Nozoicha Dame! ~Dokidoki Joshiryou Kansatsu~

Main character has to live alone due to parents circumstances. He rents an apartment owned by his relatives cheaply and goes to school. However, girls from school start to visit this place and renovate it little by little ending with renaming it to "Women's Dormitory". Protagonist soon finds himself living alongside many girls and bumping into them at every corner.

[From vndbreview]