A substructure hood is a hood that you mount on the wall or under a hanging kitchen cupboard. This is a compact extractor hood that does not have a chimney and therefore fits into a smaller kitchen. Most hoods with a substructure model are available with a width of 60 centimeters. However, there are also models that are 90 centimeters wide. When you place it under your kitchen cabinet, the air goes out through the cabinet through a drain pipe.