The Role of Attic Ventilation to Reduce Indoor Air Temperature in Zinc-Roofed Buildings in a Humid Tropical Climate

—Many buildings were built using zinc roofs in North Sulawesi province, Indonesia, there is more than 92 percent of buildings with zinc roofs. Buildings in humid tropical climates often face the problem of excessive heat due to the solar radiation accumulates, especially on roofs that can propagate into occupied spaces. The use of zinc roofs can also cause excessive heat in the occupancy space if the construction does not consider the thermal properties of the material. This article aims to assess the benefits of attic ventilation, especially in buildings with zinc roofs to cut the indoor air temperature. This research has been carried out by building two similar test cells in which one cell has roof ventilation of 20% Net Free Ventilation Area and the other cell with an airtight attic. The measurement results showed that the use of attic ventilation causes the indoor air temperature to always be lower, on average 1.2 °C. The same thing, by comparing the use of roof insulation; its use can cut the air temperature in the attic by 0.3 °C. Comparisons show that at certain hours the indoor air temperature under an insulated roof is lower than under a ventilated roof. In contrast, the overall indoor air temperature is 0.1 ° C lower on the ventilated roof. This condition is rather difficult to conclude that the use of roof insulation is better than the use of roof ventilation. Further research is still needed to examine the effect of the attic vent area on reducing the indoor air temperature compared to the use of roof insulation.