sameAs
A markup property that says "this profile over here is also us". The cheapest identity work available and routinely skipped.
Checkable · the test is below
What it means
In your structured data, sameAs holds the URLs of your other official presences: your Google profile, your trade body page, your social accounts, your supplier listing. It is an explicit statement that these records describe one business.
Why it matters for an HVAC company
Contractors accumulate profiles over years and rarely connect them. Each one is a separate island of evidence about a business that may or may not be you. sameAs joins them up in a form a machine reads directly.
What would settle it
View your page source, find the structured data, and check whether sameAs exists and what it contains. Then open every URL in it and confirm each resolves to a live page that is actually yours.
A worked example
A contractor's markup lists four sameAs URLs. Two are dead, one points at a Facebook page last posted to in 2019, and one is correct. Replacing the dead entries with their active trade body listing and their manufacturer dealer page takes twenty minutes.