Skip to main content
Running a Life Cycle Assessment used to be slow, technical, and difficult to explain across teams. Today, sustainability work is more collaborative — designers, engineers, procurement, and leadership all share responsibility for environmental performance.
This guide helps you run a full product footprint LCA in a single afternoon using a workflow built for clarity and repeatability. The focus is not just on producing results, but on building a structure you can reuse across products and teams. Sustainly supports this by combining transparent AI, centralized sustainability data, and guided steps that make LCA approachable for both beginners and experts.

​
What You Will Achieve

By the end of this walkthrough, you will have:
  • A clearly scoped LCA project with a well-defined functional unit
  • A structured inventory using reliable, traceable sustainability data
  • Impact results across core categories such as climate and resource use
  • Several improvement scenarios grounded in real design or sourcing decisions
  • A concise interpretation highlighting hotspots, uncertainties, and next steps
  • A shareable output aligned with your communication needs
A good first LCA isn’t about perfection — it’s about structure, transparency, and learning. Sustainly helps you build each of those pieces into your workflow.

​
Case Setup: Stainless Steel Bottle

For consistency, we’ll model a reusable 500 ml stainless steel bottle produced in the EU and transported by truck. The company is a small team with partial supplier data — a common starting point for SMEs and student projects. Functional unit: one 500 ml reusable bottle used for 3 years, hand-washed twice per week
System boundary: cradle-to-grave — materials, manufacturing, packaging, logistics, use phase, and end-of-life This example will help you see how assumptions shape the logic of your model.

​
Step 1. Define Goal, Scope & Assumptions

Clear goals save hours of unnecessary data collection and keep teams aligned. Goal: reduce product impact and generate decision-ready insights for internal communication.
Scope: cradle-to-grave; geography set to the relevant market; assessment intended for product teams and leadership.
Functional unit: fixed at project start and consistent across all scenarios. In Sustainly, the setup wizard helps you choose boundaries, regions, and modeling conventions so your project starts with a consistent structure.

​
Checklist

  • Clear goal linked to a decision
  • Functional unit written, saved, and stable
  • Boundary explained so stakeholders understand what’s included
Write your goal in a single sentence. If it takes two paragraphs, your scope is too wide.

​
Step 2. Build Your Life Cycle Inventory (LCI)

Start with what you know. A simple bill of materials and a few process assumptions are enough for a credible screening-level assessment. Example inventory:
  • Materials: stainless steel body, PP cap, silicone ring
  • Processes: forming, assembly, finishing
  • Packaging: cardboard box, paper leaflet
  • Transport: suppliers → DC → customers
  • Use phase: hand washing
  • End-of-life: recycling and disposal routes
In most beginner projects, the material stage dominates results — but capturing all stages helps reveal improvement opportunities. In Sustainly:
  • Upload a simple spreadsheet or add items manually
  • Use AI-assisted search to map materials and processes
  • Let the system harmonize units and resolve naming inconsistencies

Centralized Data

Keep all materials and assumptions in one shared place.

Audit-Ready Inputs

Track sources, dates, and proxies to increase trust.

​
Step 3. Choose Impact Categories

Before calculation, decide which indicators align with your goal. Climate is the most common, but it rarely tells the whole story. Many businesses also look at resource use, water-related indicators, or toxicity-related categories. In Sustainly, switching across category sets is instant. This helps teams explore results without rebuilding the model.
Always include at least one non-climate category. A narrow focus can hide unintended trade-offs.

​
Step 4. Model Scenarios

Scenario modeling turns your LCA into a design and sourcing tool. Focus on realistic levers:
  • Scenario A: baseline
  • Scenario B: higher recycled content
  • Scenario C: alternative transport mode
  • Scenario D: extended product lifetime
In Sustainly, clone the baseline, adjust one assumption at a time, and clearly label each scenario. Keeping changes isolated makes comparisons clearer and easier to explain.

​
Step 5. Run Impacts & Interpret the Results

After calculation, review the contribution of each stage. Look for patterns:
  • Hotspots: which materials or steps dominate?
  • Sensitivity: which scenarios meaningfully shift results?
  • Logic check: do flows and quantities make sense?
  • Trade-offs: where do improvements in one area worsen another?
Example interpretation:
The stainless steel body is the primary driver of climate impact due to its energy-intensive production. Increasing recycled content significantly reduces footprint, while changes in transport distance have a smaller effect. Extending product lifetime improves annualized performance across all categories. Uncertainty examples:
  • Generic data used for forming processes
  • Use-phase water temperature approximated
  • Average recycling rates applied
In Sustainly, you can annotate results directly — keeping insights, assumptions, and interpretations linked to the model.

​
Step 6. Export Deliverables

Choose outputs based on your audience:
  • Clear graphics for presentations
  • Data tables for internal tools
  • Structured reports for procurement or sustainability teams
Sustainly produces clean, shareable summaries anchored in the functional unit and system boundary you defined earlier.
All exports include your modeling assumptions and boundary definitions so results stay interpretable across teams.

​
Common Pitfalls & How to Avoid Them

  • Changing the functional unit mid-project → fix it early and keep it stable.
  • Using the wrong dataset for your region → always check geography before mapping.
  • Unit inconsistencies → stick to a simple, consistent unit system.
  • Over-focusing on climate only → include at least one more category.
  • Skipping scenarios → scenario analysis is where insights emerge.
Most credibility issues come from unclear boundaries or inconsistent assumptions — document them early.

​
Mini Walkthrough for Students (90 Minutes)

  1. Create a new project and run the guided setup
  2. Add materials and processes with basic inventory data
  3. Select at least two impact categories
  4. Clone your baseline into scenarios
  5. Export hotspot charts and write a short interpretation
This produces a complete, learning-ready LCA structure you can build on.

​
FAQ

How precise does my first model need to be?
Reasonable estimates are fine. Transparency matters more than perfect data, especially early on. Can I compare suppliers or design alternatives?
Yes — clone your baseline model and change only the supplier or material. Keep everything else identical. What if more data becomes available later?
Update inputs at any time. Sustainly rescales flows automatically and keeps previous versions documented.

​
Conclusion

A credible LCA doesn’t require complex software or specialist training — it requires structure, clear assumptions, and a repeatable workflow. Sustainly helps you stay organized, automate the tedious parts, and focus on the insights that drive sustainable business value. Start small, build consistently, and use each project as a foundation for the next.
From zero to insight is just the beginning.