Domestic vs Commercial Gas Engineers in the UK: What You Need to Know
Most engineers start out in the domestic field, working in homes and small properties. But commercial gas is a completely different pathway, with its own qualifications, responsibilities, and opportunities. Some engineers make the transition to commercial as a way to progress their career, take on bigger projects, and increase their earning potential.
In this article, we’ll cover the differences between domestic and commercial gas engineers.
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What is a commercial gas engineer?
A commercial gas engineer is trained and qualified to work on larger gas systems and appliances typically found in businesses, schools, hospitals, factories, and other non-domestic sites. These systems go beyond the scale of what you’d find in a normal home — they often include high-output boilers, plant rooms, complex pipework, or catering equipment in commercial kitchens.
Differences Between Domestic and Commercial Gas Engineers
| Aspect | Domestic Gas Engineer | Commercial Gas Engineer |
|---|---|---|
| Typical Customers | Homeowners, landlords, letting agents | Businesses, schools, hospitals, factories, housing associations |
| Typical Jobs | Boiler servicing/repairs, installations, landlord safety checks | Installing & maintaining high-output boilers, plant rooms, pipework, complex heating or catering systems |
| Work Environment | Homes and small properties | Large buildings, industrial sites, commercial premises |
| Training & Registration | Gas Safe Register – domestic categories (e.g. CCN1) | Gas Safe Register – requires additional categories (e.g. COCN1, TPCP1A, ICPN1) |
| Work Style | Lots of smaller, customer-facing jobs | Longer, more technical projects; often team-based |
| Earnings (approx.) | £28,000–£38,000 per year (self-employed engineers can earn more depending on workload) | £35,000–£50,000+ per year, with higher rates for specialist roles |
| Career Progression | Sole trader, small business, strong local reputation | Larger contracts, management roles, specialist technical fields |
Where Do Commercial Gas Engineers Work?
Commercial engineers are needed anywhere gas is used at scale. Typical workplaces include:
- Schools and universities – maintaining heating across large campuses.
- Hospitals and care homes – keeping critical systems safe and reliable.
- Factories and warehouses – managing complex pipework and heating systems.
- Offices, hotels, and retail spaces – building-wide heating and hot water systems.
- Apartment blocks – plant rooms supplying multiple dwellings.
- Commercial kitchens – servicing and installing gas appliances for catering.
Heating vs Catering Commercial Gas Engineers
It’s worth noting that commercial gas covers two main areas:
- Commercial heating engineers – focus on heating systems, boilers, and pipework in large buildings.
- Commercial catering engineers – work with gas appliances in restaurants, hotels, schools, and other kitchens.
Both require separate Gas Safe categories, so you must train specifically for the type of commercial work you want to do.
Additional Qualifications Needed for Commercial Gas
If you already hold domestic tickets, you’ll need extra modules to go commercial. Common ones include:
- COCN1 – Core Commercial Gas Safety
- ICPN1 – Installation of Commercial Pipework
- TPCP1A / TPCP1 – Testing & Purging of Pipework
- CODNCO1 – Changeover from Domestic to Commercial
- CCC1 – Core Commercial Catering Gas Safety (if moving into catering)
These are delivered by accredited training centres and build on your existing CCN1.
Thinking of moving from domestic to commercial?
Become a Gas Engineer Software user and get a 10% discount on any gas course from Logic4Training.
How Domestic Gas Engineers Can Become Commercially Registered
Here’s the general pathway if you want to make the jump:
- Hold domestic qualifications (CCN1 and appliances).
- Gain supervised commercial experience (many training centres recommend this).
- Take the CODNCO1 assessment, which bridges domestic to commercial.
- Add modules like ICPN1 or CCC1 depending on whether you’re going into heating or catering.
Becoming dual-qualified opens up new earning opportunities and makes you far more flexible in the jobs you can take on.
FAQs
How do I know if I am qualified to work on an appliance?
The Gas Safe Register has published a technical bulletin with a flow chart that helps you quickly and easily identify whether you are qualified to work on an appliance. It’s especially useful in slightly more unique circumstances.
You can find the bulletin here.
Can a domestic gas engineer work on commercial?
No — unless you hold the relevant Gas Safe commercial qualifications, you cannot legally work on commercial appliances or systems.
Can a domestic gas engineer service a domestic boiler in a commercial property?
Yes — if the boiler is classed as a domestic appliance (usually under 70kW), you can work on it, even inside a commercial building. But the wider system may still require a commercial qualification.
Is it worth moving from domestic to commercial?
It depends on your goals. Commercial brings higher pay and more technical challenges, but it also means extra training costs, more responsibility, and often less independence compared to running a domestic-only business.
Can I be both domestic and commercial registered?
Yes — many engineers hold both sets of qualifications, which maximises flexibility and job opportunities.