1.1. PERENE and the solar factor of glazing

Rules of thumbs exist for the thermal design of building in the French tropical island of La Reunion. The name of this programme is PERENE — French acronym for ENErgy PERformances of buildings, but the PERENE programme focuses on the design of the envelope and the energy efficiency of active systems [1] Concerning the glazing solar protections, some requirements give the levels of performance of solar protections to be reached in term of solar factor for different orientations and different climatic zones (see Table 1). Zones Z1 and Z2 are respectively the upwind and downwind coastal zones. Zones Z3 and Z4 are respectively the Highlands zone (altitude between 400 and 800m) and the altitude zone (altitude above 800m). The requirements only concern an overhang-type shading.

As for the daylighting requirements in Reunion Island, the only document which deals with this point is the adaptation in the French overseas territories of the target "visual comfort" for High Environmental Quality standards [2] The document sets requirements in terms of daylight autonomy function of the level of performance of the target required.

Some papers of course deals with the problem of daylighting in buildings, but only few gives requirements for the high solar radiations of tropical climates. The studies mainly focused on moderate climates and use methods of calculation that ar not appropriate to Reunion Island.[3], [4].