Office Building B with a leasable area of 14,600 sqm and 1,250 sqm of retail space was built in 1999 by the Passerinvest Group in the Brumlovka mixed-use complex. The building revitalisation and other modifications in its immediate vicinity were finished in 2020. The building today meets the standards of the category B energy label.

As part of the reconstruction work on the building's facades and roofs, the building underwent fundamental changes to the blue-green infrastructure: planting of greenery on the building structures, roof gardens and water features were built around the building, including a rainwater collecting tank.

In 2022 Passerinvest also focused on further optimising the operation of ventilation, heating and cooling technologies such as setting algorithms for controlling the operation of the HVAC units according to occupancy, multiple resets of the manual setting of the room controls, and adjusting the central temperature according to seasonality. The result was a saving of 875 GJ compared to 2022 and 2023, i.e. a reduction in heat consumption by 23.7%. Compared to the previous year, in 2023 it was possible to reduce the consumption of electricity, heat and thus CO2 emissions even more.

Thanks to measuring the consumption of all energies before and after the renovation, it is now possible to calculate exactly how much savings have been achieved. The building's electricity consumption was reduced by approximately 50% (2018 vs. 2023) with the renovation and subsequent optimisation of technology operation, and the carbon footprint of the consumed electricity and heat was reduced by 65% compared to the original state.

An analysis of mixed municipal waste in May 2023 revealed a large proportion of sanitary paper towels, which reached a monthly volume of 13.4 cubic metres. A press for hygienic material reduced this volume by 17 containers each of 1,100 l per month. Compressed towels are also taken back by the manufacturer of hygiene products.