Hire a receptionist or AI? A plumbing shop decision table
Hire for a seat, automate a gap. A decision table for plumbing, HVAC and electrical shops under 10 trucks, with the one-week count that decides it.
Hire a receptionist when the work fills a seat. Automate when the problem is a gap. Up to about four trucks, the phone, the board and the paperwork rarely add up to a full-time job, and many missed calls land when nobody would be at a desk. Automate first. From about five trucks, the board needs a person in office hours. Hire them, and let AI catch what one person on one line can't reach.
I'm a plumber, and I build AI phone receptionists for trade firms in the US and the UK. My first client, a plumbing company, goes live this month, so none of this is my own call data. It's government figures, vendor help pages and worked examples, all linked. I've done the wage maths in another post. This one is the decision. Two words first. A CSR is a customer service rep, the person who answers and books. In the UK you'd say office admin or call handler. And where I say trucks, read vans.
A receptionist is a seat. AI covers a gap.
That's the test. I call it seat or gap.
A seat is one person, on one line, in office hours. Inside those hours a good one beats any software I can build. Outside them the chair is empty. Housecall Pro says so on its own help page about when to hire: CSRs "typically work standard business hours and may miss calls during evenings or weekends".
A gap is every call no seat can reach. The one at 7 p.m. The one at lunch. The second call that comes in while the first is still going. The one that rings in your pocket while your arm is behind a cistern.
The same page gives the rule in one sentence. An answering service "might be a better solution for businesses that receive significant call volumes outside of typical business hours or wish to ensure 24/7 responsiveness without the overhead of additional full-time staff." They wrote it about answering services. It holds for AI too.
Most owners ask which one is cheaper. Ask which one you've got. Write "seat" and "gap" at the top of a page. You'll fill it in below.
Count the seat in minutes, not in trucks
Truck count is a rough guide. Minutes are the measure. For five working days, keep three tallies.
- Phone minutes in office hours. Calls in, calls out, and roughly how long each one took.
- Board and paperwork hours. Moving jobs, ordering parts, sending invoices, chasing them.
- Misses, with the time. Mark each one: outside office hours, or inside them while you or the office were busy.
The first two tell you whether there's a seat. The third tells you how big the gap is.
Worked example, four trucks. Say 20 calls come in a day at four minutes each. That's 80 minutes. Say 10 go out, for confirmations, parts and callbacks, at three minutes each. That's 30. Say the board and the invoices take 90. Total: 200 minutes, or 3 hours 20. Assume a full-time person gets six hours of real work out of an eight-hour day. You have a bit over half a seat.
Now eight trucks. Say 45 calls in at four minutes is 180. Say 25 out at three minutes is 75. Say the board and the paperwork take 150. Total: 405 minutes, or 6 hours 45. That's a seat, and it's over full. A full seat makes its own gap, because the person on a call can't pick up the next one.
A rough cross-check. In an EGIA snapshot survey of home service contractors from December 2020, 39% ran four to six technicians for every dispatcher. It's old, and the write-up doesn't give the sample size, so I wouldn't lean on it. It does fit the minutes. Somewhere around four to six techs, the board becomes somebody's job.
Run your own count before you read the table. Your numbers beat my examples.
The decision table for shops under 10 trucks
Find the row that sounds like your week.
| Your week | Seat or gap | Do this first | Then |
|---|---|---|---|
| 1 to 2 trucks. You answer from the job | Gap | Automate the phone. Don't hire | Count again when you add a truck |
| Most misses land after 5 or at weekends, at any size | Gap | Automate, or use a human answering service | Nothing. A day hire wouldn't be there either |
| 3 to 4 trucks. Three to six hours of phone and board a day | Half a seat | Automate the phone | Part-time office help when the paperwork hurts |
| 5 to 9 trucks. The board moves all day | Seat | Hire the CSR | Add AI for nights and the second line |
| One CSR already. Calls ring out while they're on a call | Gap on a full seat | Automate the overflow | Hire a second when callbacks and renewals get skipped |
| Most calls are complaints, warranty or members | Seat | A person, at any size | Software takes the message, nothing more |
Three notes on reading it.
The truck counts are where I'd expect the rows to fall. They aren't thresholds from a study. Your count decides.
"Automate" means one thing here. Catch the call, find out the job, the address and the urgency, and text it to a human. That's all mine does.
If your row says gap, the choice between a human answering service and AI is its own comparison. I ran it for HVAC, with the summer peak in it.
UK readers: if you're a sole trader, you're in row one or two. The phone rings a handful of times a day and you miss it up a ladder or under a floor. Nobody needs a desk for that. Prices in pounds are in the UK electricians post.
What the seat costs, and what you're buying
The BLS median for a customer service representative is $44,770 a year, as of May 2025. That category is economy-wide, retail included, so treat it as a starting figure. Someone who can run a trade board will often cost more. Wages are 70.0% of what a private employer spends per hour worked, so divide by 0.7. All in, about $64,000 a year. UK readers: the pounds version, with employer NI and pension, is in the office manager post.
Now put the phone next to that. Housecall Pro's help page runs its own example: seven missed calls a week, a $385 job and a 50% close rate come to "around $70,000 in annual revenue". Those are their numbers, not mine. Say four of your seven land after 5 p.m. A day hire catches the other three. Three a week, half of them closed, at $385, is about $30,000 a year. The $40,000 that rang at night is still ringing.
So in that example the seat doesn't pay for itself on phone money. That was never the reason to hire. You hire for the six hours of board and paperwork. And you hire for what Angie Snow, a CSR coach and vice president of an HVAC company in Utah, told a ServiceTitan webinar: "As CSR, you are the voice of the company." Her job, she said, is to build the relationship "so they trust us to come into their homes". Software doesn't do that.
The gap is cheap to cover. Jobber lists its AI Receptionist as a $29 a month add-on. Housecall Pro sells one named after the job: CSR AI "answers your customer calls, summarizes them" and notifies you after each one. If you already pay for either, try theirs before you look at mine. My builds start at $4,500, and the cost post says when that's worth it and when a cheap plan will do.
One more thing about the seat. The BLS expects customer service employment to fall 5% from 2025 to 2035 "as their tasks continue to be automated", and still projects about 289,500 openings a year. All of those openings, it says, come from replacing people who change jobs or leave work. I read that two ways. The simple calls are going to software everywhere. And the chair empties: holidays, flu, two weeks' notice. Whatever covers your gap also covers the day the seat is empty.
The first hire makes you an employer
This is the part nobody prices. A gap doesn't need a contract. A seat does.
In the UK, you must get employers' liability insurance "as soon as you become an employer", for at least £5 million, and you can be fined £2,500 for every day you're not properly insured. The same page says you don't need it if the only person you employ is a family member. If your partner does the books, check with your insurer which side of that line you're on. GOV.UK's employ someone guide has seven steps. They include a right to work check, a workplace pension check, a contract, and telling HMRC. If you're a sole trader whose phone rings eight times a day, that's a lot to pick up for a gap.
In the US, the SBA's hiring guide starts with an Employer Identification Number and goes on to state tax IDs, payroll and records. It lists workers' compensation under required benefits, and says unemployment insurance varies by state. I'm a plumber, not an employment lawyer. Check with your own advisor before your first hire.
None of that is a reason not to hire. It's a reason to hire for a seat and not for a gap.
What AI can't do in that seat
It can't run the board. It doesn't know the two o'clock is running long, which is why mine doesn't book appointments. It can't calm the customer who's been let down twice. It can't hear that a regular sounds off and ask what's wrong. It can't ring a lapsed member and talk them back. It catches, it qualifies, and it hands off.
Some callers want a person, full stop. What homeowners say about AI on the phone is in another post.
A person has limits too. One line. About 40 hours out of 168. Two calls at once means one rings out.
I recommend against buying AI more often than you'd expect. If your count shows you answer nearly every call, keep your money. If you miss two a week, ring back faster and you're done. Put your misses through the calculator before you spend anything.
Do this this week
- Keep the three tallies for five working days.
- Add up the minutes. Under three hours a day, there's no seat. Three to six is half a seat. Over six is a seat.
- Sort the misses: outside office hours, or inside them while somebody was busy.
- Find your row in the table.
- If it says gap, check what the software you already pay for can do. If it says seat, write the all-in cost down before you write the job ad.
If you'd like a second opinion on your count, book a growth call. Thirty minutes, free. If the answer is "hire a person and buy nothing from me", that's what I'll say. What I build for plumbing firms is on the plumbers page.
Questions people ask
Should a small plumbing company hire a receptionist or use AI?
Hire when the daytime phone, board and paperwork add up to a full-time job, which I'd expect from about five trucks. Use AI when the problem is calls nobody could reach anyway: after hours, at lunch, or while you're on a job. Count your phone minutes and your missed calls for one week before you decide.
How many trucks before I need a CSR?
There's no fixed number, so count minutes, not trucks. In my worked examples a four-truck shop has about 3 hours 20 of phone, board and paperwork a day, and an eight-truck shop has about 6 hours 45. In an EGIA snapshot survey from December 2020, 39% of home service contractors ran four to six technicians per dispatcher, which fits.
How much does a CSR cost a home service company?
The BLS median for a customer service representative was $44,770 a year in May 2025. Wages are 70% of what a private employer spends per hour worked, so the all-in cost is about $64,000 a year. Someone who can also run a dispatch board will often cost more than that.
Can an AI receptionist replace a CSR?
No. It covers the calls a CSR can't reach: nights, weekends, and the second line while they're on the first. It catches the call, finds out the job, the address and the urgency, and texts a human. It doesn't run the board, calm an upset customer or talk a member out of cancelling.
I'm a UK sole trader. Should I hire someone to answer the phone?
Probably not yet. A first employee makes you an employer. GOV.UK says you need employers' liability insurance of at least £5 million as soon as you become one, with fines of £2,500 a day if you're not properly insured, plus a pension check and telling HMRC. For a handful of calls a day, cover the gap first and hire when the work fills a desk.
Sources
- 1.Housecall Pro Help: Calculating your business capacity and when to hire (CSRs and techs) · Updated 21 January 2026; 'CSRs typically work standard business hours and may miss calls during evenings or weekends'; an answering service 'might be a better solution for businesses that receive significant call volumes outside of typical business hours'; example of seven missed calls a week, $385 a job, 50% close rate, 'around $70,000 in annual revenue'
- 2.BLS Occupational Outlook Handbook: customer service representatives · Last modified 27 August 2026; median pay $44,770 a year, $21.53 an hour, May 2025; employment projected to decline 5% from 2025 to 2035 'as their tasks continue to be automated'; about 289,500 openings a year, all from replacing workers who transfer or exit the labor force
- 3.BLS: Employer costs for employee compensation, June 2026 (released 9 September 2026) · Private industry: $46.89 per hour worked; wages and salaries $32.82 (70.0%), benefits $14.07 (30.0%)
- 4.EGIA Contractor University: Snapshot survey results, dispatching · Published 4 January 2021 on the December 2020 snapshot survey; '39% of home services companies employ four to six technicians for every one dispatcher'; sample size not given on the page
- 5.ServiceTitan: 4 essential steps to help your CSRs achieve a 95 percent booking rate · Published 29 June 2020; Angie Snow, CSR coach and vice president of Western Heating and Air Conditioning in Utah: 'As CSR, you are the voice of the company'; her job is to build the relationship 'so they trust us to come into their homes'
- 6.Jobber: pricing · Read 8 October 2026; Jobber AI Receptionist listed as an add-on at $29 a month
- 7.Housecall Pro Help: CSR AI overview · Updated 9 July 2026; 'CSR AI answers your customer calls, summarizes them, and notify you after each completed call'
- 8.GOV.UK: Employers' liability insurance · Must get it 'as soon as you become an employer', cover of at least £5 million, from an authorised insurer; fine of £2,500 for every day not properly insured; not needed if you only employ a family member
- 9.GOV.UK: Employ someone, step by step · Seven steps, including the right to work check, the workplace pension check, agreeing a contract and salary, and telling HMRC about the new employee
- 10.US Small Business Administration: Hire and manage employees · First step is an Employer Identification Number, then state or local tax IDs; workers' compensation listed under required employee benefits; unemployment insurance varies by state
Written by Ivar André Knutsen
I build and run AI systems, internal tools and workflow automation. You work directly with me from the first conversation through implementation and support. About Ivar
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