How to run a gas engineering business

The gas work is the easy part. Running the business around it, the pricing, paperwork, chasing renewals and getting paid, is where most sole traders lose time and money. This is the overview, with links to the detail.

What does your business need in place before day one?

• Qualify: an ACS route (CCN1 core plus your appliance categories), or an NVQ with a portfolio of real work.
• Register: you must be on the Gas Safe Register to work on gas legally, renewed every year.
• Insure: public liability cover at a minimum.
• Set yourself up to quote, invoice and keep records from day one.

None of these are one-offs. Registration renews annually, ACS reassessment comes round every five years, and the insurance certificate gets asked for by every letting agent you ever quote. Treat them as standing dates, not milestones you passed.

How do you price the work?

From your costed day rate, not from the going rate in a Facebook group. Add up what a working day actually costs, van, fuel, insurance, registration, ACS renewal, software, tools and the unpaid admin, then set the rate that covers it with margin. Quote fixed prices only for work you can see and scope; estimate, and say so, where there are genuine unknowns. The day rate and quoting guides walk through the arithmetic. The habit that matters is refusing to price below your own costs to win work you'd lose money doing.

How do you keep the cash flowing?

With habits, not heroics. Label every price as a quote or an estimate in writing, because a quote is a fixed price for defined work and an estimate is a best guess, and the customer will remember whichever suits them. Take a deposit when you're ordering materials you can't easily return, so a cancellation doesn't leave you owning someone else's boiler. Invoice the same day, ideally from the doorstep while the customer is still pleased with the work, with terms of due on receipt or 7 days for domestic customers; letting agents and commercial clients often run 14 or 30 days, so agree that before the work starts, not on the invoice. And if a business customer pays late, statutory interest on commercial debts runs at 8% plus the Bank of England base rate, which is a useful sentence to have ready for the follow-up letter.

How do you win and keep customers?

Repeat work is the whole game. A boiler installed is a service due every year after; a landlord won is a portfolio of annual CP12s; a letting agent won is many landlords at once. That's why the unglamorous things compound: turning up when you said, sending the record the same day, and reminding customers when the next service or renewal is due before they think of it. New-lead marketing has its place, and the getting-more-work guide covers it, but the cheapest job you'll ever win is the one from a customer you already have.

How do you stay legal as you grow?

Three cycles run underneath the business. Gas Safe registration renews every year. ACS qualifications are reassessed every five years, with a window before expiry to requalify without a gap; let them lapse and you can't legally work on gas until you reassess. And from April 2026, Making Tax Digital applies to sole traders with gross income over £50,000, meaning digital records and quarterly updates to HMRC, with the £30,000 band following in 2027 and £20,000 in 2028. None of these is difficult. All of them are dated, and dates are what slip when the diary is full of jobs.

What does the year's rhythm look like?

Lopsided, and plannable once you accept it. Winter fills the diary with breakdown work and no-heat emergencies; summer brings the lull. The engineers who ride it well use the quiet months deliberately: servicing rounds, landlord CP12 batches booked through the early-renewal window, and the jobs that need a wall opened up rather than a boiler nursed through a cold snap. Summer is also the time for your own dates. ACS reassessment is best booked in a naturally quiet stretch, late spring or summer for most domestic engineers, rather than in the winter you can least afford to spend off the tools. Treat your own renewals the way you treat a landlord's: dated, diarised, and started early enough that nothing lapses.

How do you keep the admin from eating your evenings?

By making the doorstep the office. The engineers who keep their evenings finish everything at the job: the CP12 done on the phone and sent before the van door shuts, the invoice raised from the quote, the card payment taken on the spot, the next renewal set to chase itself. Manifold is built around exactly that loop, records, renewals, quoting, invoicing and payment in one place, working offline in the plant room, and the digital records MTD expects fall out of it as a side effect.