The new Plausibility Checker allows Expert users to ensure high-quality building LCA assessments by providing more accurate, comprehensive, and customisable plausibility checks. The new version provides significant improvements by utilising AI that can handle more variables and scenarios. This makes it both more adaptable to specific project, regulatory, or certification scheme requirements and has the ability to improve over time based on feedback.
The checker uses data from real projects completed on One Click LCA, and multiple filters are applied to ensure their validity.
How your results are calculated
Our Carbon Heroes Benchmark tool automatically calculates results without being shown in the tool list on your project. This tool has a fixed scope for consistent calculation of projects that use different tools: embodied carbon (A1-C4), calculation period of 60 years, and only new construction. This means that results shown in the Plausibility Checker may look different from the results shown in your selected tool.
The new Plausibility Checker now supports a wider range of tools. For a small number of tools that do not calculate GWP in full alignment with the Carbon Heroes Benchmarks, the checker will instead use a limited set of mass-based benchmarks. This limited version applies to the following tools:
LCA according to Bygningsreglementet (2018 and 2025)
LCA for DGNB (all versions)
LCA for Qualitätssiegel Nachhaltiges Gebäude (QNG)
LCA for BREEAM UK IMPACT-compliant
The limited version of the new Plausibility Checker will also be made available for Business and Designer licenses. It will replace the legacy LCA Checker, which will be deprecated in January 2026.
Most tools are fully compatible with the standard benchmarks. However, the following tools are excluded due to significant differences in their calculation methodologies:
Energy Carbon
RE2020
How to use the Plausibility Checker
Once you have entered all building material data, the only mandatory parameter to generate plausibility calculations is Gross Internal Floor Area (IPMS/RICS).
Benchmarking is based on whole buildings, so the following elements should be included in your design scope. If any of these are missing from the design, you will still see checks based on these elements.
Foundations and substructure
Structure and enclosure
Finishes and other materials
Two scope elements are optional, and if they are not present the checks will be excluded.
External areas
Services
In addition to the design scope, the following optional project parameters are considered and will increase the relevancy and accuracy of the calculations for your specific project (in order of importance).
Building type
Frame type
Number of above-ground floors
Certification scheme
These details can be added when creating a project or by modifying a project after creation using the More actions button.
To access the new Plausibility Checker, go to the results page of a design and open the feature here.
The checker provides an overall project grade based on the number of checks that fall within the typical range for similar designs, and a detailed breakdown of each check performed in the table. The check icon is based on where the Project result falls within the Typical range:
Green check - the project result is between the 0.05 and 0.95 percentiles of benchmarked data. This is counted as 1 in the check grade.
Grey check - the project result and either the 0.05 or 0.95 percentiles both equal 0. This is counted as 1 in the check grade but the grey icon indicates that this is ‘inconclusive’, as other percentiles have values greater than 0.
Yellow check - the project is between the 0.0 and 0.1 percentiles or the 0.9 and 1.0 percentiles of benchmarked data. This is counted as 0.5 in the check grade, since it is at the limits of the typical range.
Red check - the project exceeds the 0.0 or the 1.0 percentile of benchmarked data. This is counted as 0 in the check grade.
By default, all checks are shown, but a dropdown is available to filter by Global Warming Potential (GWP) based checks, mass-based checks, and other checks (typically ratio-based). For each check, a tooltip provides an explanation of what data is used in the calculation.
The Benchmark values column visualises the results in a graph, and this can be expanded by hovering over it to expand into a larger detailed graph.
Validate checks
The checker now includes a new column with toggle buttons for users with Manager or Modifier rights on a project to manually validate whether a grey, yellow, or red check is acceptable within the context of the project.
An example might be buildings with a concrete or steel frame may typically use little or no cross-laminated timber (CLT) but your project does, resulting in a warning or failure. In this case, you can validate that this check is acceptable.
After validating checks, clicking the Save button at the top of the screen will recalculate the overall Grade. Grey, yellow, or red checks that have been validated are counted the same as a green check.