I read this in the mid 80's at school, a society of people living underground, not futuristic homes. One boy not convinced the world is all like his world. Something about glowing moss or lichen.
My first reading of this question was that the story was about people living in caves or rough delvings. However, it does not actually say that, so I am going to offer (as a long shot) a book that has people living in a grungy underground metropolis instead: This Time of Darkness, by H. M. Hoover, published in 1980.
The city that young Amy and Axel live in is not futuristic. I remember be being described in a way that made me think of cheap 1970s apartments, piled one atop another, mostly constructed out of cement and plastic. What they eat is mostly vat-grown algal/fungus mush, which they microwave to heat up (everybody having their own microwave probably did seem pretty futuristic in 1980, actually) and harden, from something like gruel to an almost cracker-like consistency.
Axel is not actually from the city (and his name isn't really Axel, either). He knows there must be a way out, and he gets Amy to try to escape with him. There are some queer glows they encounter in the mechanical sections of the city, once they have climbed many floors above where they started.
The book is a young adults science fiction standard and has come up here numerous times before: