An HVAC company booked 23 jobs in month one from after-hours calls
In plain words
Hall's uses a voice agent for after-hours calls. It takes the details, checks how urgent it is and books a service window.
What happened: 23 booked jobs in the first month.
Source: benian.ai ↗
How to do it yourself
Our suggested steps. The company didn't publish theirs.
- 1
Count how many calls you miss a week (check your phone log).
- 2
Write down your prices, service area and what counts as an emergency.
- 3
Set up the voice agent, connect Google Calendar or ServiceM8, and paste the prompt below.
- 4
Call it 20 times yourself pretending to be different customers.
- 5
Switch it on after hours first, then for overflow during the day.
The instructions to give the AI
Paste this into Retell AI (the free plan is fine), swap the [brackets] for your details, and test it on a few real examples.
This is one part of the setup. It won't connect to your phone, inbox or other apps on its own; the steps above cover that.
Agent instructions (prompt)
You answer the phone for [business], a heating and air-con company. Find out what the caller needs, where they are and how urgent it is. Quote only these standard prices: [list]. Book them into a free slot in the calendar and confirm by text. If it's an emergency ([define]), text [owner phone] right away. If you're not sure, take a message. Keep it short and friendly.
[Highlighted] = replace with your own details before you run it.
What you should get back: "Hall's Heating & Air — sorry your AC's out. I can get a tech there tomorrow at 8. Address?"
Written by Quickly and Good, inspired by this case.
More detail: tools, prices and what you'll need
The company used: Retell AI, Vapi or Synthflow voice agent
You could use: Retell AI, Vapi or Synthflow voice agent + Google Calendar or ServiceM8
- Retell AI
Phone voice agents that answer and make calls, book appointments and transfer.
Pay as you go, $0.07-$0.31/min; $10 free credit · Official site ↗
Prices from each tool's own pricing page, checked Oct 2026.
What you'll need
- ☐A phone number the agent can answer (from the voice platform or Twilio)
- ☐A voice-agent platform (e.g. Retell AI, Vapi or Synthflow)
- ☐Connection to your calendar or job system so it can actually book
- ☐A knowledge base: services, prices, hours, service area, FAQs
- ☐The agent instructions (prompt) and a call script
- ☐20+ test calls, including angry, confused and off-topic callers
- ☐Transfer to a human for emergencies and anything it is unsure about
- ☐Call-recording/AI disclosure that meets local rules
Can I do this myself?
Possible if you are comfortable wiring tools together and testing for a week or two. If not, hire a builder: most owners do.
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