The greatest lever isn’t the year of construction. It’s how existing buildings are managed.
This article puts into context:
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why ESG in office properties is not primarily a new-build topic
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how tenant, market and regulatory requirements interact
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why successful implementation depends on operational asset management
Most of the buildings that will still be in use in 2050 already exist – many of them constructed at a time when energy efficiency and climate risks played little role in planning decisions. Older office properties are coming under increasing pressure as a result: Regulatory requirements, changing user expectations and a market that clearly favours ESG‑compliant space are significantly raising the bar for existing assets.
Failure to act puts letting prospects at risk and can lead to gradual value erosion – in extreme cases up to the point where a property becomes unmarketable. What matters most, however, is not the year of construction, but a structured transformation process. In this context, operational asset management is the key lever.
Existing Office Buildings under ESG-Pressure
Many office buildings that are relevant today date back to periods when energy efficiency, digital infrastructure and climate risks were of secondary concern. Consequently, a large number of assets are in a condition that only partially meets future ESG requirements – whether due to energy-related deficiencies, outdated building services or limited flexibility of floor layouts.
At the same time, user requirements have changed significantly. Companies now scrutinise energy performance indicators, indoor climate and technical quality far more closely than just a few years ago. In many cases, existing offices can meet these requirements – but only through targeted, phased modernisation measures. With well-structured project management, technical and functional shortcomings can be addressed incrementally without the need for demolition.
ESG in existing buildings is therefore not an abstract obligation, but a question of economic viability and competitive positioning for each individual office property.
Regulatory and Market Drivers
As outlined in part 2 of this series, regulatory requirements are increasingly affecting existing properties, even if they are not directly subject to reporting obligations themselves. Banks, investors and insurers expect robust information on energy efficiency, emissions and climate risks and increasingly make this a prerequisite for financing, valuation and insurability.
This structural need for action is independent of political cycles. According to the ENOB:dataNWG study (IWU, 2022), the average annual modernisation rate of building envelopes in the non-residential segment most recently stood at around 0.7 per cent – well below the level required for a climate‑aligned modernisation program by 2045.1,2 The dena Building Report 2026 confirms that the building sector continues to miss its climate targets. 3
At national level, the German Building Energy Act (GEG) is set to undergo fundamental further development. On 24 February 2026, the Federal Government presented initial key points for a Building Modernisation Act (GModG). The aim is to create more reliable and practical framework conditions for investments in existing buildings. The focus is on technological openness in heating system replacement, long-term funding instruments and the transposition of the European Energy Performance of Buildings Directive (EPBD) into national law.
In our view, clear and long-term regulatory frameworks are a fundamental prerequisite for forward-looking investment decisions along decarbonisation pathways in existing assets. In this respect, the announced full implementation of the EPBD is the right and necessary step.
User Perspective: ESG as a Letting and Competitive Factor
Office user requirements have changed markedly in recent years. Today, ESG translates into concrete expectations regarding operating costs, space quality, technical specifications and sustainability transparency – and feeds directly into tenants’ own sustainability reporting.
Key topics include energy efficiency, adaptable floor plans, high-quality indoor climate and reliable digital infrastructure. ESG objectives are increasingly being anchored contractually: green lease clauses govern the exchange of consumption and emissions data, define shared sustainability targets and help reduce potential conflicts of interest between landlord and tenant.
The growing relevance of sustainability in day-to-day building operations is also reflected in formal market indicators. For example, the number of DGNB certifications for buildings in operation increased from 53 in 2020 to 193 in 2021 and 459 in 2022.
In this market environment, existing buildings can close the gap: Through targeted repositioning, phased modernisation and clear communication, they can be positioned as sustainable assets. The decisive factor is the ability of asset management to identify user requirements early, prioritise economically viable measures and implement them during ongoing operations.
ESG in Operational Asset Management – From Analysis to Implementation
The success of ESG transformation is decided at operational level. In existing assets, ESG is not a one-off project, but a continuous management process that integrates building data, technical systems, user requirements and strategic objectives.
The starting point is the systematic collection of building data. In many older office properties, data availability is incomplete. In our view, the goal is not immediate completeness, but reliable transparency: Which technical systems are in place? Which consumption data is available? Where are the gaps? On this basis, measures can be realistically prioritised, closely aligned with current and intended use of the building.
Implementation depends significantly on occupancy status: In occupied buildings, minimising disruption to tenants is top priority; in vacant properties, greater scope for action exists. In both cases, professional project management is essential, as well as transparent communication with owners, tenants and lenders.
How we support owners in ESG‑related transformation challenges is illustrated in our case studies.
Conclusion
The ESG transformation of existing office properties is not a “one-size-fits-all” task, and its economic effects cannot be generalised. Whether operating costs decrease or investments amortise quickly depends on the individual asset, its use and starting condition. What matters is a structured approach: a robust data basis, clearly prioritised measures, professional project management and transparent communication. Those who adopt this approach not only safeguard the future viability of their properties but also create the basis for well-informed investment decisions.
Which measures should realistically be prioritised for your office asset in this context? We would be pleased to discuss this with you.
1 Institut Wohnen und Umwelt (IWU): ENOB:dataNWG – Research Database for Non-Residential Buildings. Partial report „Stand und Dynamik der energetischen Modernisierung von Gebäudehülle und haustechnischen Anlagen“ (“Status and dynamics of the energy-related modernisation of building envelopes and building services systems”), 2022.
2 Classification: The ENOB:dataNWG study (IWU, 2022) itself does not define a specific target level. It states that the observed modernisation rate of around 0.7% per annum is significantly below the level required for a climate‑aligned development of the building stock by 2045. In transformation and scenario studies, a target corridor of around 2% annual modernisation rate or more is frequently assumed in order to achieve the climate targets in the building sector.
3 Deutsche Energie‑Agentur (dena): dena‑Gebäudereport 2026 – Zahlen, Daten, Fakten zum Klimaschutz im Gebäudebestand (Building Report 2026 – figures, data and facts on climate protection in the existing building stock), 2026. https://www.dena.de/infocenter/dena-gebaeudereport-2026/)
