This paper presents the results of a questionnaire survey on the use of air conditioners in houses in Surabaya, Indonesia, and Kuala Lumpur, Malaysia. The objective of the survey was to clarify what temperature and humidity levels people in these regions prefer in order to feel comfortable, with special focus on their sleeping environment. This was determined through survey responses and by measuring the thermal environments in their bedrooms. The questionnaire file was distributed to 64 university students in Surabaya and 65 in Kuala Lumpur. The students interviewed their family members and described their own experiences in their daily lives at home. The survey results show that the respondents set their air conditioners at very low temperatures. They also show that more than half of the respondents reported a cold or cool thermal sensation while using the air conditioner. Many respondents also reported various health problems and feeling cold while they were sleeping.

Energy consumption for air conditioning systems (air conditioning system) increased along with the increasing need for fresh air and comfortable in the room especially apartments. FAC system (Floor Air Conditioning) is growing because it is more energy efficient than CAC (Ceiling Air Conditioning) system. However, the position of the AC supply is on the lower level at the FAC system causes draft discomfort becomes greater as air supply closer to the occupants so that thermal comfort can be reduced. Heat mixture of windows, exterior walls, kitchen, and occupants in the studio apartment affect thermal comfort in the room too.This study aims to determine the position of the AC supply which has the best thermal comfort of FAC system in the studio apartment. It can be done by analyzing ADPI (Air Diffusion Performance Index), the distribution of air temperature, wind speed, RH (Relative Humidity), and DR (Draft Risk) to change the position of the AC supply supported by CFD (Computational Fluid Dynamics) simulation.This result prove that AC position 2 (on wall near the kitchen) is more comfortable than AC position 1 (on the bathroom wall) because AC position 2 away from occupied areas, thereby reducing the occurrence of draught discomfort.

This paper proposes strategies for reducing energy consumption for cooling in residences in hot and humid climates. Based on the results of fieldwork measurements and questionnaire surveys, a simulation of indoor thermal environments in consideration of air conditioner operation was carried out, in order to evaluate energy consumption by air conditioners. This simulation program takes into account both heat and moisture transfer in building materials. In order to simplify the calculation and due to lack of measurement of ventilation volumes, the ventilation volumes are assumed as constant values depending on open or closed windows. The combined effects of building air-tightness and the opening time of windows for ventilation were examined. Making an entire building airtight results in a small reduction in energy consumption, as the air-conditioned area increases. Meanwhile, simply making an air-conditioned room airtight is more effective for reducing cooling energy consumption. Irrespective of this, nighttime ventilation of non-air-conditioned spaces is quite effective in reducing sensible cooling load. Thus, introduction of not only a high degree of insulation but also air-tightness along with well controlled ventilation is required to achieve energy savings in hot and humid climates.

A deep-plan office building design limits daylight access on the workspace distant from the side window. Horizontal Light Pipe (HLP) is one of the light transport systems that can deliver daylight to these areas. The research aim was to explain and evaluate the effect of HLP’s opening distribution area on daylight performance at deep plan-private office space. The research method was experimental with simulation as a tool. Daylight level and distribution of the base case, HLP with an opening distribution area of 6.6 m2 were compared with the case, HLP with an opening distribution area of 3.41 m2. The results showed that both cases distributed daylight uniformly. A 50% reduction of HLP’s opening distribution area, from 6.6 m2 to 3.41 m2 improved the average Daylight Factor as big as 6.42%. HLP with a smaller opening distribution area can be applied as the main source of daylight on deep-plan office spaces

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Window-opening is one of the most important adaptive behaviours affecting indoor thermal comfort as well as household energy consumption in the tropics. In this study, large-scale surveys were conducted in major cities of Malaysia and Indonesia to extract various typical daily patterns of window-opening, air conditioning (AC) usage and fan usage among occupants in the tropics through a data mining approach based on a cluster analysis. Furthermore, influential factors for window-opening patterns, focusing especially on contextual factors and household attributes, were determined through a logistic regression analysis. As a result, several typical daily patterns of window-opening, AC usage and fan usage were extracted, respectively, even under the same hot-humid climate. It was found that household size, age of respondent, household income and concerns about insects were the most influential factors for daily window-opening patterns. The results of this study will fill the existing knowledge gap in driving factors of occupant behaviour in the tropics in which few studies have been conducted.

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In conventional air conditioning design, the comfortable range of temperatures is 25 to 27°C, with relative humidity levels of 40 to 60%; these numbers vary only slightly based on a person's race and country. Several studies in tropical climates show that the observed thermal comfort requirement often does not agree with those obtained based on experiments mainly using North American subjects. However, there is no consistent rationale that explains why the comfort requirements are different in a hot climate, suggesting more surveys on thermal comfort may be needed in the tropics.In Asia, there has recently been a rapid and widespread diffusion of air conditioners. Therefore, we conducted a survey to clarify what temperature and humidity level people in Asian countries prefer in order to feel comfortable. Following that research, this article presents the results of a questionnaire survey on the use of air conditioners in houses in hot, dry climates.Nizwa and Rustak, Oman, which are characterized by the hot, arid climate of the Arabian Peninsula, were chosen as survey areas. The questionnaire survey was distributed to students of Nizwa University. Questions were asked about the duration of air conditioner use and the preferred air conditioner temperature setting. In order to determine how respondents felt about their indoor environment, we also asked about the thermal sensations that were experienced while using the air conditioner. In both cities, the mean operating time of the air conditioner was very long. The respondents reported selecting a low temperature setting while sleeping despite the fact that many of them reported that they were cold while sleeping. Ninety percent of respondents reported a cold, cool, or neutral thermal sensation while using the air conditioner, without feeling discomfort.