Chiller Engineer

A chiller engineer installs, services, repairs and commissions the large refrigeration and cooling plant that keeps buildings, factories and data centres at the right temperature. Chillers are the big machines that cool water or air for air conditioning and process cooling, and the work involves both the refrigeration circuit (compressors, condensers, refrigerant gas) and the electrical controls that run it. Most chiller engineers work for manufacturers, specialist maintenance contractors or facilities management companies, servicing client sites such as hospitals, supermarkets, offices, pharmaceutical plants and server halls.

Starting salary: £18k–£24k
Live graduate jobs: 3 open now
Main way in: Apprenticeship is by far the most common route into this trade
They usually ask for: F-Gas Category I certification (City & Guilds 2079 or…

Approximate graduate salary

Trainee and apprentice positions typically start at roughly £18,000–£24,000, while a qualified field engineer or a graduate entering a manufacturer's scheme is more commonly in the region of £28,000–£38,000 to start. These are approximations only and vary considerably by region (London and the South East pay more), by sector, and by how much on-call, overtime and travel is involved - the package often includes a van, fuel card, tools and an on-call allowance, which can add meaningfully to headline pay.

What you'd actually do

Driving to client sites in a company van with tools, gauges and spare parts, often covering several sites in a day or spending a full week on one large plant room
Carrying out planned maintenance visits: checking refrigerant pressures and temperatures, oil levels, compressor run hours, water flow rates, and cleaning or inspecting condensers and evaporators
Diagnosing faults when a unit has alarmed or shut down - reading controller fault codes, testing electrical components, checking sensors and pressure switches, and working out whether the problem is mechanical, electrical, refrigerant-related or a water-side issue
Recovering, handling and recharging refrigerant gas, brazing pipework, pressure testing and evacuating systems - all of which legally requires an F-Gas handling qualification

Show 3 more

Commissioning newly installed chillers: setting up the controls, running the unit through its operating range, proving safety devices work and handing over to the client with documentation
Writing up service reports and risk assessments, logging refrigerant quantities for compliance records, and recommending remedial work or parts replacement to the client or account manager
Being on an out-of-hours call-out rota at many employers, since a failed chiller in a hospital or data centre is an emergency

How graduates get in

Apprenticeship is by far the most common route into this trade - refrigeration and air conditioning engineering apprenticeships (typically Level 2 then Level 3) combine on-the-job training with college. Many chiller engineers never went to university, and this remains the industry's default pathway.
Graduate entry does exist but is less common, and usually comes through a manufacturer's or large contractor's graduate or trainee scheme in building services, HVAC (heating, ventilation and air conditioning) or refrigeration. These schemes often rotate graduates through service, applications engineering and technical support.
Conversion from a related hands-on background: ex-Armed Forces technicians (particularly Royal Navy and RAF marine/air engineering trades), former plumbers, electricians or gas engineers frequently retrain via short commercial courses plus F-Gas certification.
Degree holders in mechanical, electrical or building services engineering sometimes enter via a design or applications role at a chiller manufacturer and move into field or commissioning engineering to build practical experience.

Show 2 more

Direct entry as a trainee or mate alongside a qualified engineer, working towards NVQ and F-Gas qualifications while employed - some contractors will take on a graduate this way, though pay starts lower and you are learning a trade from the ground up.
Higher or degree apprenticeships in building services engineering are a middle route that leads towards design and consultancy as well as plant-side work.

What employers ask for

F-Gas Category I certification (City & Guilds 2079 or equivalent) is a legal requirement to work on refrigerant-containing systems in the UK. Employers will either expect you to hold it or will fund it early on - you cannot work unsupervised on a chiller without it.
An NVQ Level 2 or 3 in refrigeration and air conditioning, or an equivalent apprenticeship completion, is the standard trade qualification. Many employers treat this as more important than a degree.
Where a degree is asked for, it is normally mechanical engineering, building services engineering, electrical engineering or a related applied science. Degree subject genuinely matters here - a non-technical degree is a weak fit unless paired with trade qualifications.
A full UK driving licence is close to universal, because the job is site-based and you will be given a van.

Show 2 more

Electrical competence for the controls side - 18th Edition wiring regulations and/or a City & Guilds electrical qualification is commonly expected or encouraged, as modern chillers are as much about controls and inverters as refrigeration.
Site safety cards (CSCS or similar), and for some sectors additional clearance - data centres, pharmaceutical plants, defence sites and NHS estates may require DBS checks, security vetting or site-specific inductions.

Skills that matter

Refrigeration cycle understanding

Almost every fault diagnosis comes back to reading superheat, subcooling and pressures correctly and working out what the numbers are telling you about the circuit.

Electrical fault finding

A large share of chiller breakdowns are electrical or controls faults rather than mechanical, so you need to be comfortable with a multimeter, contactors, sensors and variable speed drives.

Brazing and pipework

Repairs frequently involve cutting out and replacing components and making leak-free joints under nitrogen, which is a physical skill that takes practice to do reliably.

Methodical diagnostic reasoning

Under pressure on a live site, you need to eliminate causes in a logical order rather than swapping parts and hoping, because wrong guesses are expensive and visible.

Customer-facing explanation

You are usually alone on a client's site explaining to a facilities manager why their plant failed and what it will cost, often while they are under pressure from their own management.

Record-keeping and compliance awareness

Refrigerant logs, F-Gas records and service documentation are legally significant, and sloppy paperwork creates real liability for your employer.

Putting these on a CV? We counted which skills 12,914 live graduate adverts ask for, and what to do with the answer — part of our application advice.

Where it leads

Trainee or improver engineer working under supervision while gaining F-Gas and NVQ qualifications - length varies a lot, from around a year for someone with a strong technical background to the full span of an apprenticeship.
Qualified field service engineer working independently on a patch of sites, with growing specialism in particular manufacturers' equipment or in larger centrifugal and screw chillers.
Senior or specialist engineer - commissioning engineer, technical support, or large-plant specialist. Commissioning and overseas or travel-heavy roles typically pay more.
Supervisory and office-based routes: service supervisor or contracts manager running a team of engineers, technical trainer, applications or sales engineer at a manufacturer, or moving into building services design and consultancy if you hold a degree.
Longer term, some engineers become self-employed contractors or set up their own maintenance businesses, where earnings depend heavily on the client base you build. Others pursue chartered status through a route such as IEng or CEng via a relevant institution, which suits those moving towards design, energy or management roles. Timelines here vary widely and depend more on the employer's size and your willingness to move around than on fixed milestones.

What people get wrong

“It is essentially an air conditioning repair job.”

Domestic and small commercial air conditioning is a different and generally lower-paid end of the trade. Chillers are large plant - often hundreds of kilowatts to megawatts of cooling - serving critical infrastructure, and the work overlaps with water treatment, pumps, controls systems and energy performance.

“A degree is the obvious way in.”

This is predominantly a trade-qualified profession and the apprenticeship route is the mainstream path. A graduate with no practical qualification may start below an apprentice who finished three years ago, and will still need F-Gas certification before doing much useful work.

“It is a steady nine-to-five maintenance job.”

Much of the value sits in breakdowns, and breakdowns do not keep office hours. Call-out rotas, early starts, shutdown work over weekends and bank holidays, and occasional nights away are normal at many employers - which is also why on-call allowances and overtime can make a sizeable difference to actual earnings.

“The technology is static and the skills do not change.”

Refrigerant regulation is shifting fast away from high global-warming-potential gases towards lower-GWP and natural refrigerants such as ammonia, CO2 and hydrocarbons. These bring different pressures, toxicity and flammability considerations and require additional training, so experienced engineers are continually recertifying.

Where this varies

The job looks quite different depending on who you work for. At a chiller manufacturer you tend to work on one brand of equipment in depth, with strong factory training and often national travel. At a general maintenance or facilities management contractor you see many brands and may also be expected to cover air conditioning, heat pumps and other building plant. Critical-environment sectors - data centres, pharmaceutical manufacturing, hospitals - run tighter procedures, more paperwork and stricter access control, and often pay a premium for the responsibility. Industrial process refrigeration (food production, cold storage) is a distinct specialism, frequently using ammonia, and requires separate training. Geographically, work is concentrated where large buildings and industry are, so rural-based engineers usually cover very wide patches with more driving.

See all 3 live Chiller Engineer jobsFrom employers' own careers sites, updated daily Tailor your CV for this roleFree with an account, 3 a month

General guidance about the role across the UK market, not about any specific employer. Entry routes and requirements vary — always check the individual job advert.