Innsbruck is one of the pilot cities of the FP7 project SINFONIA, and selected its eastern district to demonstrate the large scale implementation of energy efficient measures, with the objective of achieving on average 40 – 50% primary energy savings in the demo sites and to increase at least by 30% the share of renewables in the district’s energy mix.
The demonstration building (named IN28) consist of two residential blocks in Innsbruck all built in the second half of the 20th century. The scope of the building renovation is to increase the energy efficiency and to improve the indoor comfort of the apartments.
The interventions included both process and technical innovations (e.g. tenants involvement process, implementation of ventilation system, insulation, PV on the rooftop, etc.).
IN28 is a typical building block constructed in the second half of the 20th century with related challenges with regards to insulation, electric cables, low performing windows, non-insulated roofs and cellars, etc.
The overall gross surface, distributed in 84 apartments is around 7000 m2, with a heated volume of around 7700 m3. The technical system is decentralised, with all the apartments equipped with a single boiler for heating and domestic hot water production.
The primary energy need of the existing building accounts for 211 kWh/m2*a, while the energy target after renovation is 72 kWh/m²*a.
To reach that target, the renovation concept is mainly based on the thermal insulation of the envelope with:
- Thermal renovation of the walls, the ceiling, the roof and the windows
- Elimination of thermal bridges of the balconies
- Insulation of the attics
Moreover, further technical solutions include
- partial installation of new gas boilers.
- Variable air volume controlled central ventilation system placed in the cold attic.
- Domestic hot water production via electric de-central water heater
- New LED lighting in common areas.
- A photovoltaic system will be installed as a full feed system, so that the generated energy will be feed in the public grid and get the power compensated by the Austrian agency for green electricity.
In particular, the windows have been replaced with triple glazing systems and the façade insulated with 22 cm of EPS, with a focus on the elimination of thermal bridges due to balconies.
Moreover, the attic have been insulated by adding 20 cm of EPS to the existing 10 cm.
The reduction of the thermal energy demand is also coupled with the integration of renewable energy sources. In fact, 41 kWp of photovoltaic panels have been installed on the roof and the produced energy will be exploited with the feed-in tariff.
IN28 is owned by New Home Tyrol and rented at favourable lease, and the intervention have been financed by NHT, but the renovation lead to a slight increase of the monthly rate.
Therefore, in addition to the technical details, it is important to underline as a key point the active involvement of the users that have been engaged in the renovation and educated to the use of innovative technologies, in particular to the mechanical ventilation system.
At the end of the renovation, it has been observed a good level of satisfaction of the tenants and of the building owner.
If you are interested in having more information, please visit the project webpage: Here