In the Philippines, concrete hollow blocks (CHBs) filled with mortar are the most common walling material in residential design and construction. These are generally used without an insulating layer since insulation is made impractical by factors such as legislative constraints, cultural preferences, and the lack of established practice. As a result, uninsulated, mortar-filled CHB walls exhibit relatively high thermal conductivity which allows heat to transfer easily from the exterior into the interior. This leads to poor thermal performance, higher cooling demand, and uncomfortable indoor conditions in hot climates such as the Philippines. In addressing this thermal performance issue, these limitations emphasize the need for alternative walling materials in residential buildings that are inherently more thermally efficient without relying on added insulation.
This study aims to examine the effectiveness of rice husk ash (RHA) bricks in enhancing the thermal performance of local residential designs compared to the conventional CHB walling material. RHA bricks are produced from rice husk which is a byproduct of rice, one of the Philippines’ leading agricultural crops. Recent literature indicates that RHA bricks can deliver favorable thermal performance due to their relatively lower thermal conductivity without compromising the mechanical and structural properties necessary for wall construction.
The comparative assessment of these materials will be conducted using the Passive House Planning Package (PHPP). While PHPP is primarily used in Passive House certification projects, it also serves as a reliable tool for evaluating a building’s thermal performance and energy demands based on the specifications of its envelope and systems. In offering insights into the potential of RHA bricks as an effective walling material, this study presents a thermally efficient solution for Philippine residential design while promoting the use of its local resources.