Case Studies

Zusammenfassung

A single-family EnerPHit retrofit in Darmstadt, Germany.

Original situation

The building is a typical multi-story residential building of the 1950s and 1960s in Germany with masonry walls and reinforced concrete floors that form the supporting structure. The buildings have gable roofs, the staircases are slightly set back. The original windows had previously been replaced with plastic windows and partly by wooden windows with 2-pane thermal insulation glazing.
The building fabric consists of 30cm of masonry walls and reinforced concrete ceilings as well as an almost uninsulated gable roof and a massive basement. The façade has a brick wall surface that had not been renewed so far. Neither had the pitched roof attic and basement ceiling been notably insulated. Only the original windows had been replaced during the 70s by PVC windows in the quality available during that time.
The building in original state was not at all comfortable to live in during winter times. The family was living there for about 10 years before they decided to renovate, reported that they hardly succeeded to get comfortable indoor temperatures during winter from early September to late April.
Heating in the original state was covered by central gas heating. Ventilation was provided by opening the windows. There was no active cooling is the building – all windows have roller shutters to prevent overheating.

Renovation approach

The building has been renovated, post occupancy monitoring is in progress.

Renovation approach document

Modernisation proposal

The building envelope of this small building was renovated with the intention of using on-site small scale insulation parts. The main reason to do so was the small scale dimensions of all wall and roof areas: no part of the building was similar to the other. So the wooden beams which build-up the cavity for the cellulose fiber filling were provided individually on top of the old rafters and all along on the outside walls. On top of the new beams, a 6 cm wooden fiber board was installed to close the cavity. All windows were then installed on these beams, which formed a 'perfect' installation frame so that the windows could be moved out into the insulation layer. Nevertheless the conception and the construction to provide a good airtight shell was straight forward.

Heating and hot water are supplied by an externally installed multi-split-heat-pump-device.

Efficiency improvement

Renovation measures will cut the demand for heating by around 85 %.
Predicted energy savings:
Savings In space heating demand:    260 [kWh/(m²a)]
Savings Primary Energy Demand:    319 [kWh/(m²a)]
Savings PER Demand:    549 [kWh/(m²a)]

Savings of Final energy demand gas:    342 [kWh/(m²a)]
Savings of Final energy demand electricity:    0 [kWh/(m²a)] Household appliances not updated
Additional final energy demand electricity:    34 [kWh/(m²a)] Heat pumps for Heating and DHW

The building will receive solar PV elements on the south roof after finalization. A PV yield of even 85 kWh/(m²a) could be possible, if most of the roof area would be covered with PV panels.

Video

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Link of materials related to the project that could be useful and/or of interest