Hiring Your First Engineer: Signs You’ve Outgrown Being a Sole Trader

Hiring your first employee is one of the biggest decisions you’ll make in your heating business. At some point, you’re not just a gas engineer any more. You’re a one-person business trying to do everything — and there aren’t enough hours in the day.

If that sounds familiar, you might be ready to take on your first engineer. But how do you know for sure? And what do you actually need to have in place before you bring someone on?

The signs you’ve outgrown being a sole trader

Most engineers don’t wake up one morning and decide to hire. It’s a slow build. The warning signs stack up over weeks and months until something forces the question. Here are the ones that matter.

1. You’re turning down work

This is the clearest signal. If you’re regularly saying no to good jobs because your diary is full for the next three weeks, you’re leaving money on the table. Every job you turn down is a customer who finds someone else. Some of them won’t come back.

2. Your admin is eating your evenings

Quoting, invoicing, chasing payments, booking jobs, ordering parts, replying to messages. When you’re on the tools all day, admin starts creeping into your free time. Is that a sacrifice you want to be making?

If your invoicing and scheduling are taking up your evenings and weekends, that’s a clear sign your workload has outgrown a single person.

3. Customers are waiting too long

This one’s dangerous because it erodes the thing that built your business in the first place: your reputation. When response times slip, quotes take days instead of hours, and service reminders aren’t going out on time, customers notice. They might not say anything — they’ll just quietly book someone else.

If you’re regularly apologising for slow responses or rescheduling jobs because you’ve overcommitted, your service quality is dropping. That’s a problem only more capacity can fix.

4. You can’t take a day off

When was the last time you took a proper week off without your phone buzzing? If the answer is “I can’t remember,” that’s not a badge of honour — it’s a business that depends entirely on you. One injury, one illness, and the whole thing stops. A second engineer doesn’t just grow your capacity. They give your business resilience.

Hiring your first employee — get your numbers straight

Gut feeling isn’t enough here. You need to know the numbers stack up before you commit to a monthly wage bill.

A useful starting point: look at how much recurring work you’ve got on your books each month — jobs booked, quotes accepted, services scheduled. If you’re consistently turning over enough to keep two engineers busy, you’re in the zone where hiring makes financial sense.

The true cost of an employee

The critical thing to understand is that a £35,000 salary doesn’t cost £35,000. Once you add employer’s National Insurance, pension contributions, a van, fuel, tools, Gas Safe registration, and insurance, the true cost is closer to £50,000–£55,000. That means your new engineer needs to be generating £75,000+ in billable work per year to make the hire genuinely worthwhile.

We’ve built an employee cost calculator that breaks this down properly — plug in your numbers and see what the real figure looks like. And our guide on how to calculate labour costs walks through the full breakdown if you want to dig deeper.

What you need in place before day one

Once you’ve decided to hire, there’s a checklist of things that need to happen before your new engineer starts.

1. Register as an employer with HMRC

You need to register for PAYE through the Government Gateway. Do this at least two weeks before your employee’s first payday — HMRC needs time to process it. Once registered, you’re responsible for deducting income tax and National Insurance from their wages and paying it to HMRC each month.

Tip: If payroll feels daunting, most accountants who work with heating businesses can handle it for £30–£60 a month. It’s worth it for the peace of mind.

2. Gas Safe registration

Every engineer doing gas work must be individually registered with Gas Safe. Your registration doesn’t cover them — they need their own. The annual fee is around £400, and they’ll need to have passed (and keep current) the relevant ACS assessments for the type of work they’ll be doing.

Check their Gas Safe card before they start, and verify it online.

3. Insurance and pension

Employer’s liability insurance becomes a legal requirement the moment you employ anyone. You need a minimum of £5 million cover, though most policies offer £10 million as standard. Expect to pay £300–£600 a year.

You’re also required to enrol your employee into a qualifying workplace pension within three months of their start date. The minimum employer contribution is 3% of qualifying earnings.

4. Contract and employment basics

Since April 2020, every employee must receive a written statement of employment terms on or before their first day. This covers their job title, pay, hours, holiday entitlement (5.6 weeks minimum), notice period, and where they’ll be working.

Don’t download a generic template from the internet and hope for the best. Get one that’s tailored to the trades — your accountant or a HR service can help.

Getting your systems ready for two people

Your new engineer needs to know where they’re going, what the job involves, what the customer’s been told, and what parts to bring. You need to know where they are, what they’ve finished, and whether the customer’s been invoiced. If you’re coordinating all of this over WhatsApp and scribbled notes, you’ll spend as much time managing them as you would have spent doing the jobs yourself.

This is where having the right job scheduling setup matters. A shared calendar where you can allocate jobs, see who’s where, and check progress without ringing each other five times a day. A system like GES keeps notes, photos, and customer history in one place — so when your engineer turns up at a property, they’ve got the full picture without needing to phone you first.

What to look for in your first hire

Your first employee sets the tone for everything that follows, so it’s worth being deliberate about who you bring on.

Experienced or newly qualified?

An experienced, Gas Safe registered engineer can hit the ground running. They’ll cost more, but they can work independently from day one. A newly qualified engineer is cheaper, but they’ll need supervision and mentoring — which means your time. Neither is wrong; it depends on whether you need immediate capacity or you’re happy to invest in someone longer term.

Reliability over brilliance.

For your first hire, you need someone you can trust to turn up, do good work, and represent your business properly. Technical skill matters, but attitude and reliability matter more. A brilliant engineer who’s unreliable will cost you customers.

Where to find them.

Word of mouth is still king in the trades. Ask around at merchants, mention it to other engineers, put the word out at your local Gas Safe training centre. College placement schemes are worth considering if you’re open to taking on someone newer. Online job boards work too, but you’ll spend more time sifting through applications.

The first 90 days — making it work

You’ve spent years building your reputation by doing every job yourself, exactly to your standard. Handing that over to someone else feels risky. What if they don’t do it the way you would? What if a customer complains?

They will do things differently. That’s fine. What matters is that the work is safe, competent, and professional. Set clear expectations from the start — how you want customer interactions handled, what your standards are for paperwork and sign-off, how quickly you expect jobs to be updated.