Is programmatic digital out-of-home (pDOOH) really a lower-carbon way to advertise, and how would you know? The published per-impression figures for pDOOH are low compared with online display and video, but most of them come from companies that sell the media, so the safest approach is to understand how the numbers are built, estimate a screen's footprint yourself, and ask vendors the right questions before you repeat any claim.
This guide does all three. It looks at what the published figures say and where they stop, walks through a simple watts-times-hours estimate for a single screen, and ends with a list of questions to put to media owners and platforms.
What the published figures say
The most quoted comparison comes from VIOOH, a programmatic supply platform. In a November 2025 release published on ExchangeWire, VIOOH reported 0.041 grams of CO2e per pDOOH impression for 2024, against industry benchmarks of 0.84 g for programmatic display and 1.24 g for programmatic video. That works out to roughly 20 and 30 times lower. The calculation followed Ad Net Zero's Global Media Sustainability Framework and was carried out by VIOOH's sustainability partner.
Three caveats matter before you reuse those numbers:
- It is one company's data. The figure describes VIOOH's own supply, not every screen network.
- The benchmarks are not fully explained. The release does not say who produced the display and video figures or how.
- Methods are still changing. The release itself notes that the updated framework does not allow a like-for-like comparison with earlier years.
The direction of the result is plausible for a simple reason, explained below. The exact multiple is not something to put in your own marketing without checking the source and the method.
Why screens can score well per impression, and when they do not
A phone or laptop ad is delivered to one person at a time. A large screen in a busy station plays one ad to everyone passing at that moment, so its energy is shared across many impressions. That one-to-many delivery is the main reason per-impression figures for DOOH tend to be low.
The same logic tells you when the advantage shrinks:
- Quiet locations. A screen burning the same power for a handful of passers-by has a much higher footprint per impression.
- Running all night. Hours with almost no audience still use electricity unless the screen dims or switches off.
- New hardware. Manufacturing and installing screens has its own emissions, which an electricity-only estimate ignores.
- Heavy creative files. Large video files are copied to every screen in a campaign, and each copy uses network energy.
Hardware has improved. Daktronics, a display manufacturer, told Billboard Insider in August 2022 that a current 14 by 48 foot digital billboard uses about 23% of the power the first digital signs used in 2005. Efficiency gains like this lower the energy per play, but they do not change the basic arithmetic of audience size.
How to estimate one screen's footprint
You do not need specialist software for a first estimate. Energy is power multiplied by time, and emissions are energy multiplied by the carbon intensity of the electricity.
- Find the screen's average power in watts. Ask the media owner for measured consumption. If they give annual kWh instead, divide by 8,760 hours to get average kilowatts.
- Multiply by the hours it runs. Watts × hours ÷ 1,000 = kWh.
- Take your share. If your ad fills 15 seconds of a 120-second loop, your share of the screen's time is 15 ÷ 120 = 1/8.
- Apply a grid emission factor. kWh × kg CO2 per kWh = kg CO2. Use the factor for the country or grid region where the screen sits.
- Divide by plays or impressions if you want a per-unit figure to compare channels.
Illustrative example: one roadside billboard for four weeks
Illustrative example. The figures below are stated assumptions taken from the sources linked, applied to a hypothetical campaign. They are not measurements of any real screen. Buying a share of a rotating loop is also how these boards are priced, as our guide to how much digital billboard advertising costs explains.
- Annual energy: 26,000 kWh, the midpoint of the 24,000 to 28,000 kWh a year that Daktronics gives for a 14 by 48 foot digital billboard in the Billboard Insider article.
- Average power: 26,000 kWh ÷ 8,760 hours = about 2.97 kW, or 2,970 watts.
- Daily energy: 2.97 kW × 24 hours = about 71.2 kWh a day. (Annual figures already reflect real operating patterns, so this simply spreads them evenly.)
- Four weeks: 71.2 kWh × 28 days = about 1,995 kWh for the whole screen.
- Your share: a 15-second ad in a 120-second loop gets 1/8, so 1,995 ÷ 8 = about 249 kWh.
- Emissions: using the US average of 823.1 lb CO2 per MWh, or about 0.394 kg CO2 per kWh, from the EPA's greenhouse gas equivalencies references (eGRID 2022 data), 249 kWh × 0.394 = about 98 kg CO2.
- Per play: 30 plays an hour × 24 hours × 28 days = 20,160 plays. 249 kWh ÷ 20,160 = about 12.4 Wh per play, or about 4.9 g CO2 per play.
Using the low and high ends of the Daktronics range gives roughly 91 to 106 kg CO2 for the same campaign. To turn the per-play figure into a per-impression figure, divide by the number of people who see each play, which the media owner's audience data should provide. If that number were 50, for example, the result would be about 0.1 g CO2 per impression.
Two adjustments change the answer most. A screen on a cleaner grid, or on a verified renewable supply, has a lower emission factor. A screen that dims at night uses less energy than the even spread assumed here. Both are reasons to ask for real data rather than rely on averages. Our DOOH CPM calculator has a share-of-loop and plays tool that handles the same loop arithmetic.
What a simple estimate leaves out
The watts-times-hours method covers only the screen's electricity. A full footprint also includes the ad tech that selects and serves the ad, the transfer of creative files, and the manufacture and installation of hardware. Ad Net Zero's Global Media Sustainability Framework sets a common method for calculating media emissions across channels including out-of-home, and its resources are published as open access. In August 2025 the World Out of Home Organization announced it would help refine the framework for OOH formats, so the OOH method is still being developed. When a vendor quotes a per-impression figure, ask which version of the framework they used.
Removing printed posters does avoid printing, paste-up and the trips to change them. Digital screens trade that for continuous electricity use and hardware, so whether digital is better for a given site depends on how long it runs, how busy it is and how often the message would otherwise change.
Questions to ask media owners and platforms
- What is the measured annual electricity use of the screens on my plan, and is it metered or estimated?
- Do the screens dim automatically at night or in low light, and do any switch off during quiet hours?
- What electricity supply do they use, and can you show evidence for any renewable claim?
- Which calculation method do you use for campaign emissions, and which version?
- Does your figure include ad tech, creative delivery and hardware, or screen electricity only?
- Where does the audience figure behind your per-impression number come from?
- Can you report emissions for my specific campaign rather than a network average?
- What file size and format limits do you set for creative, and do you compress video?
- What happens to screens at the end of their life?
The answers also help with planning. Buying only the hours when your audience is present, a core advantage covered in our guide to programmatic OOH advantages, means your share of each screen's energy goes to plays that someone actually sees. The step-by-step guide to programmatic buying shows where those dayparting choices are set.
Before you call a campaign "green"
Environmental claims attract scrutiny from regulators. The UK Competition and Markets Authority's Green Claims Code sets out six principles, including that claims must be truthful and accurate, must not omit important information, must consider the full life cycle, and must be substantiated. Other countries have their own rules, but these principles are a sound test anywhere.
In practice that means:
- Say "lower estimated emissions per impression than our previous display campaign", with the method, rather than "carbon neutral" or "eco-friendly".
- Keep the vendor's calculation and the version of the framework on file.
- Do not borrow another company's multiple, such as "20 times lower", for your own campaign.
Sustainability data is becoming another campaign metric alongside reach and footfall. For how emissions reporting can sit next to your other results, see measuring pDOOH success, and for the basics of the channel, what pDOOH is.