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The updated ECI (MKI) weighting factors

Everything you need to know about the updated Environmental Cost Indicator (Dutch: Milieukostenindicator) and how to prepare for 2025

Artjom Janssen avatar
Written by Artjom Janssen
Updated over a week ago

The Environmental Cost Indicator (ECI) has evolved to align with the +A2 version of EN15804. As of 2025, government tenders will require the updated, +A2-aligned ECI scores. What are the characteristics of the new ECI scores, and how can businesses obtain them?

The Environmental Cost Indicator (ECI) combines all environmental impact categories of an LCA into a single monetary unit (€). This simplifies the comparison of products and projects and makes the ECI an important tool in the Dutch construction sector. For example, it helps determine the winning bid in public construction tenders.

The ECI methodology is described in the NMD assessment method, which is the Dutch elaboration of EN15804, the European LCA standard tailored for the construction industry. Despite the rest of Europe transitioning from the EN15804+A1 version to the EN15804+A2 version in July 2022, the ECI faced a delay. ECI weighting factors for the new +A2 impact categories needed to be established before fully transitioning to EN15804+A2. The weighting factors are now final, and the new ECI is complete.

This article will inform you:

● How the new ECI differs from the previous version

● How the new and ambitious ECI targets for buildings will be affected

● How and when companies should calculate the new ECI scores

What are (the new) ECI weighing factors?

“Weighting factors” translate impact category scores from a Life cycle assessment (LCA) into a single score. The ECI is such a single score and has the unit “euros”. The summation of these euro scores across impact categories and lifecycle stages provides the total ECI of a project. Other countries don't currently use such a single score - the ECI is as Dutch as windmills in tulip fields.

The new weighting factors for the +A2 impact categories were established based on the scientific research of CE Delft. In the autumn of 2023, they received approval from the Ministry of Infrastructure and Water Management and the Ministry of the Interior and Kingdom Relations.

The +A1 (Table 1) and +A2 (Table 2) versions of the EN15804 and their ECI weighting factors cannot be directly compared due to differences in impact category units and differences in the amount and types of impact categories. However, the effect of the ECI weighting factors for global warming and depletion of abiotic raw materials are comparable and are significantly higher than before.

According to Minister Hugo de Jonge, this reflects a CO2 price appropriate to meet Dutch national emission targets. The higher price for the depletion of abiotic raw materials will favor materials and projects that lead to less extraction of raw materials from nature - stimulating “reduce, reuse, recycle” and other circular economy principles.

Table 1: Old weighting factors

Table 2: New weighting factors. * “Climate change - total” is the sum of indicators “climate change - fossil”, “climate change- biogenic” and “climate change - land use and land use change”.

Difference between the old and new ECI score - an example calculation

To illustrate the difference between the old and new ECI, we calculated them for an EPS insulation board with a lamination layer. We applied a cradle-to-gate scope, which in the construction sector is divided into modules A1 (raw material supply), A2 (transport), and A3 (manufacturing)*.

*These module names are unrelated to the “+A1” and “+A2” versions of EN15804!

Figure 1: Contribution of modules to total cradle-to-gate (new and old) ECI.

When comparing the total cradle-to-gate ECI scores (sum of modules A1-A3) in Figure 1, the new ECI in this example has increased by 97.5%! However, the individual modules’ contribution to the total score is consistent between both versions. In this example, both under the old and the new ECI scores, raw materials (A1) cause about 89% of impacts, while transport (A2) accounts for a negligible fraction.

When looking at the contributions of impact categories to the total ECI in Figure 2, we see that the share of climate change impacts rose from 58 to 74 %. Newly added +A2 impact categories, such as particulate matter formation, contribute significantly to the ECI.

In any LCA, this type of contribution analysis is good to perform, to see which materials or processes contribute most to the environmental impacts. But it's especially relevant now that the ECI weighting factors have changed. For any questions about this, reach out to Sem Dijkshoorn.

Figure 2: Impact category scores and contributions to the total ECI, with old and new weighting factors.

Regulatory responses to the new ECI

The need to obtain an ECI score has put Dutch companies in a peculiar position: up until now, the NMD assessment method required them to assess according to both the +A1 and +A2 versions of EN15804 (to obtain the old ECI and to comply with European regulation, respectively). This need for double-reporting will fall away by July 1st, 2025, at the latest (see the section on NMD update below), and only the new ECI will be required in new government tenders.

Increased requirements for building sustainability

The government has set more ambitious targets for the sustainability performance of newly-built housing. The new maximum ECI score is 0.5 €/m2-floor-area for newly built housing and 0.85 €/m2-floor-area for newly built office buildings. However, this is based on the old ECI (+A1 version).

Closer to July 1st, 2025, these targets will be directly “translated” to the new ECI (+A2 version). These translated ECI targets will be higher numbers - but represent the same ambition level (see Figure 1).

Building regulations will include the target values based on the new ECI. While more detailed communication about the details and exceptions to this rule will follow, the construction sector should generally prepare for lower ECI targets.

NMD update in 2024

The NMD assessment method will be updated in 2024. This will certainly involve the adoption of the new ECI weighting factors and the abolishment of the need for double reporting. Additionally, the NMD database will be updated to “NMD3.9”, which will be based on Ecoinvent 3.9.1, and report +A2 and new ECI scores. Category 3 data (generic datasets), specifically, will be updated by the NMD foundation to +A2 scores so companies can recalculate their Environmental Product Declarations (EPDs).

At present, the exact timeline for these updates remains uncertain, hence pay attention to communication from the NMD for any developments. Ecochain and other LCA tools, such as Dubocalc, will update to the new ECI only after the NMD update.

What does that mean for companies?

Category 1 data in the NMD (based on EPDs from a specific supplier) and category 2 data (representative of EPDs from several suppliers in an industry branch) will not be automatically updated to +A2 scores! This means that owners of EPDs that are less than 5 years old, presently available on the NMD platform, and lacking +A2 information must supplement them with +A2 information by 2025*. This has been an ongoing effort supported by an “Acceleration Act” and an associated fund.

*Valid EPDs (less than 5 years old) will remain on the NMD even without +A2 data. However, they will not be useful for calculating projects’ ECI scores according to government regulations from 2025 onwards.

How to (re)calculate ECI scores

To prepare for obtaining the new ECI, you can already prepare your +A2 compliant LCI model in your preferred software tool using the NMD 3.5 or 3.8 database (we recommend Helix, the software for construction-related portfolio life cycle assessments. Alternatively, try Mobius to compare the ECI of different product designs). If you plan to verify your model, you can also start preparing the LCA background report. When the updated NMD guidelines and NMD 3.9 database are available, you only need to update certain items, but most of the work is already done! This ensures that in 2025 your new ECI scores will be in line with the latest guidelines.

Curious what your new ECI will look like? Use our ECI Excel calculator to measure it by yourself!

Can foreign companies calculate the new ECI based on EN15804+A2?

Foreign construction companies that want their products included in Dutch construction tenders must provide the ECI of their products. They do not need an EPD featured in the NMD, but their LCA needs to follow the NMD method. Otherwise, the calculated ECI is not valid.

Assessments according to EN15804+A2 do not necessarily comply with the NMD guidelines (although this is the case the other way around). For example, using the GaBi Database is allowed under EN15804+A2 but not in the NMD. Therefore, it won't be possible to simply calculate the new ECI from any existing +A2 scores.

Thus, to obtain the new ECI, non-Dutch companies can also prepare their model for the NMD update and then calculate their +A2 scores accordingly.


The new ECI weighting factors increase the overall ECI score, give more weight to global warming impacts, and aim to stimulate material circularity. From July 1st, 2025, only the new ECI scores will be useful in Dutch construction tenders. Companies with valid EPDs need to ensure they contain +A2 scores by 2025 - the Acceleration Act and an associated fund support these efforts. Companies that already have +A2 scores can soon obtain their new ECI scores from both Ecochain Mobius and Helix. Portfolio LCAs can already be prepared in Helix (sign up for a demo here), using the current NMD databases. When the updated NMD guidelines and NMD 3.9 database are available, you only need to update certain items to finalize your new ECI!


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