Fresh air and central air conditioning should be carried out before all decoration projects, but it is recommended to cut the grooves for water and electricity first. Sometimes fresh air and central air conditioning pipelines will affect the wall grooves, and some may not be able to be opened. There are two types of fresh air on the roof, one is suspended from the roof, and the other is on the ground. You need to coordinate the location of water and electricity, think about where to place the main unit, whether the suspended ceiling will affect the replacement of the filter element, and many factors. , if you don’t understand, ask again