26. The Audited by IO8 label: what it says, what it does not say
Oct 08, 2026"If I display 'Audited by IO8', what exactly am I telling my guests? And if one of them disputes it, who answers?"
The short answer
The label says that IO8 measured and assessed your venue's environment on a given date, against a public grid of ten sub-objectives. It says nothing about the effect of a stay on a guest's health, and it is valid only for the date it carries.
The calculation or the proof
What is attested. An Audit (3,000 € excl. VAT) or a Longevity Mission (20,000 € excl. VAT) produces readings: CO2 at night, noise, evening and morning light, temperature, water. IO8's target values are indicative: CO2 below 800 ppm, noise below 30 dB, evening light below 2,700 K, 18 to 19 °C, filtered water, morning light above 1,000 lux. The 800 ppm value, for example, comes from a review carried out for ASHRAE (Akimoto et al., 2025). Each room publishes its own readings: the label points to figures, not to an adjective.
Why the date. A filter clogs, a ventilation system drifts. The Mission includes a re-measurement of the environment at six months. The label carries the date of the reading, and that date is what counts.
Why caution. Directive 2005/29/EC lists among the practices considered misleading in all circumstances displaying a certificate or quality mark without the necessary authorisation, or claiming that a product has been approved by a body when it has not (Annex I, points 2 and 4). Since 27 September 2026, Directive 2024/825 also prohibits sustainability labels that are based neither on a certification scheme nor on a public authority. The IO8 label is not a certification and claims no environmental performance: it is the mention of a private audit, named, dated, with a public grid.
What we cannot claim
The label attests no effect on a guest's health, sleep or ageing.
It is neither a certification, nor a public approval, nor a ranking between hotels.
It does not say that the venue has stayed within the same values since the reading. Only the date counts.
It does not say that the hotel buys from IO8. The report belongs to the hotel, IO8's interests are declared in it, and the hotel buys its equipment wherever it wishes.
What a hotel can do now
Always display the label with its date. Standard wording: "Room environment audited by IO8 on [date]. Readings available."
Link it to the figures. The label points to the room's readings, on the website or at reception.
Never associate it with a health word, neither "health room" nor "regenerating stay".
Know who answers. The hotel answers for what it publishes and for the upkeep of its rooms. IO8 answers for its measurements and its method, at the date of the reading.
Understand cross-referencing. The venue may say that it has been audited by IO8; IO8 only names an audited venue with its consent.
What the Living Lab measures
Measurement planned. The Living Lab, near Lisbon, is being equipped in waves. The same measurements will be taken in its own rooms and published here with their date: we apply to our own venue the grid we apply to others.
Sources
- Directive 2005/29/CE du Parlement européen et du Conseil du 11 mai 2005 relative aux pratiques commerciales déloyales des entreprises vis-à-vis des consommateurs, annexe I, points 2 et 4. eur-lex.europa.eu
- Directive (UE) 2024/825 du Parlement européen et du Conseil du 28 février 2024 (donner aux consommateurs les moyens d'agir en faveur de la transition verte), annexe I, point 2 bis, et article 4. eur-lex.europa.eu
- Akimoto M et al. New research on bedroom ventilation and sleep quality suggests that building standards should be revisited (ASHRAE 1837-RP). Science and Technology for the Built Environment, 2025. doi:10.1080/23744731.2025.2531317
The longevity audit for venues · The Research Journal
IO8 Living Lab, near Lisbon. Measured, never promised.
