## 5 Conclusions and Recommendations  
To conclude, the results of this study achieved two objectives that were set at the beginning of the research. Objective 1 successfully determined students' satisfaction and perception levels on the classrooms' indoor environment aspects. The results of measurements and analysis conducted have found that visual comfort (3.9987) illustrates the highest mean, followed by cleanliness (3.6675), air movement (3.6257), noise pollution (3.1597), and thermal comfort (2.2435). From the data collected, it can be concluded that the mean of overall comfort is 2.1663, which illustrates that the current comfort level of classrooms is still under the lowest implementation and needs to be improved. Thermal comfort which achieves the lowest mean is influenced by the hot and humid climate in Malaysia throughout the year in addition to the aspects of facilities provided in the classroom. Since the case study was conducted in a public-school building, no air conditioning facilities were provided, and students had to rely on ceiling fan facilities. Nevertheless, to achieve good thermal comfort in the classroom, the use of air conditioning should be implemented to ensure that students can study in a comfortable environment even with hot weather conditions based on lower the result achieve on thermal comfort. The use of ceiling fans only improves the air temperature sensation, however, at high air temperatures and humidity levels, air fans do not achieve the thermal comfort desired by students. If the use of air conditioning cannot be provided in every classroom, the school needs to find other initiatives to ensure that students can study in comfortable conditions such as moving towards green school development by planting trees as an alternative to reduce the temperature. Tree planting can reduce the heat stress of students by providing the benefits of evatranspiration cooling and shading [32]. This is because individual trees can reduce the ambient temperature between 1.1 and 2.8 \({}^{\circ}\)C in summer [33] and are able to eliminate large amounts of shortwave radiation through reflection and transmission through their leaves to reduce the ambient air temperature [34]. These initiatives are cheaper and can last for a long time as well as less maintenance is required. However, majority of the respondents feel comfortable in terms of visual comfort: artificial lighting (4.0026) and natural lighting (3.9948), quality of air ventilation (3.7277), classroom cleanliness (3.6675), and quality of air movement (3.5236). To achieve Objective 2, several methods were proposed to improve the classroom indoor environment, specifically for secondary school buildings in Malaysia. The method used was to conduct semi-structured interviews with 35 experts consisting of 17 technical and 18 non-technical respondents. Among the methods proposed in increasing physical satisfaction during the learning process are having a limitation on the classroom capacity, additional unit of mechanical ventilation, enhance the building openings, standardize the quality of building materials, ensure an accurate illuminance level of artificial lighting, control the cleanliness, and schedule school building maintenance. To conclude this study, it can be said that POE has a substantial impact on improving building performance. This study only focuses on classrooms at public-school buildings specifically from two approaches; the first is by collecting and tabulating feedback on the current condition of classrooms at secondary school buildings which lead to awareness by the schools' building management. From the data collected, it is clear that the quality of classroom indoor environment needs to be improved to ensure the comfort of learning spaces, more so for students who spend more than 5 h in classrooms. Secondly, this study provides a benchmark for classroom comfort levels at secondary school buildings that can be used to enhance building evaluation by considering occupants' or users' sensitivity.