The Budapest Housing Stocktaking
- the building typology of the Hungarian capital

The housing stock in Budapest comprises almost 201,000 buildings, totalling 961,061 apartments. To get an accurate picture of what these buildings are like from their energy performance; what kind of flats they are, what they are made of and how thick their walls are, what their windows are like, someone would have to walk around the city, knock on every door, take precise notes and summarise the results. All this almost a million times. But what if no one is at home? Or the owner doesn't want to let the surveyor in? But do we even have that many technicians and, above all, that much time? It is easy to see that this would be an unrealistic undertaking. Dr. Bálint Hartmann, senior researcher at F4STER and his team supported by Tamas Csoknyai have taken an approach to replace all this work by clustering residential buildings into 32 categories.

In Budapest, more than 200,000 residential buildings are home to nearly one million apartments. And most of them could benefit from an energy retrofit.

Their work was carried out in the framework of the Budapest CARES project with the aim of grouping residential buildings in Budapest in order to be able to see the potential energy saving as well as the corresponding CO2 reduction. The extent to which a given type of building can be improved in terms of energy efficiency and the amount of money that can be invested in interventions can all be examined based on these types.
Overall, this is important in order to be able to carry out a more efficient “future-proof” redesign of the multi-apartment buildings in Budapest. With a better understanding of exactly what kind of buildings are in Budapest, we can plan more accurate and efficient renovation programmes, so that climate and environmental goals as well as occupant satisfaction can be more easily achieved. The typology and the attached energy/CO2 reduction potential can be considered as a decision support tool, which helps to prioritise buildings according to a number of criteria, so that they can be ranked, such as the greatest energy savings per unit cost. This is a great help when making policy decisions: instead of cautious attention to district boundaries and municipal commitments, it allows focusing on objective technical parameters of the buildings and the social and financial situation of the occupants can be added on top.

Using this typology, the carbon footprint of the capital's residential buildings can be assessed to optimize renovation and energy efficiency programmes for the buildings most in need of energy renovation and to reach the largest number of occupants. This will ensure that the available budget is spent in a targeted and efficient way.
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The Budapest Housing Stocktaking provides a wealth of lessons. The figure below shows interesting data, such as the fact that the capital has 1,700 adobe houses, but only half as many were built after 2018, so very few residential buildings can be considered young and up to the standard. It is easy to see that in the first half of the 20th century, a lot of residential buildings were erected as the city grew larger. Then the 1960s brought the Kádár cubes, and almost as many of these were built as during the family house trend of the 1980s and 1990s.

What (old) buildings do we live in?

Residential buildings in Budapest can be categorised by construction period. There are four “age groups” with different structural and energetic characteristics, and the age of a building has a significant impact on its energy efficiency and renovation potential. Old buildings (before 1900): solid masonry, high ceilings, low insulation value. These are well-known houses within the city centre, where thick walls keep the heat relatively well inside in winter and cool in summer, although the high ceilings make them very energy-intensive to heat.

The city centre is home to a number of old “bourgeois” buildings, richly decorated with exciting ornaments. They are typically of thick masonry but with large, perhaps too high ceilings.

Panel houses built between 1960-1990: Every fourth family lives in such a building in Budapest. Reinforced concrete structures, prefabricated concrete panels, with a very low ceiling and better, but still low energy efficiency. It certainly represents high renovation needs. These buildings come with much smaller floor areas and uniform flats. Since such buildings are easier to insulate than a fancy old bourgeois-like building, and there are many prefabricated and prefab-like residential buildings built with slightly different technologies in the capital, it makes sense to focus the first pilot phase of the energy renovation programme on these buildings.

There are also loads of non-ornamented, smaller buildings on the way to the suburbs.

The well-known industrialised housing estate with its prefabricated buildings is ideal for energy efficiency renovations.

Homes built after 2000: modern technologies, better insulation, lower energy consumption. Such buildings are built with a different approach. Many of them were specially built with good insulation, efficient heating systems, in some cases with central cooling and even accessible by design.

The younger houses already have many modern energy features: quality insulation, modern windows and doors and are accessible.

Where we have work to do: the prefabricated houses!

In Budapest, 22.1% of all apartments are in prefabricated multi-apartment buildings. By concentrating on this type of building, we can achieve a large number of apartments with relatively few projects, and since prefabricated buildings are often similar in design and in many cases used the same architectural plan - think of the repetitive buildings in housing estates - it is easier to define the needed improvements and energy renovation could be much faster and more cost-effective. Since the replication potential for renovation is high - if for example 6, 8, 10 and 12 Kossuth Street are architecturally the same buildings - the experience of number six will speed up the work for the other three buildings. Such renovated buildings are visually striking and can inspire neighbouring communities, increasing overall motivation to undertake similar improvements.