Should You Buy a Fresh-Air Air Conditioner? How Is It Different from a Conventional Unit?

Many people wonder why they feel groggy after running a conventional air conditioner for a long time, or why the room begins to smell stale and has to be aired out. One major reason ventilation is emphasized in air-conditioned rooms is that closed doors and windows can allow indoor concentrations of carbon dioxide and formaldehyde to rise. Whether cooling or heating, a conventional air conditioner simply recirculates indoor air. The fan on the outdoor unit may appear to move air, but its purpose is only to help raise or lower the temperature of the evaporator or condenser. Put simply, in addition to the condensate drain and the low- and high-pressure refrigerant lines found on a conventional unit, a fresh-air air conditioner has an extra duct. This duct is what allows fresh outdoor air to enter.

Compared with a conventional air conditioner, the most noteworthy and essential function of a fresh-air model is its ability to supply users with relatively oxygen-rich air at a rate determined by its fresh-air volume. The positive pressure mentioned above is also directly related to that airflow. Most products currently on the market deliver a moderate 20–60 m³/h, which is roughly enough to ventilate a space of only 8–15 m². Although many industry professionals believe that a single positive-pressure supply of 20–30 m³/h offers limited value, simply pursuing a larger number is not necessarily the right direction for a fresh-air air conditioner. Excessive fresh-air volume can increase energy consumption and may require users to replace the filter more frequently, which can waste resources. Another important point is that increasing the fresh-air volume also requires a larger wall opening.