To determine if you need to have your carbon footprint verified and certified by an external entity, you must first analyze your sector’s requirements, applicable regulations, and client demands. External verification of the carbon footprint independently reviews the greenhouse gas (GHG) emissions inventory, while its certification and registration allow for the communication of results with greater credibility, transparency, and traceability. For products and services, the Environmental Footprint Institute’s EFI Program offers an international framework for verifying, certifying, registering, and publishing carbon footprints based on Life Cycle Assessment.

If your company is required to report under the Corporate Sustainability Reporting Directive (CSRD), register an Environmental Product Declaration (EPD), or bid for public administration contracts, external verification of the carbon footprint is usually mandatory. For exclusively internal use, auditing your figures is optional, although it is the most robust way to guarantee the reliability of the calculation and provide maximum credibility to the market.

Calculating and Verifying Are Not the Same

Carbon footprint calculation measures the amount of greenhouse gases emitted by a company or product. To obtain this data, actual consumption from the activity is collected and converted into GHG emissions using appropriate emission factors. The calculation methodology, inventory boundaries, and accounting and reporting criteria can be established according to recognized standards, such as the GHG Protocol, ISO 14064-1 for organizations, or ISO 14067 for products.

To perform this quantification, Solid Forest develops tools such as CCMetrics, our online calculator for organizations, or Air.e LCA, our professional Life Cycle Assessment (LCA) software.

Verifying the carbon footprint is a different process: an independent external verifying entity reviews the methodology, collected information, data traceability, calculations, and results, and issues the corresponding statement or certificate in accordance with the applicable scheme. The verifier does not necessarily repeat the entire study from scratch but evaluates the evidence and confirms that the result meets the established criteria.

Registering the footprint adds a third level: it incorporates the already verified assessment into an environmental communication program and allows for its publication and consultation. In the case of the Environmental Footprint Institute’s International Environmental Declarations and Environmental Footprints Program (EFI Program), environmental assessments based on the Life Cycle Assessment of products and services can be verified and registered, including carbon footprints, water footprints, environmental footprints, and Environmental Product Declarations.

These figures are not equivalent: a verified carbon footprint quantifies GHG emissions, while an EPD communicates a multi-criteria environmental profile according to applicable rules.

Concept	Carbon Footprint Calculation	Carbon Footprint Verification
Main Objective	Quantify the GHG emissions of an organization, product, or service.	Independently validate the accuracy and conformity of the figures.
Who Performs It?	The company’s internal team or a specialized environmental consultancy.	An independent external validation/verification or certification body.
Applicable Standards	ISO 14064-1, ISO 14067, GHG Protocol, and, where applicable, sectoral standards such as EN 15804 for construction products.	ISO 14064-3, ISO 14065, ISO 17029, according to the applicable verification scheme.
Final Deliverable	Carbon footprint report and emissions inventory (Scopes 1, 2, and 3).	External verification opinion, certificate, or statement.

When Verification Is Necessary

There are operational, regulatory, and commercial situations in which carbon footprint verification transitions from a voluntary decision to a requirement. In these scenarios, regulations, a tender, a client, or an environmental communication program may request documentary support issued by an independent third party before accepting the results.

For products and services, the EFI Program offers an international framework for verifying, certifying, and registering life cycle-based environmental assessments; when an organization decides to publish a footprint or an Environmental Product Declaration within this program, it must comply with its instructions and the applicable verification process.

Determining if it is mandatory to verify your carbon footprint depends directly on whether your entity falls into any of the following situations:

• Large companies and regulated reporting (CSRD): Organizations required to submit their non-financial information statement under European regulations must subject their sustainability information to an appropriate assurance engagement. This includes, where applicable, information related to GHG emissions reported in accordance with ESRS.
• Environmental Product Declarations (EPD): If you wish to communicate the multi-criteria environmental profile of a product through an EPD in programs such as The International EPD System, Global EPD, or the Environmental Footprint Institute’s EFI Program, the LCA study and the declaration must undergo the independent review provided by the program and the applicable Product Category Rules. An EPD should not be confused with a product carbon footprint: the former communicates various environmental indicators, while the latter focuses on greenhouse gas emissions.
• Public tenders and corporate purchasing: Increasingly, public administration calls for tenders and large private buyers require their suppliers to present official emission certificates supported by external carbon footprint verification.
• Registration in official registries with a seal: To access certain institutional registries and obtain official reduction or neutrality seals, environmental authorities request the technical report along with the verification report validated by the verifying entity.

When It Is Voluntary (and Why It May Still Be of Interest)

If your organization is not subject to any of the aforementioned regulatory or contractual requirements, carbon footprint verification is a strictly voluntary process. Many SMEs begin by measuring their data internally to detect inefficiencies and improvement opportunities, reduce energy and fuel consumption in their processes, and establish initial decarbonization targets without submitting the inventory for external review from the first year.

However, even if not legally mandated, independent verification can provide strategic and commercial advantages. For products and services, the EFI Program allows for the verification and registration of carbon footprints, water footprints, environmental footprints, and Environmental Product Declarations based on Life Cycle Assessment. Verified and registered assessments are published and can be consulted in the Environmental Footprint Institute’s public search engine, making it easier for clients and other stakeholders to check the communicated information.

1. Reduced risk of greenwashing: Review by an independent third party provides technical evidence to support sustainability reports, corporate reports, and commercial claims, without implying by itself that the product is completely sustainable, climate-neutral, or free of environmental impacts.
2. Competitive advantage in the value chain: Offering validated Scope 3 data facilitates environmental reporting for your corporate clients, making you a preferred supplier.
3. Access to sustainable financing: Banks and investors demand reliable environmental metrics when evaluating ESG criteria and granting sustainability-linked financing.

How to Certify and Register a Carbon Footprint with the Environmental Footprint Institute

The certification of a product or service carbon footprint at the Environmental Footprint Institute is processed through the EFI Program. This program facilitates objective assessment and transparent communication of life cycle-associated environmental impacts, and supports the public registration of carbon footprints, water footprints, environmental footprints, and Environmental Product Declarations.

1. Define the product, service, and scope: The functional unit, system boundaries, and applicable methodology are established.
2. Perform the Life Cycle Assessment: Data is collected, emissions are calculated, and the sources, assumptions, and criteria used are documented.
3. Prepare the technical dossier: The carbon footprint report and the documentation required by the EFI Program’s applicable instructions and rules are prepared.
4. Pass independent verification: A verifying entity reviews the methodology, data traceability, calculations, and conformity of the study.
5. Register and publish the footprint: Once approved, the assessment is incorporated into the Environmental Footprint Institute’s public registry and can be communicated with the corresponding distinctive mark, in accordance with its terms of use.

Advantages of Certifying Your Carbon Footprint with the EFI Program

Certifying and registering a product or service carbon footprint in an environmental communication program like the EFI Program allows for the transformation of a technical calculation into verifiable, traceable, and market-accessible information. Its main advantages include:

• Greater credibility and trust: The backing of an independent verifying entity reinforces the reliability of the communicated results.
• Reduced risk of greenwashing: Technical documentation and external review reduce the risk of making environmental claims without sufficient support.
• Transparent environmental communication: Information is presented with clear criteria, defined boundaries, and verifiable evidence.
• Competitive differentiation: A verified and registered footprint distinguishes the product or service from alternatives that only communicate internal calculations.
• Strengthening environmental image: Demonstrates a measurable commitment to evaluating and improving environmental performance.
• Stakeholder trust: Facilitates evaluation by clients, buyers, investors, and other interest groups.
• Support for responsible purchasing: Provides useful information in supplier homologation processes, supply chains, and tenders that request verified environmental data.
• Use of an environmental distinctive mark: Allows the use of the environmental quality seal or distinctive mark granted by the Environmental Footprint Institute, always in accordance with the EFI Program’s terms of use. This seal acts as a visible element of environmental communication and differentiation, but it is not an official seal from a Public Administration nor does it alone certify complete sustainability, climate neutrality, or the total absence of impacts.
• Public publication and verification: The registered footprint is incorporated into the Environmental Footprint Institute’s public search engine for easy consultation.
• Improved traceability, comparability, and transparency: Registration organizes environmental information and facilitates its interpretation and comparison within the applicable boundaries, rules, and methodologies.

What the Process Involves, Explained Without Technical Jargon

The external verification process consists of a systematic evaluation carried out by an independent verifying entity to confirm that the figures, methodology, and evidence do not contain significant errors, omissions, or inconsistencies.

For an organizational carbon footprint, the corporate inventory and its organizational and operational boundaries are reviewed; for a product or service carbon footprint, the life cycle scope, functional unit, data, allocations, and factors used are examined. When the objective is to register the assessment in the EFI Program, the review is also integrated into the documentary and publication procedure established by the program.

A carbon footprint verification usually consists of five main phases:

1. Risk analysis and planning: The verifier reviews the preliminary technical report to determine project complexity, identify critical calculation points, and establish the sampling plan.
2. Documentary review and inventory: The chosen scope (Scopes 1, 2, and 3) and the suitability of the applied methodologies according to international standards are checked.
3. Validation of primary evidence: Verification of electricity and gas bills, fuel delivery notes, waste management records, and logistical data is requested to confirm the traceability of activity data.
4. Verification of emission factors: It is analyzed that conversions to tons of CO2 equivalent use recognized and updated secondary sources, such as those published by the IPCC or official ministries.
5. Resolution of findings and opinion: The technical team addresses the observations from the verification. Once rectified, the certifying entity issues the final report and the formal verification statement.

What Documents the Verifier Will Request

During carbon footprint verification, the independent verifier will request the evidence that justifies each figure included in your emissions report. Having an organized documentary structure substantially shortens the external review period.

The required files vary depending on whether you are assessing an organization or a product, but they are usually divided into four main blocks:

• Primary activity data: Electricity consumption bills, natural gas consumption bills, fuel delivery notes, refrigerant gas recharge receipts, among other documents that allow for verification of the activity data used in the calculation.
• Logistical and supply chain information: Technical data sheets or records with raw material weights, transport delivery notes, distances traveled by suppliers, and records of business trips or employee mobility.
• Waste and water management: Certificates or receipts issued by authorized waste managers, collection and treatment delivery notes for hazardous and/or non-hazardous material, and meter readings or invoices or other records that verify water consumption.
• Methodological report and emission factors: Explanatory document of the inventory boundaries, justifications for selected emission factors (e.g., IPCC, MITECO, or other official databases), and spreadsheets with impact allocation that allow for justification and reproduction of the calculations performed.

Having cloud tools like CCMetrics or specialized software like Air.e LCA simplifies the export of these reports and allows for attaching the evidence required by the verifier without information gaps.

How We Prepare You for a Smooth Verification

To complete an external carbon footprint verification smoothly and efficiently, it is essential to prepare the technical dossiers with maximum precision before submitting them to the verifying entity. Submitting calculations with incomplete data or traceability gaps often leads to requests for clarification, extended timelines, and increased process costs.

When the purpose is to register a product or service footprint in the EFI Program, the preparation must also consider the program’s requirements, documentation for registration, and associated communication elements.

At Solid Forest, we bring over 15 years of experience assisting companies and industries in Life Cycle Assessment, carbon footprint, water footprint, and environmental footprint projects. Our team combines environmental consultants, chemical engineers, and IT professionals, allowing us to review the methodological robustness and IT quality of your databases before sending them to the certifying entity.

Whether you approach the project through our technical consulting services or manage your inventory tracking with our proprietary software, we also provide comprehensive support throughout the verification process. We help your team structure organizational boundaries, justify selected primary sources, and respond with technical rigor to any auditor requirements.

Do you want to certify and register the carbon footprint of a product or service with the Environmental Footprint Institute? At Solid Forest, we support you from calculation and Life Cycle Assessment to dossier preparation, independent verification, and registration with the EFI Program. Request advice to obtain a technically sound, traceable, and publicly communicable assessment.