1. For some countries with good air quality and areas with moderate temperature and humidity (such as New Zealand and Australia), one-way ventilation systems can be considered, and the relative price is relatively low.

2. For some places with serious haze and air pollution such as Pakistan and India, you can consider a two-way flow ventilation system or a ventilation system with a preheater.

3. For areas with relatively high relative humidity such as Brazil and Malaysia, when choosing a ventilation system, you need to have a dehumidification module or a ventilation system that integrates dehumidification and ventilation.