This research concentrates on creating wellbeing by performance; behaviour and technical performance of materials and products in office buildings. This research is focused on the case study conducted at; the headquarter of a bank in the Netherlands, whereby the building users are criticizing the indoor comfort. Moreover, the building materials are end-of-life and the building is using a large amount of energy. The following research question is answered: ‘How can the indoor comfort be improved in a circular way, by creating an optimal floorplan including the interior and technical aspects for, the case study, one pilot floor of the headquarter of a bank in the Netherlands, while taking the energy consumption into account?’ Within this study different research methodologies are applied. The first research method is literature study and reference projects to gather knowledge about the indoor comfort with the following possible stressors; indoor air quality, thermal comfort, light and visual quality and acoustic comfort and circularity within the building environment. This information is derived from the Dutch regulations, certification rating systems, the case study and articles with the same theme. The literature study and reference projects are analysed to draw up criteria which the measurements and the design of the floorplan must meet. The second research method is material analyses to identify the materials and products which are used in the interior of the case study and how they can be improved to contribute to the indoor comfort, circularity and energy efficiency. The third research method is analysing the existing survey conducted in 2019 by the company Leesman. Analysing this survey can profile the building users and rate the satisfaction level of their workplace, activities, and facilities. The last research method is analysing the performed measurements. To study the current situation of the case study by testing the indoor comfort stressors on the criteria prepared with literature study and reference projects. These measurements are performed with 24 GreenMe cubes which records the indoor comfort values every ten minutes for three weeks, which resulted in 3024 measurement points within ten categories of the indoor comfort stressors. The research results are translated into a circular and indoor comfort framework and floorplan design including the interior and technical aspects. The analyses results show that it is desired to renovate the headquarter of the bank in the Netherlands. This conclusion is based on the following results of this study, first of all most of the materials and products are not demountable. Therefore it cannot be cleaned well and it pollutes the air. Moreover, it is not fully circular when only the materials are obtained sustainable, but cannot be reused or remanufactured after its first lifecycle, when they are not demountable or additives are added. Secondly, the building users are not satisfied with the indoor comfort within the headquarter of the bank. According to the satisfaction and importance level of the indoor comfort stressors. The indoor air was rated with 28,6% satisfaction and 71% importance, thermal comfort with 19,1% satisfaction and 80,7% importance and acoustic comfort with 13,9% satisfaction and 75,1% importance. These results show a low satisfaction level, while the building users rated these facilities as very important. Furthermore, the measurements results show that the indoor comfort stressors exceed the permitted values during office hours. The carbon dioxide concentration is measured 1,7% above 800 ppm, total volatile organic compounds is measured 0% above 120 ppm. In addition, the temperature under 20°C and above 24°C is measured 10,5% and the relative humidity under 30% and above 70% is measured 14,6%. Moreover, the light level under 500 lux is measured 72,2% and flicker light under 0Hz and above 50Hz is measured 2,6%. Lastly, the average background sound level above 57dB is measured 2% and average installation sound level above 35dB is 0%. These values needs to be improved according the program of requirements of the case study. The analyses emphasize the importance of the renovation of the case study. Measures are recommended to improve these values. The measures have been compiled on the basis of the circular and indoor comfort framework and the developed ‘Circular Indoor Comfort Step Strategy’. This strategy is as follows: 1) Improving the source 2) Improving situation without energy 3) Improving situation with renewable energy 4) Improving processes The measures are categorized in interior aspects, improving the building users activities, and technical aspects, improving the indoor comfort stressors. Every measure contributes to the environment and supports the wellbeing of the building users. One of these measures is a green wall, which is mostly composed from raw materials from biological cycles and contributes to the mental state of the building users. Moreover, it improves the indoor air by filtering the air, thermal comfort by increasing the relative humidity, and the acoustic comfort by absorbing background sound. This product is sold as ‘product as a service’, whereas the producer keeps the responsibility and reuse every part after its first lifecycle to new products with the existing raw materials. This research shows that a big difference can be made by performing small interventions to maintain the current situation and increase the existing value. Moreover, these interventions have a positive influence on the satisfaction level of the building users, meeting the Dutch and the bank’s regulations and rating certificates to renovate and create a healthy circular headquarter.