AI phone assistant for trades: three models, one recommendation

Three models to choose from, not twenty vendors

The vendor name settles very little. What matters is what happens once the caller hangs up, and in the trades that comes down to three designs: the AI answers and sends you a message, the AI answers and writes the job into your trade software, or the AI puts known numbers straight through to a mobile.

Company size decides alongside it. For 2025 the German skilled crafts association counts 1,038,126 businesses and roughly 6 million people working in them, which works out at 5.8 people per business, calculated here from those two figures. The typical buyer of these tools has no back office, just a phone in a jacket pocket.

The three models cost different amounts and solve different problems. The tariffs below are list prices as of 26 September 2026.

Model one reports, and does nothing else

A notification is not a callback. fonio says its assistant answers the call, transcribes the request and sends it by email, WhatsApp or SMS when nobody is reachable. HalloPetra says it delivers daily WhatsApp reports on which calls were taken and which appointments were booked.

The catch sits in the price list. At HalloPetra, WhatsApp is not part of the phone plan: by the vendor's own figures it costs 39 euros a month on top of the 99 euros for the solo tier. At 40 calls a month that is 138 euros, or 3.45 euros per call, counting the 250 minutes the tier includes.

This model suits firms that were going to return calls in the evening anyway. It moves the work to after hours rather than taking it away, and while you wait the caller collects three other quotes.

Model two writes into software you already run

The entry in the system is where the gain actually sits. HERO Voice says it qualifies the request with targeted questions, summarises every call, supplies a transcript and creates follow-up tasks such as a callback note or a quote, straight inside the system. Up to five conversations run in parallel.

Meisterwerk describes its newly flagged assistant Maxi more briefly: it answers calls and books appointments. Price, included minutes and per-minute rate are absent from the price page, which lists the base package with three users at 59 euros a month on annual billing. HalloPetra also pushes its data into the trade software you already use.

The precondition is strict. This model only pays off if the business genuinely uses that software every day. Run your jobs on paper slips and you gain a second filing cabinet, not a lighter workload.

Model three transfers the call, and that is often enough

Transferring beats transcribing whenever the boss can pick up. fonio says it routes callers to the right person and lists known numbers and the caller's own request among its criteria. HERO Voice offers a transfer to staff particularly for emergencies.

In practice that means regulars and site managers reach a mobile within two seconds, while unknown callers get qualified and logged. Talk time on the AI side falls sharply, and talk time is exactly what gets billed.

HERO names one limit itself: strong regional accents are not yet captured reliably. An assistant that cannot understand your regulars is an expensive hold queue.

Included minutes decide this, not the monthly fee

Across all four tariffs the monthly fee is the smaller item. The figures assume 2.5 minutes per call, set here as an assumption, and use the annual-billing list prices from HERO, fonio and HalloPetra. The rows were computed with python3: cost equals the monthly fee plus the minutes above the allowance times the per-minute rate.

• 40 calls, 100 minutes: HERO Select 71.00 euros (1.77 per call), fonio Solo 99.00 euros (2.48), HalloPetra solo tier 99.00 euros (2.48), HERO OS 109.00 euros (2.73)
• 120 calls, 300 minutes: fonio Solo 99.00 euros (0.82 per call), HalloPetra 114.00 euros (0.95), HERO Select 131.00 euros (1.09), HERO OS 139.00 euros (1.16)
• 300 calls, 750 minutes: fonio Solo 99.00 euros (0.33 per call), HERO OS 229.00 euros (0.76), HalloPetra 249.00 euros (0.83), HERO Select 266.00 euros (0.89)
• First tipping point: past 78 calls a month HERO Select costs more than fonio Solo, because 60 included minutes get topped up at 0.30 euros
• Second tipping point: past 100 calls a month HalloPetra's 250 included minutes run out, and every further minute costs 0.20 to 0.30 euros
• Human counter-check: those same 300 minutes cost 69.50 euros at the 13.90 euro minimum wage, which is 58 cents per call

What I would do in your place

For a two-person firm I would start with model three. Concretely: divert to the assistant after the fourth ring, put known numbers straight through, let everyone else be qualified, and send the summary to one address rather than three. That keeps talk time inside the allowance of the cheapest plan.

Yes, if the business has a fixed number, calls regularly get lost on site, and a job is worth three figures: at 852 euros a year for HERO Select with 40 calls a month, one saved job covers it. No, if the order book is full and new customers get turned away anyway, or if your customers speak in a strong regional accent.

Model two starts paying off at around five people, and only with trade software already in place. Model one I would never run on its own. How the same split by phone number plays out in other trades is covered in our pieces on car dealerships and repair shops.

Common questions

What is the cheapest way in? On annual billing HERO Select is listed at 59 euros a month with 60 Voice minutes, then 0.30 euros a minute. That covers 24 calls of 2.5 minutes, so one very quiet month.

Do I need a new phone system? No. All four vendors work through a divert to a number of their own; at fonio each extra number costs 7 euros a month by the vendor's figures.

Does this replace an office job? HalloPetra sets its 99 euros against a full-time office worker at roughly 3,500 euros. That compares answering a phone with a role that writes quotes and issues invoices. Per minute, a person at 58 cents undercuts all four tariffs.

The prices are vendor list prices as of 26 September 2026, and the 2.5 minutes per call is a set assumption, not a measurement.

The next step

Count calls for one week, not minutes. Your mobile's call log is enough: record answered and missed calls separately, and mark the numbers you recognise. The share of known numbers tells you directly how much model three saves you, because those conversations then use no assistant minutes at all.

Under 20 missed calls a month, leave it alone. Above that, listen to our AI phone demo to hear how one of these assistants sounds. Setup, the greeting and the transfer rules are covered by our AI phone assistant service, and our piece on AI cost per transaction shows how to run the numbers yourself.