In recent years, the construction sector has found itself at the center of the climate transition. Buildings account for approximately 36-40% of global energy-related CO₂ emissions, which is why European Union climate regulations are increasingly focusing on this area. Until recently, climate policies primarily concentrated on the operational emissions of buildings (operational carbon), meaning emissions generated during the use of a building – heating, cooling, ventilation, or electricity consumption.

However, with the development of climate standards and product life cycle analysis methods, a new approach has emerged: Whole Life Carbon (WLC). It refers to the analysis of greenhouse gas emissions generated by a building throughout its entire life cycle – from raw material extraction, through material production, construction, and operation, to demolition and disposal.

In practice, this means the need to apply the Life Cycle Assessment (LCA) methodology for buildings, in accordance with standards such as EN 15804, ISO 14040, or ISO 14044. Whole Life Carbon analysis is currently becoming one of the key tools used by:

• developers
• infrastructure investors
• banks financing projects
• investment funds
• climate regulators

What Whole Life Carbon is

Whole Life Carbon (WLC) is a concept describing the total greenhouse gas emissions generated by a building throughout its entire life cycle.

This definition includes two main components: operational carbon and embodied carbon.

Operational carbon refers to emissions generated during the use of a building, resulting from: heating, cooling, ventilation, electricity consumption, lighting systems, and the building’s technical infrastructure.

In the past, operational carbon was the main focus of climate policies in construction.

Embodied carbon refers to emissions associated with: raw material extraction, production of construction materials, transport, the construction process, maintenance, modernization, demolition, and waste processing.

In modern construction, embodied carbon can account for as much as 40–70% of the total emissions of a building across its entire life cycle.

Whole Life Carbon = Operational + Embodied Carbon

The total emissions of a building are therefore the sum of: Whole Life Carbon = Embodied Carbon + Operational Carbon

This approach enables a full analysis of the climate impact of a construction investment, which is crucial for new climate regulations and decarbonization strategies in the real estate sector.

Building life cycle phases (A1–C4)

The basis of the life cycle carbon building LCA methodology is the division of the building life cycle into standard phases defined in the EN 15978 and EN 15804 standards.

The life cycle is divided into the following modules:

1. Phase A – production and construction
   • A1 – raw material extraction includes: mining of metal ores, cement production, aggregate production, and timber harvesting. This is one of the most emission-intensive stages in the case of materials such as steel or cement.
   • A2 – transport of materials. Emissions resulting from transporting materials to production plants.
   • A3 – production of materials. Industrial processes: steel production, concrete production, glass production, insulation production. For many materials, A3 generates the largest carbon footprint.
   • A4 – transport to the construction site. Transport of materials from the factory to the construction site.
   • A5 – construction process. Emissions related to: operation of construction machinery, energy consumption on the construction site, construction waste
2. Phase B – building use
   • B1 – use. Daily use of the building without significant structural changes.
   • B2 – maintenance. Regular maintenance work.
   • B3 – repairs. Repairs of building infrastructure elements.
   • B4 – replacement of elements. For example replacement of: façade, windows, HVAC systems
   • B5 – modernization. Technological modernization of the building.
   • B6 – energy use. The most important component of operational carbon.
   • B7 – water use. Emissions associated with water production and distribution.
3. Phase C – end of building life
   • C1 – demolition. The process of dismantling the building.
   • C2 – transport of waste. Transport of materials to processing facilities.
   • C3 – waste processing. Recycling of materials.
   • C4 – disposal. Landfilling of waste.

The role of EN 15804 and ISO 14040 standards

The analysis of embodied carbon calculation building must be conducted in accordance with recognized international standards. The most important of these are:

1. ISO 14040 – a standard defining the general principles of Life Cycle Assessment. It specifies four basic stages of analysis:
   1. defining the goal and scope
   2. inventory analysis (LCI)
   3. environmental impact assessment (LCIA)
   4. interpretation of results
2. ISO 14044 – specifies methodological requirements for LCA in more detail.
3. EN 15804 – the most important standard for construction. It defines: the method of reporting emissions of construction materials, the structure of environmental data, and the calculation methodology for construction products. EN 15804 building carbon is the basis for documents such as Environmental Product Declarations (EPD).

How EPD is used

Environmental Product Declaration (EPD) is a verified document describing the environmental impact of a construction product across its entire life cycle.

EPD includes, among others: CO₂ emissions, energy consumption, water consumption, and global warming potential (GWP).

Data in EPD is provided for individual life cycle phases (A1–C4). Example:

A cement producer may publish an EPD containing emissions for: cement production (A1-A3), transport, and waste processing. In whole life carbon building calculation analysis, the data from EPD is multiplied by the number of materials used in the project.

Calculation example

If a building contains 1500 tons of concrete and the EPD of concrete indicates: 300 kg CO₂ per ton, then the embodied carbon for the concrete equals: 1500 × 300 kg CO₂ = 450 000 kg CO₂, that is: 450 tons CO₂

The biggest errors in LCA calculations

Despite the development of LCA building methodology, many analyses contain significant errors. The most common ones include:

1. Use of averaged data – instead of manufacturer data, average values from databases are used. This causes large deviations in results.
2. Omitting life cycle phases. Some analyses include only phase A1-A3. This leads to underestimation of emissions.
3. Lack of data updates – EPDs may be updated every few years. Old data may significantly differ from current production technologies.
4. Errors in units – a common mistake is mixing: kg CO₂, kg CO₂e, tons CO₂.
5. Incorrect interpretation of module D – module D describes potential benefits from material recycling. It cannot always be included in the emissions balance.

The problem of inconsistent data

One of the biggest challenges for embodied carbon buildings EU is the lack of consistency in environmental data. The problems include:

1. different LCA methodologies
2. different system boundaries
3. different assumptions regarding the building life cycle
4. varying quality of manufacturer data

In practice, this means that two LCA reports for the same building may differ by even several dozen percent.

Why methodology validation is necessary

With the development of climate regulations, the importance of the credibility of emission data is increasing. The reasons are simple.

1. Investment financing

Banks are increasingly making financing dependent on the level of building emissions, compliance with the EU taxonomy, and compliance with EPBD

2. ESG reporting

Investment funds must report emissions from their real estate portfolios.

3. Climate regulations

New EU regulations introduce emission limits for buildings and obligations to report life-cycle emissions.

4. Risk of greenwashing

Without methodology validation there is a risk of manipulating emission data.

The concept of Whole Life Carbon in construction is changing the way the climate impact of buildings is analyzed. Modern analysis of building emissions must include all life cycle phases (A1-C4), environmental data of materials (EPD), the Life Cycle Assessment methodology, and standards such as EN 15804 and ISO 14040.

At the same time, the real estate sector faces a serious challenge – ensuring consistency and credibility of emission data. Without validation systems and climate data infrastructure, it will be difficult to achieve the decarbonization goals of the construction sector and the implementation of the European Union’s climate policy.

In practice, this means that Whole Life Carbon will become in the coming years one of the most important parameters for evaluating construction projects – alongside investment costs and building energy efficiency.