What term describes the malfunctioning system at the workplace that caused discomfort due to cold?

The term that accurately describes the malfunctioning system in a workplace that caused discomfort due to cold is "heating." Heating systems are specifically designed to increase the temperature in an environment to provide warmth. When a heating system is not functioning properly, it can result in cooler than desired temperatures, leading to discomfort among employees.

Cooling refers to systems that reduce temperature, which does not apply in this context since the issue is related to insufficient heating. Air conditioning usually serves to both cool and dehumidify the air but does not inherently provide warmth. Ventilation instead focuses on the exchange of indoor and outdoor air, which does not directly relate to temperature management. Thus, in situations involving discomfort due to cold, the heating system is the most relevant system to consider.