How ChatGPT and Google's AI pick which HVAC contractor to name

There is no list to get on

When a homeowner in Markham asks "who's a good furnace repair company near me?", the AI tool doesn't look up a directory of approved HVAC companies. It runs searches, reads a handful of pages and listings, and writes an answer from what it found. Nobody can buy a spot in that answer. Google says plainly that there's no way to request or pay for a better local ranking, and its AI features sit on top of the same systems.

That's good news for a small shop. The answer is built from public information, and most of that information is yours to fix.

Each tool reads a slightly different pile of information, though. Here's what each one says about itself.

ChatGPT: a web search, then a summary

When ChatGPT answers a local question, it usually searches the web and shows the sources it used. OpenAI's crawler documentation says its search crawler, OAI-SearchBot, is what surfaces websites in ChatGPT's search features, and that sites which block it "will not be shown in ChatGPT search answers". It's separate from GPTBot, the crawler used for training, so you can block one and allow the other.

What does ChatGPT end up reading? BrightLocal ran 800 local searches in ChatGPT in November 2024 and sorted the sources it showed. Business websites made up 58% of them, pages that mention businesses (news, guides, Wikipedia) 27%, and directories 15%. That's one study, in the US, almost two years old, and ChatGPT changes often. But the direction is clear: your own website is the single biggest input.

Google AI Overviews and AI Mode: Google's index, searched many times

Google's page on AI features says AI Overviews and AI Mode may use a "query fan-out" technique, "issuing multiple related searches across subtopics and data sources". A question like "furnace making a banging noise, who should I call in Vaughan" might trigger searches about the noise, about repair costs, and about local companies.

To be shown as a link in those answers, Google says a page must be indexed and eligible to appear in Search with a snippet. There are "no additional requirements" and no special markup or files needed. Google also says AI Overviews only show when its systems decide they add something, so many local searches still show the regular map and links instead.

In practice, if your website doesn't show up in ordinary Google results for a question, it's unlikely to be the page an AI Overview quotes. Our guide on why AI Overviews skip local contractors covers the usual reasons.

Gemini: Google Maps data

Gemini's help page on finding places says it uses public information from Google Maps to give "addresses, descriptions, websites, ratings, and opening hours for a place". Google's Maps grounding documentation for developers describes the same idea: the model retrieves places, reviews, photos and addresses from Maps before it answers.

For an HVAC company, that means your Google Business Profile is Gemini's main source about you. Wrong hours, a missing website link or a thin review history all flow straight into the answer.

What all three have in common

Put those together and three inputs do most of the work:

1. A website that can be read. Plain text that says what you do and where. Not blocked to Google's or OpenAI's crawlers. Not hidden in images or a PDF menu.
2. A complete, accurate Google Business Profile. Google says complete and accurate information helps you show up in local results, and that local results are based mainly on relevance, distance and how well known a business is, which Google calls prominence.
3. What others say about you. Reviews on Google and other sites, and mentions on pages you don't control. Google lists the number of reviews and links to your business among the things behind prominence.

Notice what isn't on the list: a secret AI file, a special kind of code, or a paid package. Google's own guide to generative AI search says it doesn't use llms.txt files or special markup, and that no third party has access to its ranking or AI systems.

Why answers change from one day to the next

If you ask ChatGPT the same question twice, you may see different companies. That's normal. The tools search again each time, and the person's location, the exact words and the day all change what they find. So one search proves very little, good or bad. Our guide on checking whether AI recommends you explains how to test properly, with a list of questions and a few runs of each.

Three checks for this week

You don't need a consultant for these. Each takes under half an hour.

1. Check that your site is open to the crawlers

Open yourdomain.ca/robots.txt in a browser. If you see Disallow: / under User-agent: *, Googlebot or OAI-SearchBot, ask your web person why. Also ask whether a security plugin or hosting firewall blocks "AI bots"; some do with one checkbox.

2. Read your Google Business Profile like a stranger

Search your business name on Google Maps on your phone. Check the category, hours, phone, website link and service area. Then check the last ten reviews. Would a homeowner in a hurry know what you fix, where you go and when you answer? Our Business Profile checklist walks through each field.

3. Ask the question your customers ask

Open ChatGPT, Gemini and Google. Type the question a real customer would ask, in their words, with your city: "furnace not turning on Brampton who can come today". Write down who gets named and which pages are linked. If a competitor keeps appearing, open the page that's cited and compare it with yours. It's usually more specific about services, area and hours.

What you can't control, and shouldn't pay for

You can't choose which question a homeowner types, where they're standing, or which model version answers. You can't pay for a spot in a regular answer. Anyone who says otherwise is selling something; see our guide on spotting AI snake oil from SEO agencies.

What you can control is the information these tools read. Keep it plain, keep it accurate and keep it the same everywhere. That's the whole game, and it's the same work that helps you in ordinary Google search.