www.utn.de

The numbers

First visit

0.427 g CO₂e

Return visit

0.016 g CO₂e

Hosting

unknown

LCP

380 ms

CLS

0.003

TTFB

38 ms

At 10,000 views a month this page emits about 38.9 kg CO₂e a year, roughly 159 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 4%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.067 g/visit (592 kB)High impact · moderate effort

   8 third-party domains account for 1.18 MB (41% of the page).

   Remove services that no longer earn their place; load the rest on interaction (facades for embeds, delayed consent-gated tags). Each third party is also a privacy and performance dependency.

   • www.youtube-nocookie.com991 kB
   • siteimproveanalytics.com94 kB
   • fonts.gstatic.com41 kB
   • www.google.com25 kB
   • i.ytimg.com19 kB
   • 14 kB

   WSG 3.5: Treat third parties the same as first parties
2. Reduce JavaScript payloadsave ~0.038 g/visit (342 kB)High impact · moderate effort

   19 scripts total 1.37 MB on the wire (4.72 MB decoded). Bundles this size usually carry a lot of unused code.

   Split bundles per route, tree-shake dependencies, and audit with a bundle analyzer or coverage profile. A 25% cut is a conservative target for bundles this size.

   • base.js477 kB
   • front.js252 kB
   • m=r78Drb240 kB
   • m=root,base158 kB
   • siteanalyze_6341127.js94 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
3. Convert and compress imagessave ~0.037 g/visit (327 kB)High impact · quick fix

   8 images (726 kB) ship in legacy formats (JPEG/PNG/GIF).

   Serve AVIF (or WebP) with responsive srcset sizes, and re-compress oversized files. AVIF typically halves JPEG weight at the same visual quality.

   • AdobeStock_ontrastwerkstatt-201825436.jpg184 kB
   • 5-Jahre-UTN.jpg156 kB
   • Klimaschutz-AdobeStock_Studio-902873951-768x5…136 kB
   • UTN-AI-Robotics-s.jpg102 kB
   • AdobeStock-Tongpool_576305740-768x515.jpg94 kB

   WSG 2.9: Optimize media to reduce resource use
4. Optimize web fontssave ~0.025 g/visit (222 kB)Medium impact · quick fix

   8 font files total 502 kB, 4 not in WOFF2.

   Subset fonts to used glyphs, prefer one variable font over multiple weights, serve WOFF2 only, and consider system fonts for UI text.

   • fa-solid-900.woff2157 kB
   • fa-brands-400.woff2118 kB
   • PublicSans-Italic.ttf63 kB
   • PublicSans-Regular.ttf60 kB
   • KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBA.woff241 kB

   WSG 2.11: Use optimized web typography
5. Serve images at the size they displaysave ~0.011 g/visit (100 kB)Medium impact · quick fix

   3 images are encoded at more than twice the pixels the layout shows, even accounting for this viewport's pixel density.

   Generate multiple sizes and let the browser pick with srcset/sizes; a 4000px original behind a 400px slot spends bandwidth no screen displays.

   • AdobeStock_ontrastwerkstatt-201825436.jpg184 kB
   • 5-Jahre-UTN.jpg156 kB
   • UTN-AI-Robotics-s.jpg102 kB

   WSG 2.9: Optimize media to reduce resource use
6. Fix caching for returning visitorssave ~0.0019 g/visit (13 kB)Medium impact · quick fix

   On a repeat visit 52 kB of static assets were re-downloaded instead of coming from cache.

   Serve static assets with Cache-Control: public, max-age=31536000, immutable and versioned filenames so returning visitors download almost nothing.

   • fU31aDjwG5LnoCPMAjFC80TvW154TRquiYFtZDCu2ZM.jsCache-Control: public, max-age=31536000 · 25 kB
   • 6ceno Cache-Control header · 14 kB
   • www-widgetapi.jsCache-Control: public, max-age=31536000 · 9.1 kB
   • iframe_apiCache-Control: private, max-age=0 · 3.5 kB
   • image.aspxCache-Control: private, max-age=0 · 209 B

   WSG 4.2: Optimize caching and support offline access
7. Defer video and audioMedium impact · quick fix

   1 video autoplays.

   Never autoload media: use preload="none" with a poster image, load players on interaction, and stream in an efficient codec (AV1/HEVC).

   • UTN_Animation_02_16zu9_5.mp40 B
   • UTN_Animation_02_16zu9_5.mp40 B

   WSG 2.9: Optimize media to reduce resource use
8. Lazy-load below-the-fold mediasave ~0.019 g/visit (172 kB)Medium impact · quick fix

   3 below-the-fold images/iframes (343 kB) download immediately for every visitor.

   Add loading="lazy" to below-fold img and iframe elements (and keep it off the LCP image). Browsers then fetch them only when scrolling approaches.

   • AdobeStock_ontrastwerkstatt-201825436.jpg184 kB
   • UTN-AI-Robotics-s.jpg102 kB
   • fSODHiIEM2E58 kB

   WSG 2.9: Optimize media to reduce resource use
9. Verify your hosting energyMedium impact · moderate effort

   This host has not published renewable energy evidence with the Green Web Foundation, so its energy source is unknown.

   Choose a provider listed in the Green Web Directory, or ask your current provider to publish evidence (and a carbon.txt). This cuts the data-center share of every single page view.

   • carbon.txtNo carbon.txt found at the site root; publishing one is the lightest first step.

   WSG 4.1: Use sustainable hosting
10. Upgrade compression beyond gzipsave ~0.011 g/visit (94 kB)Advisory · quick fix

    627 kB of text ships gzip-compressed; Brotli or Zstandard would cut roughly another 15-20%, and browsers without them fall back to gzip automatically.

    Serve precompressed Brotli for static text assets (highest level, compressed at build time) and enable Brotli or zstd for dynamic responses; keep gzip only as the fallback.

    • front.js252 kB
    • siteanalyze_6341127.js94 kB
    • style.css60 kB
    • mediaelement-and-player.min.js39 kB
    • jquery.min.js31 kB

    WSG 4.3: Reduce data transfer with compression
11. Remove references to broken resourcessave ~<0.001 g/visit (896 B)Advisory · quick fix

    1 request answered 4xx/5xx on load: transfer and connections spent on nothing, on every single visit.

    Delete or fix the references (stale asset URLs, dead third-party tags). Each one is a request the page provably does not need.

    • trackHTTP 403 · 896 B

    WSG 4.4: Setup necessary error pages and redirection links
12. Set a page-weight budgetAdvisory · moderate effort

    At 2.88 MB per view this page rates E. The findings above list where the weight is.

    Agree a transfer budget (e.g. under 975 kB reaches a B), enforce it in CI, and re-scan after each change to hold the line.

    WSG 3.1: Set goals based on performance and energy impact
13. Remove the entry redirectAdvisory · quick fix

    The address that was scanned goes through 1 redirect before the document is served, ending at https://www.utn.de/. Every hop is a full round trip on a connection that has not warmed up yet.

    Point links, sitemaps and canonical tags at the final address, and make the host redirect in one hop rather than chaining http to https to www.

    • https://utn.de/redirects to https://www.utn.de/

    WSG 4.4: Setup necessary error pages and redirection links
14. Upgrade connections to HTTP/2 or HTTP/3Advisory · quick fix

    1 host serves five or more resources over HTTP/1.1, paying per-request connection and header overhead newer protocols eliminate.

    Enable HTTP/2 (or HTTP/3) on the server or move the assets behind a CDN that speaks it; multiplexing makes many small requests nearly free.

    • www.utn.de42 requests over http/1.1

    WSG 3.1: Set goals based on performance and energy impact

Where the bytes are

• JavaScript1.37 MB · 19 req
• Images734 kB · 18 req
• Fonts502 kB · 8 req
• CSS189 kB · 12 req
• HTML87 kB · 2 req
• Data (XHR)1.4 kB · 3 req
• Audio / video0 B · 2 req
• Other0 B · 1 req