www.hbo.com

The numbers

First visit

0.729 g CO₂e

Return visit

<0.001 g CO₂e

Hosting

unknown

LCP

408 ms

CLS

0.966

TTFB

6 ms

At 10,000 views a month this page emits about 65.6 kg CO₂e a year, roughly 269 km in an average petrol car. The estimate assumes 75% new and 25% returning visitors, a measured cache reload ratio of 0%, and world-average grid intensity. How we calculate this

1. Audit third-party servicessave ~0.149 g/visit (1.34 MB)High impact · moderate effort

   7 third-party domains account for 2.69 MB (55% 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.

   • d1mgq2hv32qvw2.cloudfront.net2.18 MB
   • 908946ad4aae.us-east-1.sdk.awswaf.com310 kB
   • cdn.cookielaw.org195 kB
   • wme-gep-graphql-prod.wme-digital.com2.1 kB
   • 908946ad4aae.7d431460.us-east-1.token.awswaf.com2.0 kB
   • geolocation.onetrust.com282 B

   WSG 3.5: Treat third parties the same as first parties
2. Lazy-load below-the-fold mediasave ~0.082 g/visit (734 kB)High impact · quick fix

   4 below-the-fold images/iframes (1.47 MB) 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.

   • euphoria-s3-2x3_0.jpg937 kB
   • house-of-the-dragon-s3-ka-logo-1080.jpg311 kB
   • curb-your-enthusiasm-9x16.jpg195 kB
   • hbomax-logo-iridescent-white.png23 kB

   WSG 2.9: Optimize media to reduce resource use
3. Reduce JavaScript payloadsave ~0.068 g/visit (616 kB)High impact · moderate effort

   25 scripts total 2.46 MB on the wire (8.42 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.

   • d776d2a6-9d22bdd0b1108e11.js1.05 MB
   • challenge.js310 kB
   • 55661-40dcbdc0661c2f0e.js266 kB
   • 279f243a-2331b9b9b58fe264.js167 kB
   • 90710-9a85dfc07ba50a89.js163 kB

   WSG 3.2: Minify and remove unused codeWSG 3.3: Modularize bandwidth-heavy components
4. Convert and compress imagessave ~0.067 g/visit (602 kB)High impact · quick fix

   3 images exceed 300 kB apiece.

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

   • euphoria-s3-2x3_0.jpg937 kB
   • quilt-march2025-darker.jpg406 kB
   • house-of-the-dragon-s3-ka-logo-1080.jpg311 kB

   WSG 2.9: Optimize media to reduce resource use
5. Serve images at the size they displaysave ~0.047 g/visit (427 kB)High impact · quick fix

   11 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.

   • euphoria-s3-2x3_0.jpg937 kB
   • house-of-the-dragon-s3-ka-logo-1080.jpg311 kB
   • curb-your-enthusiasm-9x16.jpg195 kB
   • lanterns-coming-soon-ka-1920.jpg94 kB
   • hard-knocks-training-camp-seattle-seahawks-ka…39 kB

   WSG 2.9: Optimize media to reduce resource use
6. 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
7. Upgrade compression beyond gzipsave ~0.043 g/visit (389 kB)Advisory · quick fix

   2.59 MB 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.

   • d776d2a6-9d22bdd0b1108e11.js1.05 MB
   • challenge.js310 kB
   • 55661-40dcbdc0661c2f0e.js266 kB
   • 279f243a-2331b9b9b58fe264.js167 kB
   • 90710-9a85dfc07ba50a89.js163 kB

   WSG 4.3: Reduce data transfer with compression
8. Set a page-weight budgetAdvisory · moderate effort

   At 4.92 MB per view this page rates F. 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
9. Remove the entry redirectAdvisory · quick fix

   The address that was scanned goes through 1 redirect before the document is served, ending at https://www.hbo.com/. 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://hbo.com/redirects to https://www.hbo.com/

   WSG 4.4: Setup necessary error pages and redirection links

Where the bytes are

• JavaScript2.46 MB · 25 req
• Images2.21 MB · 18 req
• Fonts114 kB · 3 req
• Data (fetch)54 kB · 8 req
• CSS51 kB · 3 req
• HTML18 kB · 1 req
• Data (XHR)3.4 kB · 2 req
• Other0 B · 1 req