A chiller technician is the commercial HVAC specialist who keeps a building's central cooling plant running: the large chillers that cool water for air handlers, the cooling towers that reject the heat outdoors, and the controls that stage it all.
The job centers on planned service — annuals, teardowns, water treatment, controls — across employment settings that run from mechanical contractors to equipment manufacturers' service organizations.
Here's what the work involves, who hires, how to get in, and what the pay data honestly says.
What is a chiller, and where do chillers do the cooling?
A chiller is a building's central cooling plant: a large refrigeration machine that cools water, plus the pump-and-pipe network that carries that chilled water to air handlers and terminal units around the building, where it absorbs heat from the air.
The warmed water circulates back to the chiller to be cooled again.
Where a house has one condenser per system, a chilled-water plant serves many zones from one machine room.
Chillers reject the heat they collect in one of two ways.
Water-cooled chillers dump it into a separate condenser-water loop that runs out to a cooling tower, where evaporation carries the heat outdoors.
Air-cooled chillers reject it directly to outside air through coils and fans.
Inside the machine, large commercial chillers are built around centrifugal or screw compressors, with scroll compressors toward the smaller end — and the refrigerant a machine uses decides its pressure class, which shapes how it is serviced.
The customers are the big-footprint buildings: office towers, hospitals, university campuses, hotels, malls, industrial process-cooling loads, and data centers, where chilled water keeps server floors alive — see our data center HVAC guide for that specialty.
Chillers also share the plant room with the heating side: boilers and hydronic systems heat many of the same buildings in winter, and the boiler technician guide covers that half of the plant.
The machines themselves are in transition.
Under the EPA's HFC rules, chillers for comfort cooling have been limited to GWP under 700 for new installations since January 1, 2025 — refrigerant choice is regulated territory, and the certification section below explains the federal rule that governs servicing it.
What a chiller technician actually does: annuals, teardowns, controls
The calendar is built around planned service.
Chillers can sit on maintenance contracts, and the centerpiece is the annual: a yearly major service in which the technician verifies refrigerant charge and operating pressures, takes oil and refrigerant samples for laboratory analysis, cleans and inspects the heat-exchanger tubes, tests safety cutouts, and calibrates the controls that run the machine.
Between annuals come the shorter visits — logging operating data, checking water treatment, walking the cooling tower.
The teardown is the work that defines the specialty.
When oil analysis or operating data shows trouble, the machine gets opened: compressor teardowns, bearing and seal replacement, tube work on the cooler and condenser, and the recovery and charging work on the refrigerant circuit.
A teardown is a planned, quoted job — the chiller is drained, opened, inspected, and rebuilt over days, not an afternoon.
Water treatment is a genuine part of the job on tower-water plants.
Open cooling-tower water picks up scale, corrosion, and biological growth, and poor water chemistry shows up as fouled tubes and lost capacity.
Chiller technicians check the chemistry, log it, and work alongside water-treatment specialists to keep the loop clean.
Then there is the controls layer.
A modern chiller runs on its own microprocessor control panel and reports into the building automation system, which stages machines, holds chilled-water set points, and alarms faults.
A chiller technician calibrates sensors, tunes staging, and troubleshoots the controls chain — and deep building-controls work is its own role; see our HVAC controls technician guide.
The rhythm follows the cooling season.
Most HVAC technicians work full time, schedules may include evenings or weekends, they may be on call for emergencies, and peak heating and cooling seasons sometimes bring overtime or irregular schedules, per BLS.
A chiller down in July is an emergency call — and the technician who can bring it back is the one the facility manager remembers.
Manufacturer service vs mechanical contractor: who employs chiller techs
Chiller work has more than one employment setting, and the experience differs more than the job title does.
Mechanical contractors are the first setting.
Across the occupation as a whole, Building Equipment Contractors — the industry group that includes mechanical and HVAC contractors — employed 305,330 HVACR mechanics and installers in May 2025, by far its largest industry.
A contractor-side chiller tech sees many brands and vintages, may come up installing new plants alongside the shop's construction side, and then inherit those buildings as service-agreement customers.
The breadth is the education: one week a teardown on a screw machine, the next week a call in the same building's boiler room.
Manufacturer service organizations are the other door.
Chiller manufacturers run factory-authorized service networks, and a technician who joins one can specialize deeply in that maker's machines — factory training on specific product lines, the maker's own diagnostics and parts channels, and a mix of warranty, contract, and major-service work on the machines that company sold.
The depth is the education: the same compressor family, year after year, in plant rooms across the territory.
Neither door is better; they build different careers.
Contractor work trades depth for breadth and stays close to the construction cycle.
Manufacturer work trades breadth for depth on machines that carry the maker's name.
Both are field roles with on-call realities, and both draw from the same entry path — the commercial HVAC technician guide covers the wider role and the ways into it.
How to become a chiller technician
There is no chiller-school shortcut.
You become a chiller technician by entering the HVAC trade and steering toward central-plant equipment:
Learn the trade
BLS says HVAC technicians typically need a postsecondary nondegree award — programs of 6 months to 2 years — followed by lengthy on-the-job training; some technicians train through multi-year apprenticeships. Registered apprenticeships are the deep end: United Association programs, for example, combine 2,000 hours of paid on-the-job training a year with 216 hours of related classroom instruction.Get EPA 608 before you touch refrigerant
Under the EPA's rule at 40 CFR 82.161, any person who could reasonably be expected to violate the integrity of a refrigerant circuit while maintaining, servicing, or repairing appliances containing covered refrigerants must pass an exam from an EPA-approved technician certification program. Type II covers medium-, high-, and very-high-pressure appliances; Type III covers low-pressure appliances — the class that includes chillers using refrigerants such as R-11, R-123, R-113, or R-245fa. Our EPA 608 certification guide walks the exam and the types.Get onto big equipment
Take commercial route work with a mechanical contractor — light-commercial preventive-maintenance routes teach the rhythms, and the plant room teaches the machines. Ask to second on chiller annuals and teardowns, and take manufacturer training courses wherever an employer offers them.Specialize and go deep
Chillers, cooling towers, water treatment, plant controls — depth in these is what turns a commercial technician into the one a facility manager calls first, and eventually into the manufacturer-service or independent direction.
Licensing is a separate layer from certification: worker and contractor licence rules are set state by state — and city by city where licensing is local.
Our state-by-state HVAC licence guide maps the ladder.
Certification is federal; licensing is not — verify both
What chiller technicians earn — and what the data can't say
Start with what the federal data can and cannot say.
The BLS sources we checked — the OEWS occupation list and the Employment Projections table — carry no chiller-technician series: the title sits inside Heating, Air Conditioning, and Refrigeration Mechanics and Installers (SOC 49-9021), the occupation BLS counts as one.
What BLS does publish is for the combined occupation.
In the May 2025 Occupational Employment and Wage Statistics, the median was $29.33 an hour — $61,010 a year.
The spread inside the occupation is wide: the 25th percentile earned $48,360 and the 75th earned $77,060, while the 90th percentile earned $95,210 ($45.78 an hour).
The industry you work in moves the number.
Among the industries employing the most HVACR mechanics, May 2025 medians ran from $60,030 at plumbing, heating, and air-conditioning contractors to $71,190 in wholesale trade — and the small high-paying niches BLS identifies, such as computer systems design at $115,910 and scheduled air transportation at $114,080, sit far above the occupation's center.
Those are small niches, not typical jobs.
Two caveats keep the figures honest: the OEWS survey counts wage-and-salary workers only — it excludes the self-employed — and it measures base pay, excluding overtime pay, shift differentials, nonproduction bonuses, and benefits.
What employers value in the specialty is structural, not statistical: the work is teardown-heavy planned service rather than swap-and-go, and the customer is a facility manager with a budget for keeping a plant alive.
Every pay figure on this page is for the combined 49-9021 occupation — within that series there is no chiller-only number to quote.
For the national percentile tables, see the commercial HVAC technician salary page.
This page is career information, not legal or pay advice. Pay figures are BLS OEWS May 2025 for SOC 49-9021, the combined HVACR occupation. Licence requirements come from your state licensing agency, or the city/county where licensing is local — confirm with the issuing body.