A Duplex house plan has two living units attached to each other, either next to each other via townhouses or above each other like apartments Duplex Apartments are growing in popularity with the elite South Delhi crowd due to their luxurious feel, exclusivity, and privacy. Duplex apartments in South Delhi’s High-End localities are usually two units on separate floors usually joined by private internal lift or staircases and usually have separate driveway for more than 3 Cars having separate entrances. For those people who’ve lived in single floor housing for their entire life, living in duplex apartments can be pretty exciting due to expansive space.