OOH without greenwashing: building a credible campaign carbon footprint
One number can make a campaign look climate-friendly. It becomes meaningful when its scope is clear: screen electricity alone, or also manufacture, transport and maintenance? Is the result expressed per campaign week, thousand spots or thousand modelled contacts?
Methodology matters in outdoor advertising. Paper posters, illuminated city-light frames and digital screens have different life cycles and operating patterns. Fair comparisons need consistent boundaries.
Define the question before calculating
Establish the account's purpose: documenting a whole campaign, comparing similar buying options or identifying improvements. Define its reference unit too. Absolute campaign emissions answer a different question from emissions per week or per modelled contact.
A low per-contact figure does not automatically mean lower total emissions. A larger campaign may look more efficient per contact while emitting more overall. Conversely, a total alone says little about audience delivery. Report reach and carbon separately, and relate them only with transparent contact definitions and methods.
The GHG Protocol Product Life Cycle Standard recommends considering raw materials, manufacture, transport, use and disposal, with a clearly defined function or reference unit. For media campaigns, first establish the service being compared, then account for its emissions.
What belongs in a poster and site account?
Traditional outdoor accounting starts before a poster is put up. Relevant components include material manufacture and printing, recycled or virgin content, storage, transport, installation, replacement and disposal. The supporting structure has its own manufacture, installation, maintenance and, depending on format, illumination or mechanical operation.
The French Oneframe methodology published in 2026 includes poster and structure life cycles, manufacture, transport, installation, operation and end of life, covering 14 outdoor formats. It excludes creative content production from its OOH/DOOH framework. The document says the described AdOOHc calculator factors were last updated in June 2022. The framework is useful, but those factors should not automatically be treated as current German values.
For DOOH, electricity is only part of the account
Digital sites add actual electricity consumption, operating hours, brightness or operating mode, location and the emission factor used. Establish how the screen's operation is allocated to a particular campaign. One spot does not automatically account for all display energy.
Manufacturing matters too. A screen serves many contents over years; its embodied and end-of-life emissions need a reasoned allocation across usage or campaigns. Ad Net Zero's 2025 OOH/DOOH formulae cover physical production, materials, transport, installation and allocated digital-structure and end-of-life emissions. This is a transparent framework rather than a substitute for installation-specific data. Averages and assumptions must remain identifiable when measurements are unavailable.
Document the year and geography of electricity factors. Germany's Umweltbundesamt calculates annual electricity-mix values and reports an average of 363 grams of CO₂ per kilowatt-hour generated in 2024. This national annual average is not automatically the right factor for every site or procurement contract. State the factor, source and reporting year rather than treating “green electricity” as zero emissions without explanation.
Comparisons need common rules
OOH and DOOH can be compared when format, period, geographical coverage and communication task are compatible. Per-contact measures also need disclosed audience methods. A poster contact, modelled screen contact and observed gaze are different things. Oneframe notes that OOH/DOOH contacts are based on poster contacts or digital playouts; they should not silently be relabelled individual noticing or recall.
Cross-media comparisons require even greater care. An OOH campaign account, production footprint and digital-delivery figure may use different boundaries. A precise calculator alone does not make them comparable.
Show assumptions in the campaign report
A credible final report should disclose at least:
- System boundary: which phases and components are included or excluded?
- Data quality: which values come directly from operators or suppliers, and which are averages or estimates?
- Reference unit: the whole campaign, duration, surface, delivery or modelled contacts?
- Uncertainty and currency: the years of factors and activity data, and sensitivity to assumptions.
This follows GHG Protocol principles of relevance, completeness, consistency, transparency and accuracy. An estimate can be useful when identified as an estimate and updated once actual data becomes available.
Use the account to improve planning
An account is most helpful when it supports decisions. It can identify the importance of less material, longer use cycles, efficient lighting, consolidated logistics or appropriate campaign duration. What matters depends on the format and data; blanket rankings of “green” media oversimplify.
Ask for the calculation basis before booking: which boundaries are used, whether screens have actual consumption measurements, how structures and contacts are allocated, which factors and years apply, and whether reductions are reported separately from offsets.
This makes climate information a verifiable part of media planning. The useful figure is one whose origin, scope and meaning the client can understand.
Sources and context
- Ad Net Zero: OOH/DOOH/Transient Channel Emissions Framework and Formulae — Extended Version (2025). Industry methodology covering materials, transport, installation and allocated life-cycle emissions; not independent measurement of each campaign.
- Union des Marques: Oneframe V4 English (2026), OOH & DOOH section. French methodology overview; the documented AdOOHc factors date to June 2022 and are not automatically transferable to Germany.
- Umweltbundesamt: CO₂ emissions per kilowatt-hour of electricity in 2024. A national average, rather than a site- or contract-specific campaign factor.
- GHG Protocol Product Life Cycle Accounting and Reporting Standard. A general life-cycle standard, not designed specifically for outdoor advertising.
- AdGreen Carbon Calculator Methodology. Covers advertising production; used here to distinguish production scope rather than as an OOH media standard.
Editorial limit: this article explains accounting methods and does not certify providers or campaigns. Publish specific carbon values only with documented scope, data, factor year and allocation.