Under ideal conditions, if the attic is well ventilated and its floor heavily insulated, heat absorbed by the roof may be exhausted. Unfortunately, most homes have less than ideal conditions. A study by Lawrence Berkeley laboratory reveals that increasing the reflectivity of roofs and other surfaces in metropolitan areas could dramatically reduce energy costs nationwide. The colors used inside a residence or workplace can also save on energy costs. The same principle, the lighter the color the higher the reflectivity can be applied.
Dark walls absorb more light and reflect less.
Consequently, far more lighting is required for rooms with dark walls than those with light walls. In addition to the walls, it is a good idea to keep the ceiling light and bright for good reflectance. Therefore, the higher the LRV number of the paint color, the less artificial light you will need. This causes excessive stimulation and irritation of the eyes. Eye fatigue will follow.