Over a century ago, Vienna embraced a truth that many cities still struggle to accept – that high-quality affordable housing is the stable foundation on which social cohesion and quality of life are built. In 1919, reeling from the collapse of the Habsburg Empire and a dire housing crisis, Vienna started levying high taxes on luxury goods and consumption, using the money to build so-called community buildings (Gemeindebauten) for the working class. This kickstarted the city’s public housing system, which is now widely considered one of the best in the world.       

Four hundred Gemeindebauten, with 64,000 apartments in total, were built in the first construction push between 1923 and 1934. Today Vienna is Europe’s largest home-owning city, renting out 220,000 social apartments to 500,000 residents – a quarter of the city’s population. Once the roughly 200,000 cooperatively owned apartments built with municipal subsidies by Limited-Profit Housing Associations (LPHAs) are added into the mix, 60 per cent of Viennese live in government-subsidised housing. This has a dampening effect on rent prices in the private sector: according to a 2023 study, average rents in Vienna are 35 per cent lower than in Brussels and a whopping 68 per cent lower than in Paris.  

Now Vienna is gearing up to tackle a new challenge: meeting its goal of climate neutrality by 2040 while continuing to provide a high quality of life and affordable housing to its population, one of the fastest growing of all European cities. It’s a massive undertaking, but a crucial one: globally, buildings account for 39 per cent of carbon emissions, so decarbonising the housing sector is considered one of the most cost-effective ways to mitigate the climate crisis. 

Renovating and decarbonising existing buildings is also a key initiative of the European Green Deal, but with so many cities already struggling with rising housing costs there is well-founded concern that such renovations will further drive up rents and exacerbate the housing crisis. The cost of renovation can be passed onto the tenants in 21 European countries, and low-income people are most likely to live in old, energy-efficient housing. With a strong grip on the city’s housing market and a century-long social housing tradition to build on, Vienna is in a better position than most cities to implement a future-oriented affordable housing model.  

Light, air, sun – and green energy 

In 2020, the city government – a social-liberal coalition – anchored its commitment to reach climate neutrality by 2040 in the Government Agreement, which includes a section on “affordable living of the future”. The strategy is two-fold: refurbish existing buildings to lower their energy consumption and decarbonise their energy sources, and build new affordable housing according to strict environmental criteria. 

Not only has Vienna never sold off its municipal housing (unlike many other cities); it also continues to expand its social housing stock. After a decade-long break in building new Gemeindebauten, construction recommenced in 2015, with the city aiming for 5500 new social apartments by 2025. But now, the age-old guiding principle of providing tenants with “light, air and sun” is accompanied by close scrutiny of the building’s environmental impacts. 

“When we think of the Gemeindebauten in Vienna, they have been here for over 100 years, and this is how we have to think about the buildings we build now,” says Silvia Hofer, who oversees new construction at the Vienna Housing Fund (Wohnfonds Wien). “If they are to be sustainable for the future, we have to think of climate change, and they have to be adaptable. We also have to think of the grey energy in the materials we use, how much CO2 is released in the construction and how much in the use of the building.”  

High-quality affordable housing is the stable foundation on which social cohesion and quality of life are built.

Wohnfonds was created in 1984 as the Vienna Land Procurement and Urban Renewal Fund to supervise the restoration of old buildings and to stockpile land for social housing. It currently holds 3.2 million square metres of land reserves – another ace card that helps the city to control development – and oversees new construction and restoration of affordable housing, coordinating between municipal departments, property developers, and service centres of the municipality of Vienna. In 2018 the city introduced the “Subsidised Housing” zoning category, in which new developments with more than 5000 square metres of living space have to allocate two-thirds of usable floor space for affordable apartments (this includes co-ops). Every subsidised housing project must adhere to the “four pillar model” of the Wohnfonds, which includes strict social, economic, architectural and ecological factors.  

“Of course, we want to have the best housing projects, like we have for over 100 years,” says Hofer. “But we also have to think about energy consumption overall – when we build it, when we use it, and how we can reduce, reduce, reduce. This is something that really drives us to have new ideas, to have new materials and new techniques, to try everything for a better environment.” 

New buildings have green and well-insulated facades that lower energy consumption and protect residents from extreme temperatures. They depend on heat pumps, district heating and solar panels for their energy needs. Adaptability of use is also key: in a recently completed Gemeindebau in Seestadt, a large new urban development that doubles as the city’s testing facility for sustainability projects and Smart City best practices, sliding walls make it easy to change the apartments’ layout, creating home offices, guest rooms or nurseries as needed.  

Crucially, the buildings are designed to create community and support sustainable lifestyle choices. Beyond the traditional leafy courtyards and laundry rooms that are the hallmark of old Viennese Gemeindebauten, the new ones include community rooms, gardens and rooftop terraces. Living in a smaller apartment – fundamentally the more sustainable choice – doesn’t feel cramped when you can always use the shared facilities to throw a birthday party, meet up with friends for a rooftop drink or grow vegetables with your neighbours.  

These communal resources also make life easier for especially vulnerable people, like single parents or the elderly. “You need communal rooms where somebody can keep an eye on your kid – for example, when you have a doctor’s appointment,” explains Hofer. “And of course, you need neighbours that are willing to do that. So we really do a lot of community building.”  

Deep energy retrofit 

Strong communities will play a crucial role in future climate resilience, and this thinking is part of the focus on social sustainability. Wohnpartner, a service of the city of Vienna, supports residents of Gemeindebauten in all aspects of community building, from connecting local initiatives, running neighbourhood centres and organising community events, to facilitating conflict resolution among neighbours and peer mediation trainings in local schools.  

In order to increase living space without turning the city into a concrete jungle, a lot of new construction is also happening on top of existing social housing as part of the city’s gentle re-densification effort. In Gregorygasse on the western outskirts of Vienna, a blocky 1960s Gemeindebau is getting 44 new attic apartments with terraces – part of the 834 attic apartments that have been built since 2015. The new apartments are made with prefabricated wooden elements to reduce their environmental impact and construction time. In addition to getting a whole new floor, the old part of the building will be kitted out with 18 centimetres of additional insulation, new windows and basement ceilings, lowering the building’s energy needs by 87 per cent.  

This kind of “deep energy retrofit” of residential properties has the potential to reduce the housing sector’s carbon emissions by as much as 51 per cent when implemented on a large scale. There are currently around 80 retrofitting and refurbishment projects underway in Viennese Gemeindebauten, with an investment volume of some 800 million euros. In addition to renovations and decarbonisations, some of the buildings have also had solar panels installed on the roof, which feed energy back into the city’s grid. So far, 10 rooftop photovoltaic systems have been set up with a combined area of 6000 square metres, and in one of the city’s largest municipal buildings, Hugo-Breitner-Hof, a solar thermal system supplies over 2000 residents with hot water.  

In addition to reducing the energy consumption of existing housing stock, a large part of the effort is in ensuring that remaining energy needs are covered through sustainable sources. While most social housing is already connected to district heating, around 95,000 apartments still depend on gas for their heating, hot water or cooking, and 1400 buildings have to be transitioned to new energy sources by 2040. The city-wide “Raus aus Gas” (Out of Gas) campaign aims to phase out gas by 2040 – but many renters are reluctant to put up with the hassle this would entail.  

Strong communities will play a crucial role in future climate resilience.

“We know how a thermal pump works and where to put it. We know how to connect a building to district heating. Our biggest challenge is getting the tenants on board,” says Daniela Cochlar, who is leading the project for Wiener Wohnen, which manages the city-owned social housing. The city has free reign in decarbonising the public-facing parts of its buildings, but needs the renters’ permission to do the necessary construction work in their apartments. This can make or break a project – an air-to-water heat pump is of little use if no apartments are connected to it, and district heating will only supply a building if 80 per cent of the apartments sign up to use it. For many tenants, especially the older ones, the idea of having construction work done in their apartments and changing the way they have always done things is daunting.   

“It’s understandable – it’s a major intrusion in a very private sphere,” says Cochlar. “The tenants aren’t against our ideas. They generally also understand that we have to do our part for the climate and the environment, and the cost is not the biggest issue either, which surprised me. The biggest concern is this intrusion into their private lives, into their private rooms, and that it will be an inconvenience.”  

To what extent the costs of the upgrade fall to the tenant depends on a number of factors, but the city has already developed various models for tenants to pay in small monthly instalments, which would be largely offset by the lower heating bill. Since March 2024, residents can also apply for a decarbonisation premium and receive between 1000 and 1500 euros from the city to help cover the cost of phasing out gas in their apartment or house. This has already spurred a lot of interest from tenants, says Cochlar. 

Unlike Germany’s controversial Buildings Energy Act, which came into force in January 2024 and inadvertently fuelled the right-wing AfD’s popularity, Vienna’s ambitious plan to phase out gas hasn’t so far ruffled any feathers. In a city where the socialist democrats have been in power continuously since 1945 and so many residents live in city-owned housing, not to mention the city’s ongoing ranking as the most liveable city in the world, there is a certain trust in the city’s plan for the future. Besides, change is coming slowly, and care is taken to ensure that no one feels blindsided. “Raus aus Gas”, for instance, will remain in a pilot phase until 2026, and the city is testing different approaches on a handful of Gemeindebauten before a full-scale rollout.  

Clear communication 

Much of the work goes towards trying out different communication strategies and convincing tenants that the inconvenience will be worth it in the long term. At Deutschordenstrasse, where two 1950s buildings are currently being converted to a geothermal heat supply, the city set up an information point where tenants can get information, ask questions and even test out different electric stoves. “It’s important to meet people where they are, be there in person and allay any fears,” says Cochlar. “Then a lot is possible. We’re learning a lot about what works and what doesn’t.” 

Nicole Büchl, head of renovations at the Wohnfonds, also sees this sustainable transition in the housing sector primarily as a communication challenge. There needs to be more awareness around energy consumption, she says, with people developing a deeper understanding of it. “What needs more energy, what needs less energy?” she asks. “It’s important to get a feeling for it.”  

Vienna will have to overcome many hurdles – some expected, many unforeseen – if it wants to meet its goal of climate neutrality by 2040. But the important first step has already been made: the understanding that such a transition is not possible without tackling head-first the immense environmental impact of the housing sector, while ensuring that the burden of the effort is not passed down to the city’s residents. “We really strongly believe that social housing is part of being a sustainable city,” concludes Hofer.