Why it matters on an HVAC site
The interactions that matter on a contractor site are few and high-stakes: tap to call, open the booking widget, submit the form. INP is measured on exactly those, not on scrolling.
It is also the vital most often ruined by things an agency added. Chat widgets, review carousels, call-tracking scripts and consent managers all run JavaScript on the main thread, and each one competes with the tap the visitor just made.
How to check it yourself
- Field data from the Chrome User Experience Report, at the 75th percentile.
- Search Console Core Web Vitals, which will attribute a poor INP to a URL group.
- In the browser, record a performance trace while tapping the call button and read the long tasks blocking the main thread.
Worked through in numbers
A site reports field INP of 540ms on mobile. Tapping the call button feels like nothing happened, so people tap it again.
A trace shows three long tasks firing on tap: a chat widget initialising, a review widget fetching, and a call-tracking script rewriting every phone number on the page.
Deferring the chat and review widgets until first scroll, and letting the call-tracking script swap numbers on load rather than on interaction, took INP to 180ms. Nothing was removed from the page.
Where this sits in the rankings
Scored under Technical SEO. How long the page takes to visibly respond when someone taps something.