Air-cooled chillers
- Usually installed outdoors, often on the roof
- No cooling tower, so no tower water treatment or Legionella obligations for the chiller
- Simpler plant and lower maintenance
- Less efficient than water-cooled plant, especially in hot weather
- Common in small and medium buildings
Water-cooled chillers
- Installed indoors in a plant room, with a cooling tower and condenser water pumps
- More efficient, particularly at large capacities
- Use water through cooling tower evaporation and need water treatment
- Cooling towers carry state health obligations for Legionella control
- Common in large office towers, hospitals and shopping centres
Which is right for your building
It depends on the cooling load, the space available, energy targets and what is already installed. Converting from water-cooled to air-cooled at replacement time can remove a cooling tower and its compliance work, but needs roof space and structural capacity and may cost more to run. A specialist can compare both for your building.
Chiller replacement
End-of-life, R22 and inefficient chillers replaced, from selection and crane lift to commissioning. See chiller replacement →
Updated 2 November 2026. General information only; your specialist will advise on your plant.