How the reivew works

A — Energy Efficiency, Cooling & Renewable Energy

Tourism's climate impact is larger than commonly assumed: research in Nature Climate Change found tourism's global carbon footprint reached about 8% of global greenhouse gas emissions, and UNWTO data attributes roughly 2 of those 5 percentage points specifically to accommodation. That's why cooling-system efficiency and shading carry the heaviest weight in our coastal/summer categories — cooling is the largest controllable energy driver for a property used mainly in hot months. Our inclusion of solar water heating reflects UNWTO's own identification of solar hot water, PV, and passive design as the mainstream low-carbon technologies already available to tourist accommodation.

B — Plastic-Free & Waste Management

This section reflects binding EU law, not just best practice: the EU Single-Use Plastics Directive, in force since July 2021 across all member states, bans single-use plastic cutlery, plates, straws, and polystyrene food containers. Industry estimates also suggest a single hotel room can generate up to 1 kg of waste per guest per night, much of it plastic.

C — Textiles, Bedding & Laundry

Laundry is one of the most water- and energy-intensive operations in short-term rentals, multiplied by every guest turnover. Field research on hotel linen-reuse programs found that guest-facing policy messaging measurably increases participation — which is why we score whether a laundry policy is actually communicated to guests, not just whether efficient equipment exists.

D — Location & Sustainable Mobility

Transport dominates tourism's carbon footprint. A study of Barcelona's tourism emissions found arrival and departure transport — mainly aviation — accounts for 95.6% of a trip's footprint. A host can't control how a guest flies in, but can control whether a rental car is needed once they arrive — the logic behind scoring walking distance to transit, beaches, and bike/EV access.

E — Guest Engagement & Education

Grounded in a widely cited hotel field experiment: signs telling guests that others already reuse their towels raised participation from 35.1% to 44.1%, more effectively than signs appealing only to environmental benefit, with more targeted messaging pushing participation as high as 50%. Infrastructure alone doesn't change guest behavior — visible communication does.

F — Water Conservation

The highest-weighted section in our coastal/summer categories, for good reason. The European Environment Agency reports over half of the Mediterranean region's population faces water stress in summer, with small Mediterranean islands under severe strain because they receive 10–15 times more tourists than residents. WWF data shows the average tourist uses roughly a third more water than a local resident, with summer water use in some areas running five times higher than in winter.

Our reef-safe sunscreen requirement in coastal categories reflects peer-reviewed findings that oxybenzone damages coral DNA and contributes to bleaching at extremely low concentrations — evidence strong enough that Hawaii became the first US jurisdiction to ban its sale, citing this research directly.