Abstract: The outdoor condenser of air conditioning unit on the roof of a restaurant in Shanghai generates high decibel noise during operation, exceeding the standard noise value of 18.54 dB. To address this, a composite sound-insulating enclosure was designed to meet the noise reduction requirements of the condenser. Given the fact that the installation of this enclosure may lead to poor heat dissipation of the condenser, potentially affecting the performance of the air conditioner, a computational fluid dynamics (CFD) simulation was conducted to analyze the thermal environment before and after the installation of the sound-insulating enclosure. The simulation results showed that the temperature of the inlet and outlet of the condenser increased by 2.90 ℃ and 2.99 ℃, respectively, after the sound-insulating enclosure was added. It was concluded that the influence of the change of thermal environment on the equipment was within the safe and controllable range, thereby verifying the safety and feasibility of the sound-insulating enclosure from the perspective of the thermal environment.