Can UK net zero-carbon building standards revolutionise how we define sustainable buildings?

As Net Zero becomes one of the most used and misused terms in real estate, the UK has introduced a rigorous new framework that could change everything. Here is what it means for markets like Poland.

“Get ready for Net-Zero Energy Buildings.” “Net Zero Ready – the first piece of the puzzle.” “The power of zero: a real-world net-zero office.” “The first skyscraper with zero net emissions is…” These are some headlines built around the concept of Net Zero Carbon buildings. They reflect the direction markets have been moving for years; yet many of these claims remain vague, difficult to verify, and are potentially misleading. Examples of loosely defined sustainability claims, unclear labels like ‘Net-Zero Ready’, standard technical solutions presented as exceptional achievements, or buildings called “sustainable” with no measurable evidence of operational performance are still common across the market. Poland is no exception.

When ‘green claims’ stop being enough
Sustainability, energy efficiency, and environmental performance in the building industry have become increasingly important to investors, developers, financial institutions and occupiers. In the past, broad and unverified ‘green claims could even deliver significant short-term commercial benefits.

However, that era is coming to an end. As market awareness grows, companies relying on exaggerated environmental messaging face pressure to back up their claims with evidence. The absence of credible data can lead to reputational damage, tangible financial and regulatory consequences. Industry experts are becoming far more cautious in the way they communicate any sustainability commitments, placing greater emphasis on transparency, verifiable data, and evidence-based reporting. Despite this shift, the industry still lacks a widely recognised definition of what ‘Net Zero Carbon’ actually means, or even how a truly sustainable building should be defined.

The Polish context: certification and its limits
In Poland, these concepts are often closely associated – if not treated as synonymous – with multi-criteria certification schemes. According to the PLGBC report Sustainable Certified Buildings 2026, 99% of modern office buildings in Poland are certified. Over the past decade, certified floor-area overall has grown from around 6.8 million m² in 2016 to more than 57.5 million m². This extraordinary expansion was driven mainly by BREEAM, LEED and WELL.

For many years, achieving certification at an appropriate rating level was effectively regarded as proof that a building was sustainable. Polish building regulations have reinforced this trend, progressively tightening requirements related to building envelope performance or Primary Energy Demand. A proposed regulatory update (planned for full introduction by end of 2026) includes for the first time, definitions of both low-energy and zero-emission buildings.

Five cracks in the current framework
There are several important pitfalls to consider when defining a ‘sustainable building’ as presented above:

• Sustainability claims often focus on operational emissions, without addressing how energy demand itself is reduced. As a result, Energy Use Intensity (EUI) targets or achieved performance levels are rarely disclosed. Instead, buildings rely on renewable energy offsets regardless of their actual consumption levels.
• Whole-life carbon is largely ignored. Communication concentrates on operational carbon while overlooking emissions from material production, construction, maintenance, replacement and end-of-life deconstruction.
• ‘100% renewable energy’ can mislead. In many cases, this applies only to electricity, which is straightforward to offset. Buildings connected to district heating systems, which in Poland still rely on a mix of fossil and non-fossil sources, are rarely addressed with the same rigour.
• Certifications don’t expire. BREEAM or LEED confirms that the design and construction process followed recognised sustainability guidelines. Awarded at completion, these certificates remain valid indefinitely. Many were issued over a decade ago. This raises an important question: can we still assume that these assets operate in line with their original design intent? Without ongoing performance verification, or mechanisms requiring disclosure of operational metrics such as energy, water, or waste performance, such certifications lose relevance over time.
• Operational certifications are underused. In practice, BREEAM In-Use in Poland often covers only partial verification, largely based on design and as-built documentation rather than measured operational data. Meanwhile, LEED Operations and Maintenance has seen only 14 certifications in Poland over the last five years.
• Proposed Polish building regulations define low-energy and zero-emission buildings through the Primary Energy Demand indicator included in Energy Performance Certificates (EPCs). This approach excludes embodied carbon and broader whole-life emissions. Moreover, EPC methodologies were never intended to reflect actual operational performance; rather, they estimate the theoretical efficiency potential of building HVAC and lighting systems under standardised conditions. Based on such reference, it is hard to consider real operational impacts.

What the UK is doing differently
The industry is recognising these limitations, particularly the disconnect between design-stage commitments and the verification and disclosure of in-use performance. In this context, the UK provides a compelling example of the shift from a design-led approach towards one focused on measurable operational performance. Declarations alone are no longer considered sufficient; instead, sustainability is becoming re-defined through transparent, evidence-based methodologies and verified performance data.

An important milestone in this transition was the introduction of NABERS UK in 2020. This performance-based rating system measures building energy efficiency entirely through verified operational data.

The most significant step came in March 2026, with the launch of Version 1 of the UK Net Zero Carbon Buildings Standard.

What is the UK NZC Building Standard?
Developed through collaboration with more than 350 industry experts and consultation with over 700 stakeholders, the standard establishes a unified, industry-backed methodology for measuring operational and embodied carbon emissions in new and existing buildings. It provides clear, science-based methodology and definitions of net zero aligned with the UK’s 2050 climate objectives. It is voluntary and applicable to new developments, existing buildings, and retrofit projects. What distinguishes the standard from approaches commonly seen in the local market is its emphasis on measurable performance rather than design intent alone. Key principles include:

• Clear and ambitious Energy Use Intensity (EUI) targets for different building typologies, which must be achieved before renewable energy offsetting can even be considered. This places energy demand reduction at the core of net-zero design.
• Mandatory targets for upfront embodied carbon.
• Consideration of refrigerant impacts and fugitive emissions.
• Recognition of all energy sources, with a focus on eliminating direct fossil fuel use on site.
• A requirement for at least 12 months of measured operational data following occupation.
• Independent third-party verification based on actual performance data, not design-stage assumptions.
• Expected annual recertification to ensure continued compliance over time.
• Mandatory disclosure of lifecycle embodied carbon, operational energy and water consumption, as well as energy procurement and offsetting strategies.

The standard also provides policymakers, investors, insurers, and industry leaders with greater clarity regarding the actions required to meet national carbon reduction targets.

Why this matters beyond the UK
As the industry becomes more aware of these interdependencies, financial institutions, insurers, regulators, and other stakeholders are following. Performance-based sustainability verification is highly likely to become an expected requirement rather than a market differentiator, driven by the need to improve investment resilience and reduce business risk.

While the UK is currently leading this transition, it is increasingly setting the direction for the wider European market and beyond. This proves that the future of sustainability in the built environment is moving away from declarations and towards transparent, measurable, and performance-driven outcomes. For markets like Poland, where certification culture is deeply embedded, the approach outlined in the standard offers both a challenge and an opportunity: to move from ticking boxes to demonstrating impact.