植栽能有效降溫，對建築物能源使用有一定的正面影響。國外關於綠屋頂對建築物能源經濟效益方面的研究很多，但國內對於綠屋頂對建築物能源影響的研究主要多集中在實測溫度表現，對於建築物能源影響效益的討論較少。本研究實測三場連續12小時的屋頂表面溫度變化，包括一般屋頂、土壤、台北草、佛甲草，並使用建築熱物理基礎的總熱通量公式，計算綠屋頂與一般屋頂的熱通量差異，以此作為對建築物能源影響的基礎。實測結果發現，與環境溫度相比，在中午最高溫時，一般屋頂表面會比環境溫度高出11.8度，但佛甲草表面溫度比環境度低上5.4度。在最低溫時一般屋頂比環境溫度高2.8度，但佛甲草表面溫度比環境溫度低4度。一般屋頂表面的平均熱通量為114.2W/m^2，而佛甲草表面的熱通量為-57.7W/m^2。結果顯示，屋頂植栽對表面溫度有降溫以及減少環境溫度變動的效果，且綠屋頂的熱通量方向與一般屋頂不同，應可幫助建築物降溫，進而減少建築物內部的能源使用。
Vegetation can effectively reduce ambient temperature and have positive impact on building energy usage. The building energy saving has been received many attentions. In Taiwan, researches are focus on temperature measurements of vegetation on roofs, but it is rarely to investigate further on the effects of building energy. No studies are seen in quantify the energy savings from roof vegetation. This study measured temperature consecutively for four roof surfaces in 12 hours. The surfaces are included ordinary rooftop, soil, Manila Grass and Sedum Lineare. The total heat flux formula is used to calculate the difference of heat flux between green roofs and ordinary roof. Compared with the ambient temperature, the results showed that the surface temperature difference of ordinary rooftop was the most highest about 11.8°C, and Sedum Lineare was lower than the ambient temperature about 5.4°C. Moreover, the ordinary rooftop was only higher 2.8°C than the ambient temperature at night, and Sedum Lineare was lower 4°C than the ambient temperature. In addition, the average surface heat flux of ordinary rooftop was 114.2W/m^2 and Sedum Lineare was -57.7 W/m^2. The results showed roof planting can reduce the surface temperature fluctuation, and the heat flux direction of green roofs are opposite to the ordinary rooftop, implying that green roofs can moderate the energy use of buildings.
