What is a defining characteristic of complex residential buildings?

Large multi-family dwellings are indeed a defining characteristic of complex residential buildings because they encompass a wider variety of living spaces, often designed to accommodate multiple households within one structure. These buildings can range from townhouses to mid-rise apartment buildings, reflecting a higher density of residents compared to single-family homes. This characteristic allows complex residential buildings to address diverse housing needs in urban areas, where space is limited.

Other types of residential structures, such as high-rise apartments, may also be a part of the category of complex buildings, but they are not exclusively defined by their height or singularity in design. The presence of complex HVAC systems is often necessary in these larger dwellings to effectively manage heating, ventilation, and air conditioning for multiple units, contrary to the notion that complex buildings do not use such systems. Thus, the characteristic of including large multi-family dwellings is essential to understanding what defines complex residential buildings.