Recurring Technical Causes
Unoptimized images, heavy page builders, stacked JavaScript, third-party widgets: why these sites are so heavy.
A label for the building, an oversight for digital
One finding runs through the entire study: hospitality environmental certification frameworks do not — or barely — include digital performance. Clef Verte evaluates water, energy, waste management, responsible purchasing, and guest awareness. EU Ecolabel measures building water and energy consumption, waste sorting, and materials used. Green Globe audits sustainable governance and physical environmental impact.
None of these labels evaluate the carbon footprint of the property's website.
Yet the website is the first point of contact with the guest. For 80% of travelers, the booking decision begins with an online search. The website is, literally, the front door of the hospitality experience.
The fact that La Clef Verte's own website — France's leading sustainable tourism label — scores only a D or E on EcoIndex illustrates the depth of this industry blind spot.
Clef Verte
Premier label tourisme durable en France
Green Globe
Certification internationale tourisme durable
Écolabel Européen
Extension aux hébergements touristiques
Manifeste R&C
Relais & Châteaux présenté à l'UNESCO
Core Web Vitals
Google intègre la performance web au SEO
3 000 Clefs Vertes
Record historique — 0 critères numériques
Why scores are so low: recurring technical causes
The technical analysis of the 50 audited sites reveals systemic causes, recurring from one property to another, regardless of size, standing, or certification held.
Unoptimized images: the number one factor
This is the most impactful and simplest lever to address. The majority of sites serve images at original size, without compression, without modern formats (WebP or AVIF), and without lazy loading. On some sites, images represent over 90% of total page weight.
A luxury hotel needs stunning images. That's non-negotiable. But modern formats allow dividing weight by 5 to 10 with no visible quality loss. A photographer delivers an 8 MB JPEG image. The same image in WebP with intelligent compression weighs 400 KB and remains visually identical on screen. Multiply by 30 images on a homepage, and the difference is colossal.
Heavy page builders
The Divi theme (WordPress), widely used in hospitality, generates thousands of lines of unused CSS and JavaScript. These "all-in-one" visual builders load all their features even if the site uses only a fraction. A typical Divi site loads more code than necessary simply because the theme includes features (sliders, galleries, animations) the site doesn't use — but which are still downloaded by every visitor.
JavaScript library stacking
Some sites simultaneously load Bootstrap, jQuery, Vue.js, jQuery Migrate, and other frameworks with redundant functions. It's like stacking five coats of paint: only the last is visible, but the weight of all layers slows everything down.
Uncontrolled third-party widgets
Facebook integrations, TripAdvisor, Google Maps, external booking systems — each widget adds dozens of HTTP requests and heavy scripts beyond the developer's control. A TripAdvisor widget alone can add 500 KB and 15 additional requests.
Full icon font loading
Font Awesome, loaded in its entirety on many sites, weighs several hundred kilobytes to display sometimes only 5 or 6 icons. Replacing it with inline SVGs for only the icons used would divide this weight by 20.
Moyenne 13x supérieure au seuil recommandé