What do you mean by opening doors and windows horizontally?

Flat doors and windows refer to the opening form of doors and windows. Doors and windows can be made flat inside or hung outside. Horizontal opening and push-pull only refer to the opening of doors and windows.

The casement window has the advantages of large opening area, good ventilation, good sealing, sound insulation, heat preservation and good impermeability. It is convenient to clean windows with internal opening; Open does not occupy space when opened. The disadvantage is that the window width is small and the field of vision is not wide. The outer window occupies the space outside the wall and is easy to be damaged when it is windy; The inner window takes up some indoor space, so it is not convenient to use the screen window. It is also inconvenient to use screens and curtains when opening windows. If the quality is not up to standard, it may leak rain.