Name and Address
Name of the demo site: NHT IN28
Address of the demo site: Fennerstraße & Oswald-Redlich-Straße/ IN 28, 6020 Innsbruck, Austria
City map highlighting the surface occupied by the demo site (source: http://city-map.innsbruck.gv.at)
NHT already finished the innovative overall building renovation, consisting of the process innovation (e.g. tenants involvement process, implementation of ventilation system etc.) and the technical components of the refurbishment (e.g. insulation, PV on the rooftop, etc.). Issues such as apartment entrance doors and a new locking system have been completed. NHT is fully satisfied with the completed refurbishment of IN 28. NHT convinced the tenants of the meaningfulness and the positive aspects of the ventilation system during the refurbishment of IN 28.
Ownership: Neue Heimat Tirol (NHT)
Gross conditioned floor area (EPC): 7.359 m²
Treated floor area (PHPP): 5.919 m²
Number of dwellings: 84
Heating demand (EPC)
BEFORE RENOVATION: 60,9 kWh/m²*a
AFTER RENOVATION: 23,8 kWh/m²*a
Heating demand (PHPP)
BEFORE RENOVATION: 112,3 kWh/m²*a
AFTER RENOVATION: 17,9 kWh/m²*a
Overall savings after completion of ventilation & heating system: >80%
All objects are patched via 1 long complex of buildings and 1 small one.
IN28 is typical building block constructed in the second half of the 20th century with related challenges in regards to insulation, electric cables, low performing windows, uninsulated roofs and cellars, etc
Technical system: Decentralised heating system
Energy performance certificate: Category C
Thermal renovation of the walls, the ceiling, the roof and the windows with triple-glazing. The thermal bridges of the balconies were minimized through insulation of the floor of the balconies.
The PV system will be installed as a full feed system so that the generated energy will feed the public grid while the Austrian agency for green electricity compensates the missing power.
Replacement of windows to reach app. 70 % better thermal performance.
Target is to achieve a calculated energy consumption per m² of total used conditioned floor area of about 24 kWh/m²*a (EPC). In addition electricity savings between 30 – 40% should be achieved.
The refurbishment is financed via a mix of reserves as well as local/ regional/ national/ EU funding and includes an increase of the monthly rent from 4.38 €/m²*month to 4.71 €/m²*month whilst reducing the average charge for operation, maintenance and other running costs from 1.25 €/m²*month down to 0.85 €/m²*month.
Roof to wall insertion section (thermal bridge)
Insulation of the attic floor by using 20 cm EPS in addition to the existing 10cm.
Ground to wall section (thermal bridge)
Additional thermal insulation of the lowest storey ceiling of 17.5cm Tektalan
Wall to fenestration section (thermal bridge)
Mechanical ventilation: 3 centralised ventilation systems are implemented and connected to 31% of the building users. All other apartments will be upgraded on long-term.
Electric renewable integration
Nominal power of PV IN 28: 41,08 kWp
Mounting type: Roof mounted parallel
Elevation: 574 m a.s.l.
Azimuth angle: 248 °/126°
Financial model: Feed-in-tariff
Nominal power of Fennerstraße: 27,82 kWp
PV array area: 178 m²
Module type: Solarwatt Blue 60 P, 260 W
Inverter type: 1 x Fronius Symo 20.0-3-M
1 x Fronius Symo 8.2-3-M
Nominal power of Oswald-Redlich-Str.: 13,26 kWp
PV array area: 84,8 m²
Module type: Solarwatt Blue 60 P, 260 W
Inverter type: 1 x Fronius Symo 12.5-3-M
Contracting authority: NHT Neue Heimat Tirol
Project manager: Gerda Maria Embacher
Architect/Envelope Designer: Architekt Vogl-Fernheim
Technical system designer: Fa. Klimatherm, Zirl (HKSL), Fa. Obwieser, Absam (ELO)
Construction company: Fa. Bodner
Windows supplier: Fa. Alutherm, Innsbruck
Safety supervisor: Kopecky Karin
Carpenter: Hutter und Söhne, Innsbruck
Energy consultant, scientific support: University of Innsbruck and Passive House Institute – Department Innsbruck
Total investment of app. € 2,5 Mio.
The challenges in the course of the refurbishment of residential buildings are complex and multi-layered. Financial and social aspects and challenges need to be considered, because the tenant has to co-finance some parts of the renovation, which requires the implementation of persuasion and tenant engagement activities. Furthermore, legal challenges also have to be solved. The most intensive persuasion is to be done in the field of nearly zero energy house renovation and especially in cases where tenants are living in the flats during the time of ventilation system installations and other intrusive renovation activities.
Renewable energy sources
Prognosis of the yearly yield: 43,755 kWh/a
End-Energy use (EPC): See calculated values above
Energy efficiency certificate (EPC)
EnerPHit pre-certificate for stepwise refurbishment (PHI)