With SIBCA (Salon de l'Immobilier Bas Carbone) underway in Paris and the World Green Building Week just around the corner (September 8th - September), we're shifting focus to one of the most important conversations in construction:  carbon.

The Built Environment has a big role to play in the discussion on carbon. As per World Green Building Council, the construction industry globally contributes to 39% of the global energy related to carbon. 

By the middle of this century, the global population is projected to near 10 billion and with it, the total floor area of buildings worldwide is set to roughly double. A major concern is the emissions generated before a building even opens its doors, often called upfront carbon. These early-stage emissions are expected to account for about half of the total carbon footprint of new construction through 2050, putting significant pressure on the already limited global carbon budget.

‍

What Is MEP Embodied Carbon and Why It Matters

When we talk about a building’s carbon footprint, the focus often lands on energy use during operation. However, behind the walls, ceilings, and floors, mechanical, electrical, and plumbing (MEP) systems carry a massive hidden impact: embodied carbon.

As per UK GBC, embodied carbon is refers to the remaining 'emissions associated with materials and construction processes throughout the whole lifecycle of a building or infrastructure'. This is typically associated with any processes, materials or products used to construct, maintain, repair, refurbish and demolish a building. To details this out, refer to the chart below by RICS, embodied carbon is all the energy used to create a product during the construction process, i.e. the sourcing and manufacturing of raw materials. This is also often referred to as ‘cradle to gate’ or ‘cradle to site’. In the modular system of a whole life carbon assessment its known as A1-A3 – the product stage. It also covers A4-A5, the construction stage.

Embodied carbon also includes the carbon emitted throughout its ‘use stage’ (B1-B7) – the maintenance, repair or refurbishment required to keep it functioning. In addition to this, includes the energy released during a building’s ‘end of life’ stage (C1-C4). In whole life carbon assessments, it’s often referred to as cradle to grave. However, it can also include one final stage – the potential reuse, recovery, and recycling potential of the assets (D).

‍

‍

For MEP-specific activities the embodied carbon includes:

• Manufacturing of pipes, ducts, wiring, boilers, chillers, and more
  
  
• Transportation to the project site
  
  
• Installation and construction
  
  
• Maintenance, repair, and replacement during the building’s lifespan
  
  
• End-of-life disposal or recycling
  
  

According to GLA’s Whole Life Cycle carbon assessment guidance, the embodied carbon of building services in new buildings is on average 25% and in retrofits, it could be up to 75%.

‍

‍Why MEP Embodied Carbon Gets Overlooked

So why doesn’t MEP get the same spotlight as structure and façade? As per 2050 Materials, a platform and API that empowers professionals in the built environment to accurately evaluate environmental impacts at every stage, from design to procurement, there are a few reasons stand out:

• Data gaps: Product-specific EPDs (Environmental Product Declarations) for MEP gear are still hard to come by, especially for bread-and-butter elements like pipes, ducts, and controls. Without them, pinning down carbon impact feels like shooting in the dark.
  
  
• Low confidence in the numbers: To compensate, practitioners often add “uplifts” of 10-30%. That covers uncertainty, sure, but it also makes the results harder to compare across projects.
  
  
• Missed opportunities: Without reliable benchmarks, design teams can’t fully explore design choices, compare replacements, or stress-test against future regulations early in the process.
  
  

This underscores the need to prioritise MEP in carbon reduction strategies.

‍

Strategies to Reduce MEP Embodied Carbon

‍

Design Choices

• Compare materials (e.g., copper vs. PVC vs. steel pipes) based on GWP or Global Warming Potential which has been developed as a metric to compare (relative to another gas) the ability of each greenhouse gas to trap heat in the atmosphere. Carbon dioxide (CO2) was chosen as the reference gas to be consistent with the guidelines of the Intergovernmental Panel on Climate Change (IPCC)
  
  
• Reduce quantities by optimising layouts and system design. Prioritising passive design options that have impact on the MEP equipment. This means, for example, use of an openable window for ventilation that can reduce the need for mechanical ventilation systems.
  
  
• Right-size equipment and minimise refrigerant use. This becomes especially challenging since systems are often sized for worst-case scenarios and further capacity is added that causes oversizing and compromises the efficiency of the system.
  
  

‍

‍Quality Data

• Requesting EPDs from manufacturers helps push the industry toward better transparency.
  
  
• Use generic data only as a last resort.

‍

• Better methodologies push the envelope in the right direction: CIBSE TM65, already fairly popular, estimates product stage and end-of-life emissions (with uplifts for complex electronics), and the 2050 Materials Generic MEP Database, a curated, API-ready dataset covering major MEP components with functional design units and regularly updated factors.

‍

Policy & Collaboration

• Ensure MEP scope is included in green building standards (LEED, Living Building Challenge, etc.).
  
  
• Collaborate across teams to specify low-carbon products, recycle materials, and monitor refrigerant leakage.

‍

‍

Reducing the embodied carbon of construction materials represents one of the fastest and most impactful levers that the building sector has to cut emissions. Since the majority of embodied carbon is released at the very start of a building’s lifecycle its effect on the climate is immediate. Unlike operational carbon, which is spread over decades of a building’s use, embodied emissions are “front-loaded” and therefore critical to address now.

As mentioned earlier, circular and efficient design approaches ensure that materials are reused or minimised from the outset, lowering demand for virgin production. Advances in manufacturing processes, such as lower-carbon cement and steel, can significantly reduce the footprint of essential building components. In parallel, public policy and procurement standards that prioritise low-carbon products can create stronger market signals and accelerate adoption at scale.

Taken together, these approaches mean that the emissions reductions we achieve today will have a direct and measurable effect on hitting near-term climate goals for 2030, while also setting the foundation for deeper decarbonisation by 2050.

‍

References

• FloControl Ltd, Embodied Carbon Life Cycle in MEP Systems
• UK GBC
• Carbon Leadership Forum, Reducing Embodied Carbon in Building Systems
  
• One Click LCA, MEP 2040 Beginners Guide
  
  
• 2050 Materials, MEP Embodied Carbon: The Elephant in the Room

• World GBC

• RMI

‍