Open skylights were used in Ancient Roman Times. Buildings such as the Pantheon in Rome have the Oculus. The Oculus is a circular opening 7.8 meters in diameter at the top of the domed roof of the Pantheon. The purpose of the oculus was to illuminate the interior of the building and to allow worshippers inside the temple to have a connection to their gods. The open skylight also allowed for ventilation in the otherwise airless space. Other ancient buildings that utilised open skylights include: Bazaar of Kashan in Iran, Duomo di Siena.
Closed or glazed skylights have been used since the Industrial revolution made huge advances in glass production. The skylights however conducted a lot of heat which was beneficial during the colder months but problematic during the warmer months. The glass was single glazed and prone to cracking and breaking in hail storms and by falling debris. This breakage was a deterrent to home owners. However, with the advancement of double glazing, skylights increased in popularity. Skylights nowadays can be more like windows in the roof with clear glass being utilised allowing for the outdoors to be indoors.
Glass tinting and blinds help meet today’s harsh environment allowing for increased light but not increased heat transfer.