I'm not sure about electricity cost in the Philippines, but here in Hawaii we have the most expensive in the US, and most of the people I know deal with the climate in more traditional tropical ways. The percentage of people using AC is higher near the water, but it gets much less muggy rather quickly with elevation gain, making air conditioning less critical or even unnecessary for pleasant living conditions.. I"m at 1300 ft., which has fantastic temperatures year round, but we certainly get a lot of rain that does encourage mold. The thing I've found most critical is to maintain good airflow. Enclosed spaces are mold and mildew's friends, unless they are water vapor tight.