## 4 Conclusions  
Lighting is an important aspect in spaces where the optimal performance of visual activities must be guaranteed. This study has taken a school as a case study. Schools are composed of numerous spaces which require different qualities of light inside them. The chosen school is located in a small town in the southeast of Italy and is characterized by a Mediterranean climate. The school can be considered representative of the area for geometry and construction techniques. Initially, it was noted that most of the electrical consumption of this school was due to the lighting system, consisting of fluorescent luminaires with manual on and off switching. This study proposed a methodology to enhance retrofitting strategies to compensate for daylight and therefore not overestimate the light inside the rooms. Several scenarios have been proposed. First, the existing lamp system was replaced with a system of LED luminaires designed for each room of the school. Once the replacement of fluorescent luminaires was defined, the following options, focused specifically on LED lighting management, were proposed:  
* Case 1--Manual on/off switch-on  
Figure 7: Energy consumption, economic saving, and LENI of all scenarios. * Case 2--LED lamp dimming with single modulation
* Case 3--LED lamp dimming with modulation for rows of luminaires  
The three cases were analysed both from technical and economic points of view, assessing compliance with the current regulations. The data useful to determine the values of daylight and artificial lighting were obtained through the use of software, starting with Google SketchUp for the school modelling and calculation grid positioning. Daysim was used to derive the values of illuminance due to daylight for each room, and Dialux Evo was used to design the artificial lighting. By analysing the data obtained, it was observed that with the simple replacement of fluorescent luminaires with LED luminaires, there was a high level of energy saving. The results showed a reduction in energy consumption compared with the current state of 33% (case 1), 52% (case 2), and 95% (case 3), respectively. Overall, case 3 (Lamp dimming with modulation for rows of luminaires) resulted in reduced energy consumption, increased economic savings, and a reduced LENI. It has to be emphasized that LED technology has some disadvantages. One of them is related to their delicate power electronics. For this reason, the LED lamps having high sensitivity to forward current is a double-edged sword. It gives lighting systems superior controllability but also makes drive current regulation enormously challenging. Another problem is the dissipation of heat. If the device junction temperature is not maintained below a set limit, this may accelerate the kinetics of failure mechanisms and generate degradation of the components of the fixtures. These disadvantages can cause failure problems and, consequently, an increase in costs. The latter was not considered in the economic analysis presented in this paper. Moreover, it must be emphasized that the reactive power was not considered in the final cost of electricity for simplicity. This is because this is relevant mainly in the case of outdoor lighting systems. If the contribution of the light load to monthly consumption is not so high, then an increase in the absorption of reactive power is not able to significantly change the average monthly power factor, for which the penalties are calculated for the users of the electricity system. Based on the results obtained from this work, it is clear that designing a structure that favours the entry of daylight into the rooms as much as possible brings considerable energy and economic savings. Future studies could take interest in the building envelope to further reduce the economic consumption regarding summer and winter air conditioning. Conceptualization, C.B., M.B. ([PERSON]), P.M.C., and M.B. ([PERSON]); methodology, C.B., M.B. ([PERSON]), P.M.C., and M.B. ([PERSON]); software, C.B., M.B.