A simple building is one in which the building services are mostly of modest capacity and delivered locally, with the building services being mainly independent of other systems in the building fabric and avoiding sophisticated control systems. This type of building is commonly found in developing countries where cost-effective solutions are required that do not require extensive infrastructure investments. In comparison, a complex building is one that uses more advanced technology for heating, air conditioning, and water treatment because it needs to function efficiently and comfortably. These buildings usually have a longer life expectancy than simple buildings because they are built using better materials and techniques. They may also be located in better locations with good access to public utilities like power lines and roads. Simple buildings are most common in areas without much industry or traffic, while complex buildings are used in cities and larger towns. Simple buildings use such methods as burning wood or coal for heat and electricity and collecting rainwater for drinking purposes. They may also have an outdoor toilet or none at all. Complex buildings rely more heavily on electricity for heating and cooling as well as pumping water from deep wells for usage outside of rainfall events. They may have indoor toilets that use chemicals to treat wastewater before disposing of it into local sewer lines. There are several factors that determine if a building will be considered simple or complex.