Renovation of the "Gründerzeit" building Eberlgasse in passive house standard
The demo-project is situated in the „Alliiertenviertel“ of Vienna`s second district. Built in 1888 the building represents a typical Viennese „Gründerzeithaus“reflecting the city`s changing history.
In 1944 it was expropriated by the Nazi`s from the legal owners, a young married couple named Fiala. The couple already fled in 1938 to South America and became the only members of their family to survive. In April 1945 three bombs struck the building, causing immense damage.
The property, including the damaged building, was returned to the Fiala family in 1948. The renovation of the damaged building was completed in 1952 but the former neo-classical facade was not reconstructed. During the following decades the maintenance of the building was neglected, leading to an investment backlog in 2009, when the renovations planning process began.
The situation before the renovation was characterized by a lack of accessibility for people with disabilities, outdated utility lines, high heat energy consumption, no modern standard of living as well as a leaking roof.
Motivation and Objectives
The aim of the renovation was to improve tenants living standards and to achieve the Passive House Standard for the first time in history with a “Gründerzeit” bulding that is occupied during the refurbishment.In addition of achieving the Passive House Standard, another primary goal of the project was to dramatically reduce the primary energy demand.
The basic concept of the Eberlgasse renovations included:
- a detailed current state analysis of the building,
- an energy strategy analysis that explored a variety of options such as community-heating, wood pellets and geothermal energy usage, resulted in an ideal solution of combining a groundwater heat pump with solar panels,
- based on the status analysis and the energy strategy an experienced planning team defined insulation thickness, thermal quality requirements for windows and doors, system requirements of the building services etc.,
- the inclusion of tenants in the planning process and ongoing assistance during the construction period.
Results / Suggestions for future research
The passive-house renovation Eberlgasse meets all „EnerPHit“ criteria for passive house renovations in compliance with the Passive House Institute. According to PHPP calculations, a calculated heating demand of 14,8 kWh/(m²EBF.a), a primary energy demand of 108 kWh/(m²EBF.a) and a heat load of 9,1 W/m²EBF even meet the more stringent passive house requirements for new buildings in compliance with the Passive House Institute.
Major contributing factors for success were the detailed current state analysis, the experienced planning team and the appropriate inclusion of tenants. A restoration process of a partially inhabited building requires a detailed coordination and time scheduling.
From a technical perspective the most challenging objectives to achieve were the subsequent installation of a ventilation system with heat recovery, the airtight surface of the building as well as reducing thermal bridges.
The integrated approach to reduced primary energy consumption led to the following additional investments:
- new kitchens equipped with the most energy efficient kitchen appliances,
- indoor and outdoor LED lighting system,
- energy recovery system for the vertical elevator.
The additional costs of the renovation to the Passive House Standard compared to conventional renovation amount to 266 Euros/m²WNF.
Andreas Kronberger Unternehmensberatung
Schöberl & Pöll GmbH