Currently, there is a major housing shortage and climate crisis. There is a shortage of housing for starters and singles, and the rental market is shrinking in the Netherlands. Residential buildings are often new construction, and their climate design needs to be energy efficient and sustainable. In addition, many cities face a surplus of vacant offices/premises. These office buildings can be transformed into residential buildings. This can accommodate a large circulation of housing and once the indoor climate is optimised, the building becomes much more sustainable. For the research, the thematic research question was formulated, focusing on thermal comfort as: “How can a climate system, for the benefit of vacant office buildings, be designed to provide optimal thermal comfort, be user-friendly and energy efficient, minimizing the cost to the residential building?”

The research includes an extensive literature review. This was done by reading books, (newspaper) articles, reports and theses. The literature review also provided some case studies. Furthermore, interviews were done with a renovation architect, property managers and building physicists. The interviewees also recommended several case studies.

The research shows that hybrid air-conditioning systems for transforming office buildings can create energy-efficient and comfortable homes. Combining passive and active techniques, such as insulation, shading and heat pumps, offers a flexible and efficient solution. Central ventilation systems are suitable for larger buildings, while decentralised systems such as the AEROMAT VT ventilation system are ideal for smaller buildings. When looking at costs that can be saved is by reducing heat loss, and to achieve this, the indoor climate must work as optimally as possible, and the thermal comfort must be as optimal as possible. To make it user-friendly, the operation of the systems and their use should be well communicated to occupants. This approach ensures optimal indoor climate with low operating costs and a sustainable home renovation.

It is therefore concluded that an integrated approach of passive and active techniques can provide an energy-efficient and comfortable indoor environment for the transformation of empty office buildings. Hybrid systems combine passive techniques such as insulation and use of thermal mass with active systems such as heat pumps and mechanical ventilation systems. At the same time, the use of sustainable materials reduces the ecological footprint. By reusing materials and applying circular design principles, the costs of future transformations are reduced. This makes transformation to housing economically and sustainably feasible.