put ventilation systems with HR in both apartments in order to increase thermal comfort and air quality. To reach the EnerPHit Standard by replacing old, inefficient components with Passive House certified ones.

Efficiency improvement

According to current planning, heating demand will be reduced by a factor 15 and cooling demand by factor of 6.

PHPP verification sheet before retrofit

PHPP verification sheet after retrofit


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Key facts

Building typology

Two family house

Existing treated floor area (usable floor space)

150 m2

Building owner

Aris Georgopoulos

Consulting outphit partner


Project status

Construction phase

Overall budget

80 000 €


Sofia Piperou
Hellenic Passive House Institute (HPHI)
Phone: +30 211 4081109