Building standards: the CO₂ Performance Ladder vs BREEAM, LEED and Level(s)

When it comes to assessing and certifying the sustainability of buildings, several tools are widely used. Among the best known are BREEAM (Building Research Establishment Environmental Assessment Method) and LEED (Leadership in Energy and Environmental Design). In addition to these, there are regional and national initiatives such as Ireland’s Home Performance Index, Germany’s DGNB certificate, and the EU’s Level(s) framework.

These building standards are designed to evaluate the environmental performance of buildings and the built environment throughout their lifecycle. In this blog, we focus on three of the best-known systems: BREEAM, LEED and Level(s), and explore how they relate to the CO₂ Performance Ladder — a well-established system for reducing emissions in the construction sector.

So, how do these four systems work, and how do they compare?

Understanding the standards

What is BREEAM?

BREEAM is an international certification for specifying and measuring the sustainability of buildings. It can be used for new build, renovations, in-use buildings, and communities. There is also a BREEAM infrastructure standard. BREEAM covers a wide range of aspects of environmental performance, covering the whole lifecycle of the building from design  to use, based on a lifecycle analysis approach. Buildings can receive a range of ratings, from outstanding (85% plus of the standard achieved, 5 stars) to pass (30% and up, 1 star). BREEAM certification is carried out by a third party assessor and then checked by BRE Global Ltd. Fees for certification are calculated per metre squared, and so vary based on the size of project.

What is LEED?

LEED certification is a framework for sustainable buildings, covering environmental, social and governance aspects. Similar to BREEAM, LEED offers certifications for building design and construction, interior design and construction, operations management, and wider built environment standards for neighbourhoods and cities. LEED has 4 levels, from certified (40-49 points) to platinum (80+). The scheme is developed by the US Green Building Council and third-party verified by GBCI, a certification body established by USGBC. Certification costs depend on project size, complexity and the rating system used.

What is Level(s)?

Level(s) is a framework developed by the European Union to aid in improving the environmental performance of buildings. As such, it does not offer certification, but does have three levels, with level 1 focussing on the qualitative aspects of building design, level 2 addressing quantitative monitoring of design and construction, providing common units and methods to apply, while level 3 addresses the ongoing monitoring of building performance after completion. Level(s) is currently still voluntary but will be made mandatory in the EU for large new buildings from 2027, and all new buildings from 2030, as part of the Energy Performance of Buildings Directive (EPBD). Level(s) guidance is freely available online.

What is the Ladder?

The CO₂ Performance Ladder is a certification system that helps organisations reduce their CO₂ emissions and operate more sustainably. The Ladder consists of three steps, each reflecting a greater commitment to decarbonisation. Organisations choose their own ambition level and work progressively towards lower emissions and energy use.

• Step 1 focuses on improving internal operations, targeting reductions in energy use and Scope 1 and 2 emissions.
• Step 2 extends to the full value chain, requiring a climate transition plan (CTP) and active collaboration with partners.
• Step 3 aims for net zero across all scopes by 2050, with quantified long-term targets and deep reductions across the organisation and its chain.

Certification is carried out by independent accredited bodies. Costs depend on organisation size and include audit fees, implementation costs, and a turnover-based contribution to the scheme manager.

Similarities: where the Ladder and building standards align

The Ladder, BREEAM, LEED and Level(s) all aim to reduce carbon emissions in the building and infrastructure sectors. All of them apart from Level(s) work similarly in terms of the development and auditing of the standard, with multiple levels and external checks.

BREEAM, LEED and Level(s) can each be combined with the CO₂ Performance Ladder to highlight aspects relating to the reduction of CO₂ emissions in certified building projects. The Ladder provides a complementary framework for tracking and integrating these asset or project-related reductions into overall emissions management at an organisational level. The certification of buildings according to BREEAM, LEED or Level(s) can also be a measure to reduce emissions as part of the Ladder.

Key differences

The differences between the Ladder and these three building standards are fairly fundamental: BREEAM, LEED and Level(s) are all specifically designed for assets: buildings and the built environment, while the Ladder is an organisation-level management system, focusing on organisations and projects. While this may include buildings’ design, construction and performance, it is not limited to this. The Ladder therefore approaches carbon reduction from the organisation logic of direct, indirect and supply chain emissions (Scopes 1, 2 and 3) while BREEAM, LEED and Level(s) focus more on lifecycle stages related to products used in construction. Further, although the Ladder emerged from the infrastructure sector it is intended as a sector-neutral tool, which is therefore also used by organisations outside the construction sector.

On the other hand, the Ladder focuses on energy and CO₂ management, while BREEAM, LEED and Level(s) all address a wider range of sustainability issues, covering resource use, water, adaptation, public health and waste.

BREEAM, LEED and the Ladder are all based on external audits, but one difference is how the quality of those audits is controlled. The Ladder is an accredited system, unlike BREEAM and LEED, meaning these audit controls are carried out by independent accreditation bodies, currently the Dutch and Belgian Accreditation councils (RvA and BELAC).

Regarding procurement, the Ladder is designed for use in procurement, and offers a way for procuring authorities to reward contractors for their carbon reduction efforts, through a multi-level award advantage in tenders, incentivising suppliers to work structurally on carbon reduction. BREEAM, LEED and Level(s) are more suited to be used as technical specifications for the procurement of buildings, setting a minimum performance level for the eventual asset delivered.

Summary at a glance

Criteria	BREEAM	LEED	Level(s)	CO2 Performance Ladder
Scope	Environmental performance of buildings, built environment and infrastructure, dependent on the standard applied.	Monitoring the design and environmental performance of buildings.	Environmental performance of buildings, built environment and infrastructure, dependent on the standard applied.	Carbon and energy reduction management system for organisations and projects.
Structure	Multi-level certification of buildings.	Guidance and legal requirement (EU) for new buildings.	Multi-level certification of buildings.	Multi-level certification of organisations and projects.
Procurement	Could be used as a technical specification for the procurement of buildings.	Could be used as a technical specification for the procurement of buildings, until it is a legal requirement	Could be used as a technical specification for the procurement of buildings	Designed for use in procurement: offers multi-level incentivisation through award advantages in tenders
Validation	Third-party assessment, reviewed by BRE Global Ltd.	Not applicable	Third-party assessment conducted by GBCI	Third-party assessment conducted by accredited certifying bodies
Costs	Certification fees calculated per metre squared, could range from €2,000 to €50,000+. In addition the resources allocated to achieve a higher rating.	Guidance is freely available online. The resources allocated to implementing measures and the system will have a (capacity) cost.	Fees depend on project size, complexity and the rating system used, but could vary from $2,500-$20,000. USGBC members receive a discount. In addition the resources allocated to achieve a higher rating.	Costs of Ladder certification include: * Resources allocated to implement the management system and measures  * Certification process (audit) * Contribution to running the system (not for profit), based on turnover

Final Thoughts

BREEAM, LEED and Level(s) are focused sustainability standards for buildings, helping assess performance across a range of themes. While they can be used in procurement processes, that’s not their main purpose.

The CO₂ Performance Ladder, by contrast, targets carbon reduction at the organisational level and is specifically designed to be used in procurement, encouraging suppliers to reduce emissions structurally.

Together, the Ladder and building standards offer complementary approaches — one focusing on the organisation and supply chain, the others on the built environment itself.

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