# High-Rise Social Housing in Hot-Humid Climates: Towards an 'Airhouse' Standard for Comfort
## 4 Discussion  
The two fieldwork campaigns have successfully identified the actual indoor comfort deficiencies in high-rise social housing in Kuala Lumpur. Obviously, by allowing outside air circulation, hot and polluted air enters into indoor spaces. In addition, the location of the studied buildings introduce obstructions, hindering air movement. The fieldwork studies have allowed the identification of the four issues that need to be addressed to achieve indoor comfort in high-rise social housing buildings in Kuala Lumpur: (1) The reduction of air temperature, (2) the reduction of humidity, (3) the filtering of airborne particles, and (4) to providing adequate and constant air movement. Building regulations in Malaysia, especially for high-rise residential buildings, only emphasize natural ventilation strategies. They are only concerned about the proportion of windows (Clauses 39) and size of lightwells (Clauses 40) and do not explicitly consider the health and comfort of the building occupants. The results of the fieldwork clearly indicate that the current building regulations are not  
Figure 15: The second simulation model in Integrated Environmental Solutions (IES). adequate to achieve indoor comfort by natural means in these buildings. They should be revised to take into consideration the critical conditions as well as allow for passive and low-energy strategies to constantly provide air movement, reduce the airborne particulate matter, operative temperature, and humidity levels in indoor spaces. The proposed integrated DHPAC and DHCBC system fitted in ceilings is an initial exploration about possible systems which could help to improve indoor thermal comfort and air pollution in these buildings, also reducing carbon emissions. The two systems could run separately, according to the occupant's needs. The DHAPC, which requires energy for the fans, is the main system and can reduce approximately 16% of heat and moisture and 90% of airborne particles, with a constant airflow rate. The DHCBC is a supporting system to provide approximately an additional 10% reduction in temperature and humidity, so the recommendation would be to use it during the hottest times of the day only. It is important, however, to note the limitations of the research. First of all, the research has been carried out using a limited amount of data and specific systems have been tested. Although the fieldwork was carried out in Kuala Lumpur, the physical model experiments were carried out in the UK, and, thereafter, their outcomes affected by different climate conditions. Every effort has been made in reproducing the real conditions, but we have to consider the substantial difference in local ambient humidity, where in the UK, RH is between 30% and 50%, whereas in Kuala Lumpur it is between 70% and 90%. Higher reduction rates for humidity could have been achieved if the experiment was carried out in Malaysia. Occupant behaviour is also a critical issue. While the system is in operation, the spaces should be airtight to achieve the best results, so windows have to be kept closed. There is clear thermal discomfort at the moment in these buildings and three common additional elements (awnings, fans, and air conditioning systems) are commonly installed by the occupants to overcome the problem. It was observed that at the side facing the corridor, occupants tend to install curtains and blinds and shut their windows at all times due to privacy reasons. Even if the windows that face open areas were left opened (with the opening areas reduced by the curtains and blinds), the airflow rate was still inadequate to remove heat, moisture, and particles away from the internal spaces. The PM10 and PM2.5 concentrations in indoor spaces in the high-rise social housing were recorded to be high (53.5 \(\upmu\)g/m\({}^{3}\) and 44.2 \(\upmu\)g/m\({}^{3}\), respectively), surpassing the WHO 24-h limits.