Case Study — Prototyping a Personal Carbon Footprint Calculator for Concept Validation

Rafael Martins
8 min readJun 18, 2021

EcoNet is an early stage startup project with a strong focus on sustainability. The main goal of EcoNet is to create a digital solution that not only enables its users to measure their personal environmental impact but also, according to results, presents them with clear consumption alternatives and tips & tricks on how to improve in this aspect of their lives.

Timeline: 2 months (Freelance)| Role: UX Researcher | Project: EcoNet


The project of EcoNet was created by Joan Hereu with the goal of helping people who want to lower their environmental footprint to make better informed decisions everyday. After months developing a business model and value proposition, the project was in need of having its first prototypes in order to better communicate its intentions, and, most importantly, testing.

My role as the UX designer was to bring EcoNet to life through research, prototyping and testing. Thus, together with Joan, we defined the following challenge.

How Might We help people understand their environmental impact so that they can lower their footprint by taking more conscious lifestyle decisions?


The approach taken was of a a lean start-up method with a clear mindset of building, testing and iterating as fast as possible. This takes inspiration from the Design Thinking methodology. With that in mind, we took the following steps:

  • Exploratory co-working exercise with the goal of verbally define a basic, amplified and complete product together with targeted audience members.
  • Development of an online questionnaire to understand the profile, needs and wants of EcoNet’s users.
  • Benchmarking Analysis — Competitive and Strategic — to know how other market players build and market their products.
  • Building of prototype and validation round through user testing, based on the learnings from the previous exercise.
  • Further Usability Testing


Basic, Amplified and Complete Product

The goal of this co-work exercise was to define together with potential users the basic, amplified and complete product from their on point of view. First, we held 1:1 chats with 7 interviewees and, based on their answers, the exercise was translated into a online quiz in order to collect quantitative data. We followed up a top-down approach:

(1) Define the ideal product, with all amount of features and possibilities; by the end of this round, we’d have an elaborated and complex product with several funcionalities.

(2) Then, we asked participants to cut those features to 5 and then only to 3; not being aware of this exercise, they had to c the things that they find the most essencial.

(3) Finally, the last bit of this exercise is to choose only one characteristic that they find absolutely crucial to answer the challenge that we’ve defined in the BRIEFING section.

The results of this first exercise showed the following that the basic product of EcoNet should incorporate a personal carbon footprint calculator, which would not only help users to find products and solutions based on their profile but also allow to compare them to one another.

Results from the Basic, Amplified and Complete Product

Online questionnaire

I drafted an online survey with the goal of knowing more about EcoNet’s audience, their emotional profile, let’s say. Some of the questions that we were trying to answer are the following:

  • What are the motivations and pains in trying to pursue a more environment-friendly lifestyle
  • What is the available space in which EcoNet can occupy space in their lives
  • What are the main fields of action in which people struggle to be more sustainable in
  • And, most importantly, what is their biggest fear.


With the formulation of a basic, amplified and complete product, aligned with further research, we looked into competiton of EcoNet. We’ve looked into the main players that helped people calculate their carbon footprint, provided with information on sustainability features and did matchmaking with businesses.

An interesting fact that came to us is that this is indeed a very recent and new market opportunity. Most of the competitors of EcoNet are fairly new — mainly start-ups — dating back to foundations in 2018. This makes most of the competitors as emerging and are spread all around many countries all over the world. We’ve placed Capture, Onerz and PLAN3T as direct competitors due to their similar operations and geographical reach.

Benchmarking Analysis of EcoNet Competitors
Features Comparion of EcoNet’s main competitors


Persona Design

We imagined that Patricia would be a perfect fit to whom we’d design the carbon footprint calculator. We see her as The Pusher, someone who is trying to make a change in the world through her actions, pushing a more progressive and sustainable agenda.

Main Persona, Patricia

MoSCoW Diagram

After the research process being completely complete, we proceeded to define what were the main features that this first prototype would need to have. So, we defined different categories — UX Writing, Welcome Screens, Data Acquisition, Data Output, User Flow, Baseline Quiz and Information — and for each, we create list of Must Have, Nice to Have, Could Have and Won’t have.

Results of the MoSCoW Diagram Exercise

App Map


User Flow and Case Scenario

We created several Use Case Scenarios for Patricia and her interaction with EcoNet, of which we highlight the following to build our basic User Flow.

Use Case 1: Patricia wants to see which categories she is causing the most impact in

Patricia is curious about how much carbon she produces. She has access to the EcoNet app. Patricia goes through a basic questionnaire that gives an idea of how much CO2 she is producing already. Based on it, she can now see how much carbon she is expected to produce daily. Patricia can input data about different environmental categories any time

Use Case 2: Patricia wants to find recommendations on how to become more sustainable.

Patricia has access to her personal carbon emission tracker. She can see how she is doing based on different categories (diet, household, journey, recycling, etc.). EcoNet suggests different recommendations on how she can improve (either actionable or services she can use alternatively).

Basic User Flow for the prototype of EcoNet.


A low-mid fidelity prototype was built to test and validate the whole concept of EcoNet. Some specific points that we wanted to test are the following:

  • On-boarding: are users understanding the concept of EcoNet from the moment they sign in.
  • Baseline Quiz: how do users find the initial quiz to define their environmental profile — too long, too complicated, easy to understand?
  • Profile Page: do they find the information relevant and well categorised
  • Impact Calculation and Data Acquisition: how do users find data input for tailored recommendations
Initial Baseline Quiz Acceptance
Access to CO2 Calculation in different categories for personalised solutions
Results pages for specific category


We tested the prototype with 7 individuals, through 1:1 chats. Based on the conversations.

  • The initial proposed flow of the platform was too strick — in order to use it, one would forcibly need to go through a lot of steps. A outcome that came out was that not everyone was willing to spend time answering the initial quiz to create an environmental profile.
  • We also learned that the initial approach to collect data was too complex, it required a series of effort from the users and, consequently, should be rethought through at a technical level — could there be other ways to reach a good enough
  • Something that drives users is the “recommendations” and ways to improve their impact and that seemed to be what kept them motivated throughout the app;
  • A component of EcoNet was the social network, creating a community within the digital solution where users could exchange ideas and be inspired. Interestingly enough, it showed that wasn’t not needed nor valued.

The final Medium Fidelity Flow can be found in the following Link:

Some of the Final Screens


Based on the results that we’ve received, we’ve actually reached a point of business PIVOT. Basically, when a pivot happens, the course of the start-up changes — in this case, we’ve learned that the concept of a footprint calculator was not special or wanted.

What made us rethink the business pivoting were (a) the fact that users were skipping the initial quiz to define a physical profile and (b) the technical complexity that exists in order to define that profile. It was thanks to this real interaction and validation closer to the users that EcoNet was able to learn, grow and move on to something closer to what the market needs.

The learning was that the “carbon footprint calculation” is NOT crucial. The new formulated hypothesis is that users already know what they want and are looking for solutions, recommendations and businesses that help them feel good about their actions.


By working in a start-up project and having such an important role in it, made me learn a lot. Sometimes, pushing a test out and see how people act is what makes us propelled forward. It doesn’t need to be perfect, which for me as a designer was a hard pill to swallow. But it was good enough to extract so many learnings that, in the end, were instrumental in the pivot of the business of EcoNet.



Rafael Martins

Research & Design Consultant. UX. Service & Business Design.