The coastal area of Northern part of Jakarta is the densest coastal area in the region. Based on Indonesian statistical bureau, It has occupied by 12.100 inhabitants per KM², the political regime avoiding a reclamation policy in its development has put the citizen in problems such as high land price to limited land purchasing ability, so the government has put housing policy to affordable multi-story rented public housing.  The citizen who lived in public house faced an uncomfortable thermal comfort condition with area mean temperature reached 28,7◦C and 75% of relative humidity, far from comfort standard 25,5◦C and 60% of relative humidity.

This research aims to examine optimization factors to indoor thermal comfort, which took part in a public house located in the northern part of Jakarta. To reach a better thermal comfort, the inhabitant installed an Air Conditioner (AC) unit in some units independently to fit into a standard housing unit. The default electric capacity is 1.300 Watt, and after an electricity use analysis breakdown, the maximum capacity of AC can be installed is only a ½ PK split model 340 Watt and 5.000 btu/h. This model is not compatible to its unit architecture (no balcony and no outdoor containment unit) and also not fit to 36m2 minimum standard so it will push the AC to the maximum level and not efficient in energy usage, so an architectural intervention needed to provide the better policy.

This research also analyzed the 136 respondents of inhabitant’s thermal comfort perception in each residential unit, the result shows 73% occupants who lived in a non-AC unit dissatisfied to its thermal comfort and 82% occupants satisfied to its thermal comfort but dissatisfied to its electricity performance leads to inefficient energy use.