+49 (0) 3382 7060 112   |   info@eaaca.org   |   Tool version V5_2026
AAC · NetZero · Carbon accounting

Wall LCA & Thermal Performance Calculator

Indicative calculation of U-value and GWP per m² wall area for transparent comparison of AAC wall assemblies and alternative constructions.

In accordance with Directive (EU) 2024/1275 (EPBD recast): this tool supports transparent communication of life-cycle greenhouse gas indicators for wall constructions. Results are indicative and depend on selected datasets and scenarios.
Important legal disclaimer and limitation of responsibility

Use of this tool is voluntary and at the user's own responsibility. The EAACA LCA Tool is provided by EAACA solely as a non-binding, indicative communication and comparison aid. It is not a verified environmental product declaration, not a verified building life-cycle assessment, not a declaration of performance, not a conformity assessment, not a certification, not engineering, design, legal or commercial advice, and not an approval of any product, construction, environmental claim or regulatory compliance statement.

By using the tool, the user acknowledges that the results are indicative only and that EAACA does not assume responsibility for the user's data, calculations, decisions, publications or third-party reliance on tool outputs.

Material database status

Internal material database ready.

This version stores all user data locally in this browser: the material database, saved wall constructions and the current comparison selection. No external materials.json file is loaded or required. Decimal inputs accept both comma and point, e.g. 12,5 or 12.5 mm.

Recommended for normal use: one file containing materials, saved constructions and comparison selection.
Advanced export / import options

Use only when needed: separate exports are useful if you want to exchange only the material database without replacing saved constructions. Saved constructions are normally secured via the complete backup.

Advanced / maintenance

Use this only if the local browser material database is damaged or if you intentionally want to replace your edited material database with the embedded starter version. Export a complete backup first if you want to keep your own changes.

1. Wall build-up

Layer Material Thickness [mm] Product share [%] Share mode Quantity [m/m² or kg/m² wall] λ [W/(mK)] R [m²K/W] Use for U-value Replacement cycles A1-A3 A4-A5 B1 B2 B3 B4 repl. C1 C2 C3/C4 D GWP basis Apply changes
Resulting B1 reduction factor Fa: 1.00. Select coating type and single-sided or double-sided coating. Fa is applied only to negative B1 values.
Tip: values in the table are edited first and recalculated after clicking Apply, Refresh / recalculate construction, or after moving/copying layers.
Important quantity note
For materials entered as kg CO₂e/lfdm linear product, enter the required running metres per square metre wall area in Quantity [m/m² or kg/m² wall]. For materials entered as kg CO₂e/kg material, enter the mass per square metre wall area, e.g. 20 kg/m² for reinforcing steel. Example for studs: vertical studs at 625 mm spacing ≈ 1 / 0.625 = 1.60 lfdm/m²; with top and bottom rails add 2 / wall height. If the construction has negative B1 values, select the B1 coating type and coating position for the complete construction.
Save / load wall build-up construction Save the current layer table as a reusable built-up construction, or load a saved construction back into the table.

Module values in the layer table are shown in kg CO₂e/m² wall area. Product share [%] describes the construction share of a component and can be used for mixed systems such as timber frame walls, e.g. timber studs 15% and insulation 85%. The new Share mode controls whether this share is applied to GWP or whether the entered quantity already represents the real consumption per m² wall. For mortar, reinforcement or linear profiles entered as real kg/m² or lfdm/m², use Quantity includes share to avoid double reduction. “Replacement cycles” defines additional replacements within the reference period: 0 = no replacement, 1 = one replacement, 2 = two replacements. For example, a layer with one replacement is counted twice in the life-cycle calculation: once as the initial layer and once as replacement in module B4. Note: product share affects GWP and, for adjacent partial-area layers with the same thickness whose shares sum to 100%, also the U-value calculation via an automatically calculated equivalent λ-value. Linear and mass-based products such as CW/UW profiles or reinforcing steel can be switched off for the U-value calculation using “Use for U-value = No”.

2. Results for current construction

U-value [W/m²K]–
GWP A-C incl. B modules [kg CO₂e/m²]–
Module D separately [kg CO₂e/m²]–

Layer share by module and total

Each bar shows how strongly the layers contribute to the module result and to the A-C total. The value at the right is the net module result in kg CO₂e/m² wall. For readability, segment widths are based on the absolute layer contributions within each row, so negative values such as recarbonation credits or module D credits remain visible.

Module kg CO₂e/m² wall

Layer-resolved module diagram

Report / PDF output

The report preview opens directly here and can be printed or saved as PDF via the browser print dialog.

3. Construction library and comparison

Comparison library

Comparison actions: Saved constructions are managed in the local construction library. Use the checkboxes to select up to 10 variants for the diagram. Use Clear comparison to uncheck selected constructions without deleting them. Use Delete selected comparisons to remove checked constructions from the local library.

Use the checkboxes to select comparison variants. “Clear” only removes them from the diagram; “Delete” removes them from the local construction library.
Construction Layers U-value [W/m²K] B1 surface A-C [kg CO₂e/m²] D [kg CO₂e/m²] Select for diagram Actions

Comparison diagram, max. 10 constructions

Up to 10 saved constructions can be selected for comparison. For presentation charts, 3 to 5 variants are usually easier to read. Saved constructions are stored locally in this browser and can be removed directly from the comparison library table.

4. Add or edit material

Material editor note
The material editor supports arithmetic in module fields, e.g. 10.75 + 1.48 or 8,5 + 2,25. The calculated numeric result is saved. The material editor supports both options: kg CO₂e/m³ material, kg CO₂e/m² wall area, kg CO₂e/lfdm linear product and kg CO₂e/kg material. If kg CO₂e/m³ is selected, the GWP result is multiplied by layer thickness in metres. If kg CO₂e/m² is selected, the GWP values are used directly. If kg CO₂e/lfdm is selected, the GWP values are converted using running metres per m² wall. If kg CO₂e/kg is selected, the GWP values are converted using kg material per m² wall, e.g. reinforcement mass. B4 is calculated from the replacement cycles of each layer.
Use this field to document where the material data comes from. It is saved with the material database and exported in backups.

Backup tip: use Export complete backup before replacing the HTML file or before using another browser/computer. Use Export material database only if you intentionally want to exchange materials separately.

5. Methodology and legal disclaimer

For standard materials with the input basis kg CO₂e/m³ material, module results are converted to kg CO₂e/m² wall area by multiplication with layer thickness in metres.

Product share [%] can be used for products that cover only part of the wall area, such as timber studs in a timber-frame wall or mortar in masonry. The new Share mode defines the GWP calculation: Apply share multiplies the environmental values by the product share. Quantity includes share keeps the share visible for documentation but does not multiply GWP again, because the entered quantity already represents the real consumption per m² wall. This is recommended for mortar, reinforcement, anchors and linear profiles when quantity is entered as kg/m² or lfdm/m². Replacement cycles are shown in module B4. In this prototype, B4 is calculated as the additional product, transport/construction and end-of-life impacts of the replaced layer: B4 = replacement cycles × (A1-A3 + A4-A5 + C1 + C2 + C3/C4). Module D is shown separately and is multiplied by the total number of layer occurrences. Product share affects GWP results. For adjacent partial-area layers with the same thickness whose shares sum to 100%, the U-value calculation uses an automatically calculated equivalent λ-value for the parallel layer.

C1 and C2 are shown separately. C3/C4 is combined because a layer is normally either routed to recovery/recycling or to disposal in a scenario, not both as independent alternatives.

U-value calculation uses: U = 1 / (surface resistance + Σ d/λ). For external walls, the default is Rsi + Rse = 0.13 + 0.04 = 0.17 m²K/W. For internal or adjacent-space situations, the selectable default is 0.13 + 0.13 = 0.26 m²K/W. Layers such as CW/UW profiles may be excluded from the simplified U-value calculation while remaining included in GWP. This tool does not replace a verified EPD according to EN 15804 or a project-specific building LCA according to EN 15978.

Legal note
Legal disclaimer: The tool is provided as a non-binding, indicative communication and comparison aid only. EAACA assumes no contractual, advisory, monitoring, verification, certification, design, update or other obligation towards the user or any third party. Users are solely responsible for all input data, assumptions, scenarios, interpretation and use of results. To the maximum extent permitted by applicable law, EAACA excludes liability for losses arising from use of or reliance on this tool. Mandatory liability that cannot be excluded by law remains unaffected.