*2.3.4 Indoor Environmental Quality*

The Indoor Environmental Quality (IEQ ) category such as in LEED standards was created to provide comfort, well-being, and productivity of occupants. The IEQ requirement provides comfort, well-being, and improve the productivity of occupants [41]. The objective of this principle is to provide a healthy, comfortable and productive indoor environment for building occupants and visitors. The building design affords the users the best possible conditions in terms of indoor air quality, ventilation, and thermal comfort, access to natural ventilation and day-lighting and effective control of the acoustical environment. Human beings spend more than 90% of their time indoors while 87% is spent at home [37].

A careful integration of daylight and electrical light sources improves the lighting quality and energy performance of a structure giving a performance luminous environment. A green building provides opportunity for Personal temperature and airflow control over the HVAC system backed. A properly designed green building envelope increases the building's thermal quality [42]. A well-insulated and tightly sealed building envelope reduces moisture problems. Adequate ventilation is thus necessary to eliminate moisture from sources indoors and prevent incidences of sick building syndrome. A poor quality indoor environment impairs cognitive performance, negatively impacts occupant's health, and reduces performance [43, 44]. However, [45] reported low quality of houses and its services in the government estates.

The impact of global climate change in Nigeria include reduced rainfall, shorter period of the raining season, long term increase in temperature in most part of the country; the extreme northeast, extreme northwest and extreme southwest. The average temperatures increased by 1.4–1.9°C. Heat waves from this phenomenon is expected to be on the rise resulting in hot nights. Hot night is where night time temperatures are in the top 10% experienced by a region. Advances in extreme heat particularly is a threat to millions of Nigerians without access to electricity or air conditioning. 92 in every 1000 people in the urban areas and just 14 in every 1000 in rural areas have access to air conditioning. Future housing must provide for quality indoor environment.
