In a temperature control system and method, a compressor is left on during steady state operation even when cooling is not needed, and an electronically controlled valve (e.g., a solenoid valve) is used to enable and disable the flow of coolant through a heat exchanger system in order to selectively control whether cooling is enabled or disabled. A flow of air may be passed through the heat exchanger system to cool the flow of air, and the valve may be controlled based at least in part on temperature of the flow of air, e.g., in accordance with a proportional-integral-derivative (PID) control scheme. A heater may be controlled to selectively heat the flow of air. A cooling cycle may be provided in which the heater is disabled and the flow of coolant is enabled via the valve, and a heating cycle may be provided in which the heater is enabled and the flow of coolant is disabled via the valve.