Ask three vendors what an AI project for your HVAC, plumbing or roofing company will cost and you can get three answers that are an order of magnitude apart. That is not always a sign that someone is lying. The word "AI" covers everything from a $50 tool you configure yourself to a custom system wired into your dispatch software.
This guide does not hand you a price, because any single number would be wrong for most readers. It explains what moves the number, gives you public vendor rates you can verify and date, and lays out why a fixed-scope first project is usually the safest way to spend the money. For the bigger picture of where to spend it, start with AI for contractors: where to start.
The five cost drivers
1. Scope
The biggest driver by far. "Answer calls after hours" is one project. "Answer calls, text missed callers, follow up on estimates, reactivate old customers, score leads and report weekly" is another, several times larger. Most quotes that look far apart are quoting different scopes under the same label. Before comparing prices, write down what each one includes and what it leaves out.
2. Integrations
An AI tool that lives on its own island is cheap to set up and expensive to use, because your team copies information between systems. Connecting to ServiceTitan, Housecall Pro, Jobber or another field service platform takes real work: reading customers and jobs, writing new leads and notes back, handling duplicates, keeping statuses in sync. This is often where the largest share of effort sits. What each platform allows, and what you need to verify, is covered in our guide to AI integration with ServiceTitan, Housecall Pro and Jobber.
3. Voice minutes
Voice AI is billed by the minute, and the bill has several layers: the platform, the speech recognition, the language model, the synthetic voice and the phone line. Public examples below.
4. Messaging fees
Texting costs a fraction of a cent per segment, plus carrier fees, plus a one-time registration step for business texting in the US. Small per message, but it scales with follow-up volume. Registration and consent rules are covered in TCPA texting rules for contractors, which is general information and not legal advice.
5. Maintenance
AI systems are not install-and-forget. Phone numbers get ported, a field service integration breaks after a software update, a script needs a new service area, a seasonal promotion changes what the system should say. Someone has to own that, and the cost is either a monthly fee, your own staff time or an emergency call later. Ask about it before you sign.
Public rates you can check
The following are vendor-published rates we opened and read in October 2026. Prices change without notice, so check the linked page before you budget.
Phone line and voice minutes
- Twilio, US local phone numbers (pay as you go): $0.0085 per minute for inbound calls, $0.0140 per minute for outbound calls to the US and Canada, and $1.15 per month per local number. Twilio's page lists these as current as of August 2026.
- Vapi, a voice AI platform: its pay-as-you-go plan lists a platform fee of $0.05 per minute. Speech-to-text, language model and voice costs are passed through at the provider's rate, and phone line charges are billed by the telephony provider. Vapi's own calculator example for 1,000 minutes a month totals about $82 to $129. The page shows no effective date, so treat it as "as seen in October 2026."
To make that concrete, that range works out to roughly 8 to 13 cents per minute for the building blocks of a voice agent at 1,000 minutes. A shop with 600 answered calls a month averaging three minutes uses about 1,800 minutes. That is a calculation from the rates above, not a quote, and it excludes setup, integration and support.
Texting
- Twilio, US long-code SMS: $0.0083 per message segment, outbound or inbound, plus a carrier fee added per message. Listed carrier fees include $0.0035 for AT&T and $0.0045 outbound for T-Mobile. Twilio's page says "pricing current as of October 2026."
At those rates, 1,000 outbound segments to T-Mobile numbers cost about $12.80 ($0.0083 plus $0.0045 each). The registration process for business texting carries its own one-time and recurring charges, which vary by provider, so confirm them with whichever platform you use. See Twilio's SMS pricing page.
Answering services, for comparison
- Ruby, human virtual receptionists: its blog states human virtual receptionist service costs "$250 to $1,725" per month, depending on call volume, coverage hours and support needs. The page carries no publication date, only a 2026 copyright notice, and gives no figure for AI receptionists.
We could not open a primary source with a trustworthy price range for custom AI implementation work for small businesses. Articles that quote "$2,000 to $100,000" ranges are mostly consultant blogs and we have not cited them. If a source you trust quotes a range, ask for the scope behind it. A range with no scope is not information.
What the platform fees leave out
Look at the stack above and notice what it does not include: the work to design the call flow, write and test the prompts, connect the system to your software, register your texting, handle the edge cases and read the transcripts for the first few weeks. For a typical trades business, those labor items are the real project. The per-minute and per-message rates are the metered utilities underneath.
That is why two things that look identical on a vendor's pricing page, a self-serve voice agent and a scoped build, are not interchangeable. The first assumes you can do the design and integration work yourself. The second includes it.
Why a fixed-scope first project is sane
Open-ended AI engagements fail in a predictable way. The scope grows, the hourly meter runs, nobody can say what "done" means, and by month four you are paying for activity with no booked jobs to show.
A fixed-scope first project reverses that:
- A defined outcome. Booked jobs from named lead sources, not "AI transformation."
- A short clock. Thirty days to live, not a nine-month roadmap.
- A known cost. You can compare it to the revenue leak you sized and decide in an afternoon. Our guide to measuring AI ROI in a contracting business shows the payback math.
- A natural stopping point. At the end you have a baseline, a result and data to decide on the second project.
- Limited downside. If it does not work, you lose a small, known amount, not an open-ended retainer.
This is the shape of the Booked-Jobs Recovery System: fixed scope, live in 30 days, measured in booked jobs. Pricing is scoped on a call, because it depends on your phone setup, your field service software and which of the eight components you need. We do not publish a price on this page, and we would rather say so than hand you a number that does not fit your shop.
How to compare quotes
When you have two or three quotes, lay them side by side on these lines:
| Question | Why it matters |
|---|---|
| What is in scope, in writing? | Prevents apples-to-oranges comparisons |
| What does it integrate with, and who builds that? | Integration is often the largest effort |
| What is billed per minute or per message, and who pays the carrier fees? | Usage costs scale with success |
| What is the monthly cost after launch? | The ongoing number is the one that compounds |
| Who maintains it, and what is the response time when it breaks? | Systems drift |
| What is the success metric, and when is it measured? | Look for booked jobs |
| What happens if you leave? | Do you keep your numbers, scripts and data? |
If a quote cannot answer these in plain language, the price is not the problem. The quote is.
What to do next
Size your leak first. If you lose $8,000 a month to missed calls and slow follow-up, a project that costs a few thousand dollars to fix has a different risk profile than one that costs ten times more. Our post on what a missed call costs shows how to size the first one. Then, if you want help scoping, you can book a strategy call through AI strategy consulting and we will talk through your stack and what a first project should include.
Frequently asked questions
How much does AI cost for a small contracting business?
It depends on scope, integrations, voice and messaging volume and ongoing maintenance. Public metered rates are small, for example $0.05 per minute for one voice platform's hosting fee plus pass-through costs, but the largest cost is usually design and integration work. Get quotes in writing against the same scope.
Are AI receptionists cheaper than human answering services?
Not always, and it depends on what is included. Ruby lists human virtual receptionist plans at $250 to $1,725 per month. Self-serve AI tools can cost less per minute, but you or someone else does the setup and integration. Compare total cost for the same scope.
What recurring costs should I expect after launch?
Platform or subscription fees, voice minutes, texting fees, phone numbers and maintenance or support. Ask for each as a separate line.
Why choose a fixed-scope first project?
It gives you a known cost, a defined outcome and a stopping point, so you can judge the result in booked jobs before committing to more.