The property at Mehringdamm 44–46 is a listed apartment building dating from 1868 in Berlin's Kreuzberg district. The aim of the project is to renovate the building to improve its energy efficiency in compliance with the requirements for listed buildings and to make structured use of subsidies for individual measures.
By switching from 20 decentralized gas boilers to a central hybrid heat pump in combination with photovoltaics, final energy consumption is reduced by 50% and the energy efficiency class is improved from G to D.
Purpose Green provides expert support for energy-efficient renovation projects with a high level of technical expertise. The combination of precise energy planning, reliable quality assurance, and a clearly structured subsidy strategy is particularly beneficial for the project. The advice provided is always transparent, legally compliant, and economically oriented, especially when it comes to the successful integration of subsidy programs.
Purpose Green provides expert support for energy-efficient renovation projects with a high level of technical expertise. The combination of precise energy planning, reliable quality assurance, and a clearly structured subsidy strategy is particularly beneficial for the project. The advice provided is always transparent, legally compliant, and economically oriented, especially when it comes to the successful integration of subsidy programs.
The building comprises 20 residential units and 4 commercial units with a total usable floor space of 2,000 m². Before the project began, the energy efficiency class was G with a final energy demand of 233 kWh/(m²a).
Heat was supplied via 20 decentralized gas-fired floor heating systems. This structure resulted in high primary energy consumption and significant CO₂ emissions. Under the statutory CO₂ cost allocation scheme, 95% of the CO₂ costs were borne by the owners.
In addition, the building is subject to strict historic preservation regulations, particularly with regard to the facade design and the windows facing the street.
The energy-efficient modernization of a historic building requires careful consideration of the balance between preserving the building's substance, energy efficiency, and eligibility for subsidies.
The main challenges were:
The conflicting goals of technical feasibility, funding logic, and grandfathering made an interdisciplinary approach necessary.
An integrated solution was developed to meet the technical, regulatory, and economic requirements, systematically linking analysis, planning, promotion, and implementation.
Purpose Green took over:
The detailed renovation plan developed by Purpose Green resulted in numerous positive energy, economic, and regulatory effects for the owner:
Stella Partners is an owner-managed real estate company based in Berlin and the Rhineland. The company specializes in the development and renovation of existing properties in inner-city residential areas and combines active portfolio expansion with the implementation of challenging construction projects for external partners.As a general contractor, Stella provides comprehensive support for real estate projects—from initial planning and obtaining building permits to construction and leasing or sale. This integrated approach makes it possible to control quality, costs, and schedules from a single source. The current development volume is around €75 million on a projected area of over 20,000 m².
