A typical compressor-based or static cooling system receives a temperature set-point from the host tool. The system maintains this temperature set-point in its reservoir by cycling the compressor and heater on and off. The fluid is pumped to the chamber at the set-point temperature from its remote location. Heat losses between the unit and chamber are substantial and vary from installation to installation. As a result, wafer chuck temperatures will fluctuate because the static system is only capable of maintaining a constant temperature in its reservoir.