Cooling capacity is one of the key parameters to consider when selecting a central air conditioner. It directly determines whether the central AC can effectively cool down the space. The size of the cooling capacity should be determined based on the area to be cooled. Generally, the cooling capacity should be calculated at a standard of 10-20W per square meter. For instance, if a room measures 30 square meters, the central AC's cooling capacity should be between 3000-6000W. It's worth noting that selecting a central AC with an oversized cooling capacity does not necessarily result in better cooling performance; instead, it may waste energy and increase operational costs. Energy efficiency ratio is another parameter to pay attention to when choosing a central air conditioner. The energy efficiency ratio refers to the ratio of the electrical energy consumed by the air conditioner to the cooling capacity. A higher energy efficiency ratio indicates that the air conditioner consumes less electricity for the same cooling capacity, leading to lower operational costs. Therefore, when selecting a central air conditioner, it is advisable to choose a model with a higher energy efficiency ratio.