If the incubator is used for field water testing or ambient-temperature environments, a heating-only system (using silicone heating film) is cost-effective. However, for applications requiring temperatures below ambient (e.g., BOD testing or yeast culture), you must select a model with Peltier (Thermoelectric) cooling technology. Peltier systems are preferred for portable units because they are refrigerant-free, lightweight, and vibration-proof, unlike traditional compressor-based systems which are prone to damage during transit.