# High-Rise Social Housing in Hot-Humid Climates: Towards an 'Airhouse' Standard for Comfort
## 4 Discussion
As explained above, the first 'airhouse' standard proposal was based on natural ventilation, promoting air movement using passive elements such as opening ratios according to altitude, the hierarchy of opening design and effective plan layout to achieve thermal comfort [4]. The new research explores the use of an integrated strategy of using dynamic insulation with a hybrid ventilation with a radiant cooling ceiling, which could also improve the indoor air quality and active lightwells. In general, all the new results are lower than the previous ones (Table 7). For the thermal comfort conditions, the new recommendation for air temperature is set between 23 to 24 \({}^{\circ}\)C, where the previous value was 25 to 27 \({}^{\circ}\)C. For humidity, a 5% improvement is suggested, from a maximum of 60% RH to 55% RH, and for air movement, it has been reduced from 0.3 to 1.5 m/s, to a minimum of 0.125 m/s. Concerning indoor air quality, the values for PM10 and PM2.5 should be no more than 1.2 \(\upmu\)g/m\({}^{3}\) and 1.0 \(\upmu\)g/m\({}^{3}\), respectively. For energy consumption and carbon emissions, the recommendations have been substantially reduced, namely, from less than 5000 kWh/year and 2500 kgCO\({}_{2}\)/year, respectively, to less than 700 kWh/year and 200 kgCO\({}_{2}\)/year. The series of physical experiments and computational simulations demonstrate that DHAPC is capable of filtering heat, moisture, particulate matter, and toxicant gases, while DHCBC can further reduce air temperature and humidity. As a result, cool and clean air could be supplied into indoor spaces with a constant and adequate airflow rate. This result will improve indoor comfort and air quality and solve the problems of indoor discomfort and indoor air pollution. However, even though this research has combined both physical and computer modelling, the validation of the system should be done using prototypes in actual hot-humid climatic contexts. The system could be fitted not only in new buildings but also in existing ones. It requires a minimum depth of 600 mm at the ceiling space, which is presently available. Although the UBBL (Clause 44, 1a) sets 2500 mm as the minimum height of living rooms and bedrooms [5], they have commonly been built higher, usually between 3000 and 3500 mm, in order to allow ceiling fans to be installed, as they are considered as a basic requirement in buildings in Malaysia. However, all the buildability issues and implications of the system need to be taken in account and carefully consideration has to be given to fire control and maintenance aspects. It should also be noted that the energy savings obtained were simply estimated by calculating the electricity consumption of a chilled water loop system with supply and extract fans employed in a number of rooms only. A very detailed analysis of the electricity consumption and its potential savings is a very significant task, given the large number of variables involved. In this regard, this task was considered beyond the scope of the present study. Fans would need to be provided for supplying cool, clean, and constant air into indoor spaces and to assist the removal of the air efficiently inside the lightwell, consuming energy and producing emissions. Fans also require extensive maintenance, in particular, the DHAPC system's fans, ducts, and filter membranes, which, considering the pollution levels in Kuala Lumpur, would need to be cleaned at least every six months in the case of the fans and every year for the ducts to ensure hygienic levels. Consideration has to also be given to the cleaning and disposal of the filter membrane and the contaminants deposited in it. Overall, this is an additional system to be added to the building, and it can be added in any building, however, the priority should always be the adequate location, design, and construction of the buildings, so that the air movement is enhanced, maximizing the specific conditions found in high-rises.