Image source: Rocky Mountain Institute
Well, this is a useful guide but not 100% of the suggestion can be used in tropical countries with high humidity, high heat and full year round of sunshine. Improvements like skylights, light tubes, low-E coating, PV and solar thermal (which is not being mentioned) are extremely useful in greatly reducing the electricity bill. Why? Cooling (refrigeration and air conditioning) is the major cost (>55%) in more than 90% of the households in Malaysia. So which is your favourite option?