Avoided embodied emissions
The emissions that would have occurred if a new material had to be manufactured and procured. This aligns with Scope 3, Category 1 under the GHG Protocol and ISO 14064-1 indirect emissions accounting.
Sustainability
Embodied carbon reporting in construction
Mutu helps construction teams measure embodied carbon through material reuse, giving clear visibility over emissions avoided and supporting more accurate sustainability reporting.
Construction emissions tracking
How Mutu calculates emissions from material reuse.
Construction and demolition activities account for a significant share of global energy-related carbon emissions. Embodied carbon reporting measures the emissions associated with producing and transporting materials, while construction emissions tracking software helps organisations reduce waste and improve sustainability outcomes across projects.
When surplus materials are reused through Mutu, teams can report the climate impact of avoiding new procurement and avoiding landfill disposal. Mutu keeps those figures separate, transparent and easy to understand.
- Embodied emissions avoided
- Landfill emissions avoided
- Region-specific default factors
- User-controlled overrides
- Transparent reporting for tenders
What Mutu reports
Two emissions benefits, reported separately.
When materials are repurposed through Mutu, two separate emissions benefits can occur. They are based on different baseline scenarios and should not be added together.
Avoided landfill emissions
The emissions that would have occurred if the material had been disposed of. This supports Scope 3, Category 5 waste reporting and national waste-to-landfill methodologies.
No double counting
Mutu does not combine embodied emissions avoided and landfill emissions avoided into one total. Each metric is shown separately to avoid misleading claims.
Transparent defaults
Mutu uses conservative default factors as starting values only. Users can override them on individual listings or through their Material Library.
Calculation approach
Simple, conservative defaults teams can override.
To keep Mutu easy to use, default emission factors are derived from leading carbon-emission sources in each country. Units in Mutu are user-defined and typically include a corresponding weight; emission factors are applied using this weight where available.
For embodied carbon emissions avoided, Mutu applies region-appropriate generic factors for five material classes selected by users in the platform.
Default data sources
- New Zealand: BRANZ NECO2 national embodied carbon platform
- Australia: NABERS National material emission factors database
- A1-A3 manufacturing emissions for embodied carbon
- One country-level construction and demolition landfill factor
Embodied carbon defaults
Default material factors by region.
These values are defaults for Mutu's five general material classes and can be overridden by users where more specific material data is available.
New Zealand defaults
| Material class | Value | Unit |
|---|---|---|
| Plastic | 0.65 | kg CO2-e / unit |
| Wood | 0.23 | kg CO2-e / unit |
| Metal | 3.95 | kg CO2-e / unit |
| Concrete | 0.15 | kg CO2-e / unit |
| Other | 2.94 | kg CO2-e / unit |
Aligned with BRANZ NECO2, with the Other category using the NABERS value where NZ data is unavailable.
Australia defaults
| Material class | Value | Unit |
|---|---|---|
| Plastic | 0.44 | kg CO2-e / unit |
| Wood | 0.37 | kg CO2-e / unit |
| Metal | 3.48 | kg CO2-e / unit |
| Concrete | 0.15 | kg CO2-e / unit |
| Other | 2.94 | kg CO2-e / unit |
Aligned with the NABERS National material emission factors database using conservative material-class defaults.
Landfill emissions
Carbon emissions redirected from landfill.
For simplicity and consistency, Mutu applies one default landfill emissions factor for construction and demolition waste per country. This represents avoided landfill emissions when materials are reused rather than disposed of.
0.16kg CO2-e per kg of material in New Zealand
0.13kg CO2-e per kg of material in Australia
User control
Override default factors when better data exists.
All Mutu emission factors are optional defaults. For any individual material listing, users can override emission factors directly on the listing or set organisation-specific values in their Mutu Material Library.
When a user supplies their own factor, Mutu uses that value instead of the default. If known values are available from an Environmental Product Declaration or other verified source, Mutu recommends using them to improve construction emissions tracking across projects.
Summary
Transparent carbon reporting for construction reuse.
Mutu reports reuse impact clearly so project teams can understand the financial and sustainability outcomes of the materials they already own.
- Reusing construction materials creates two distinct emissions benefits
- Mutu reports embodied and landfill emissions separately
- Embodied emissions avoided are the primary metric
- Landfill emissions avoided use a consistent C&D factor
- Factors differ by region and are fully transparent
- Users can override default values at any time
Appendix
Default factor source assumptions.
NZ source assumptions
| Class | Assumption | Source |
|---|---|---|
| Plastic | Membrane, PVC | NECO2 |
| Wood | Softwood | NECO2 |
| Metal | Steel reinforcement bar | NECO2 |
| Concrete | 50MPa, no reinforcement | NECO2 |
| Other | No NZ data, use NABERS value | NABERS |
AU source assumptions
| Class | Assumption | Source |
|---|---|---|
| Plastic | Plastic sheeting, minimum EF | NABERS |
| Wood | Softwood, average EF | NABERS |
| Metal | Bar and mesh reinforcing steel, max EF | NABERS |
| Concrete | 50MPa, average EF | NABERS |
| Other | Other/miscellaneous material, average EF | NABERS |
Next step
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FAQ
Embodied carbon reporting questions.
What is embodied carbon in construction?
Embodied carbon refers to the emissions generated during the manufacturing, transport and installation of construction materials. It is a key component of total project emissions and a major focus of sustainability reporting.
How does construction emissions tracking software work?
Construction emissions tracking software measures emissions by tracking material usage, applying emission factors and calculating carbon impact across projects. It provides visibility over emissions and supports sustainability reporting.
Why is material reuse important for reducing emissions?
Reusing materials avoids the need for new manufacturing and reduces landfill waste. This makes material reuse one of the most effective ways to reduce embodied carbon in construction.
Can users customise emission factors in Mutu?
Yes. Users can override default emission factors with project-specific values, allowing more accurate emissions tracking based on real material data.
Can Mutu be used as a construction carbon calculator?
Yes. Mutu uses material weight and a selected or user-supplied emissions factor to calculate embodied and landfill emissions avoided when materials are reused. Teams can use those figures as transparent evidence for reporting, tenders and project decisions.