Rooftop units and split systems handle most small buildings. Once you get to hospitals, high-rises, universities, factories and data centers, the cooling usually comes from a central plant: one or more chillers making cold water that gets pumped to air handlers throughout the building. A chiller technician keeps that plant running. It is one of the most technical specialties in commercial HVAC, and one of the hardest to staff.
This guide covers what chiller techs do, the path into the specialty, why demand is rising, and what to look for in an employer.
What a chiller is, in tech terms
A chiller is a refrigeration machine that cools water (or a water-glycol mix) instead of air. The chilled water travels through piping to coils in air handlers and fan coils, and the heat it picks up is rejected outdoors, either directly through air-cooled condenser coils or through a condenser water loop and cooling tower on water-cooled machines.
The same refrigeration cycle you learned on residential equipment applies. Everything is just bigger, with more controls, more safeties and more consequences when it goes down. A failed residential condenser means one uncomfortable house. A failed chiller can mean a hospital wing, a server hall or an entire office tower without cooling.
What a chiller technician does
A Johnson Controls posting for a data center chiller journeyman gives a good picture of the scope. The duties it lists include:
- Routine and preventive maintenance on chillers, boilers, pumps and auxiliary equipment.
- Diagnosing and repairing chiller failures using refrigeration principles and electrical schematics.
- Startups, troubleshooting, and tear-down and rebuild of chiller units.
- Integrating chillers with the building automation system.
- Mentoring other techs on chiller work.
- Advising customers during commissioning and service, including quoting repairs and upgrades.
Notice the range. In one week a chiller tech might run a seasonal startup, chase an intermittent safety trip through the control panel, supervise a compressor rebuild, and sit down with a facility manager to explain why a machine needs major repair.
Chiller work vs. general commercial service
| General commercial service | Chiller technician | |
|---|---|---|
| Typical equipment | Rooftop units, split systems, small water-source heat pumps | Air-cooled and water-cooled chillers, cooling towers, pumps, plant controls |
| Water side | Rarely involved | Central to the job: flows, temperatures, condenser water, towers |
| Repairs | Swap the part, recharge, restart | Can include major teardowns and rebuilds over several days |
| Controls | Unit controls and thermostats | Microprocessor chiller controls plus BAS integration |
| Training | General HVAC/R | General HVAC/R plus factory training on specific machines |
| Downtime stakes | Moderate | High: whole buildings and critical facilities depend on it |
How to become a chiller technician
Nobody walks out of trade school and into a chiller plant. The usual path looks like this:
- Get your foundation. HVAC/R schooling or an apprenticeship, plus EPA 608 certification. The Johnson Controls posting requires a universal EPA refrigerant certification, along with any state or local licensing that applies.
- Move into commercial service. Rooftops, splits and smaller systems teach you commercial controls, three-phase power and working in occupied buildings. If you are still residential, read our residential vs. commercial comparison.
- Get near the big equipment. Volunteer to assist on chiller startups and preventive maintenance. Many shops pair a newer tech with a senior chiller tech for exactly this.
- Earn the experience requirement. The Johnson Controls journeyman role asks for at least three years of hands-on work with air-cooled or water-cooled chillers or large rooftop ducted units.
- Get factory trained. Manufacturers train techs on their own chillers. The Johnson Controls posting highlights factory certification through its internal Service Technical Academy. This is where you learn the specific controls and procedures for a given machine.
Why data centers are pulling chiller techs
The BLS outlook for HVAC mechanics projects 11 percent employment growth from 2025 to 2035, much faster than the 3 percent average for all occupations. Among the drivers it names: commercial construction including data centers, and more sophisticated climate-control systems. BLS also expects about 40,600 openings a year on average, most of them from replacing workers who retire or change careers.
Data center cooling plants run around the clock and cannot tolerate long outages, so operators want techs who can keep chillers running and recover quickly when one fails. The Johnson Controls role above sits on a dedicated data center service team. For a tech willing to learn the equipment and work in a mission-critical setting, this is one of the strongest pockets of demand in the trade right now.
Chillers and the refrigerant transition
The refrigerant phase-down is not only a residential story. EPA's Technology Transitions restrictions by sector set a 700 GWP limit for new comfort-cooling chillers starting January 1, 2025. Industrial process chillers get later dates depending on leaving fluid temperature: January 1, 2026 for those at or above minus 30 degrees Celsius, and January 1, 2028 for the minus 50 to minus 30 range.
For a working chiller tech, that means new installs will use lower-GWP refrigerants, while the existing fleet keeps running on what it was built with. You will need to know both, follow each manufacturer's procedures, and keep your refrigerant handling records clean. If you also service residential gear, our A2L refrigerant guide covers that side of the transition.
Skills to build now if you want chiller work
You do not need to wait for a chiller job to start preparing. These are the skills that make a commercial tech the obvious pick when a chiller seat opens:
- Three-phase electrical troubleshooting. Large compressor motors, starters and drives are part of every chiller. Get comfortable reading power and control schematics on commercial equipment.
- Water-side thinking. Learn to read entering and leaving water temperatures, check flow, and understand how pumps, valves and cooling towers affect what the chiller sees. Many chiller "problems" start on the water side.
- Log reading. Chiller controls store alarms and operating history. Techs who can read that history solve intermittent problems faster than techs who only look at the machine in its current state.
- BAS fluency. The Johnson Controls posting lists chiller-to-BAS integration as a core duty. Knowing how the building automation system commands the plant helps you separate a chiller fault from a controls fault. Our building automation career guide covers that side.
- Patience with procedure. Teardowns and rebuilds are step-by-step work where skipped steps get expensive. A tech who documents carefully and follows the manufacturer manual gets trusted with bigger jobs.
- Customer communication. The same posting expects chiller techs to advise customers and quote repairs. Being able to explain a major repair in plain language to a facility manager is part of the job.
Chiller technician pay and what to look for in an employer
BLS does not break out chiller techs separately. They fall under HVAC mechanics and installers, whose median pay was $61,010 in May 2025. The top 10 percent earned more than $95,210, and the wholesale trade industry, where many manufacturer service operations sit, had a higher median ($71,190) than contractors ($60,030). Experienced chiller techs generally sit toward the upper part of the range, but there is no reliable public data to put a number on that, so compare local postings.
When you evaluate a chiller job, look past the rate:
- Factory training: Does the employer send you to manufacturer schools, and on how many product lines?
- Mentorship: Will you work alongside a senior chiller tech before you are on your own?
- Vehicle and tools: The Johnson Controls posting includes a company vehicle, tools and uniforms. That is worth real money.
- On-call and travel: Critical facilities mean emergency calls. Ask how the rotation works and how far the territory reaches.
- Equipment mix: A shop that touches many chiller brands builds broader skills than one that services a single line.
Bottom line
Becoming a chiller technician is one of the best long-term moves in commercial HVAC if you like big machines, deep troubleshooting and high-stakes work. The path takes years: a solid HVAC foundation, commercial service experience, around three years near chillers and large equipment, and factory training. Demand from data centers and complex commercial buildings gives the specialty staying power. Pick an employer that will invest in your training, and you will be building a skill set that is hard to replace.