Abstract
A key approach to protecting historic buildings is adapting them for public use, which requires choosing suitable functions and making appropriate modifications. While exteriors should be preserved to maintain historic value, interiors must offer functional, modern spaces. Beyond design of the building and building materials, the indoor environment, especially daylighting - is crucial. Higher daylight levels reduce energy demand for artificial lighting. This paper analyzes a historic lecture hall from the last century located on the campus of the Technical University of Košice. Although the building is used daily and its space is efficiently organized, daylight in the auditorium is significantly limited. The study evaluates real measured data, later validated through simulation tools, and compares the resulting values. It further explores the benefits of improving visual comfort by enhancing daylighting. Proposed interventions include adding new openings such as windows, light guide, or skylights. Simulated variants demonstrate substantial improvement, achieving the recommended average daylight levels.