The total area of solar collectors installed in Taiwan had exceeded 2 million square meters by the end of 2010. However, there were only 98 systems in operation with area of solar collectors installed exceeding 100 square meters from 2001 to 2010. To increase industrial awareness of solar water heating technologies, a nursery greenhouse was chosen as the case study to evaluate its thermal performance throughout the months of May 2010 to April 2011. The results showed that the solar energy collected and heat loss during the night hours would affect the thermal efficiency, economic viability and attractiveness of a SWH. This study would provide useful information for all parties related to this market, manufacturers, potential users and policy-makers.