As per the National Building Code of India 2005.

As per the National Building Code of India 2005, the height of all rooms for human habitation

shall not be less than 2.75 m measured from the surface of the floor to the lowest point of the ceiling

(bottom of the slab). In the case of a pitched roof, the average height of rooms shall not be less than 2.75 m.

The minimum clear head room under a beam, folded plates or eves shall be 2.4 m. In the case of air-conditioned

rooms, a height of not less than 2.4 m measured from the surface of the floor to the lowest point of air-conditioning

duct or the false ceiling shall be provided. For kitchens it is 2.75m, bathrooms 2.1m, lofts 2.2m,

mezzanine floors 2.2m, store rooms 2.2m, and basements 2.4 m.

The ceiling heights for educational buildings is 3.6 m (cold regions 3m) and forindustrial buildings it is 3.6 m

(when air-conditioned, 3 m). Architects design rooms and halls keeping in mind the volume of space, ventilation

and natural lighting requirements and not just the plan sizes.

One has to visualise it in three dimensions before finalising the heights.

A building can have same ceiling height throughout or it can have higher heights for living areas

by providing split levels and double heights.

A lot of research and survey has been conducted the world over to decide on the ceiling heights!

It all finally depends on the comfort of the user.