Solar access refers to the ability of a living unit to continue to receive sunlight without obstruction from any other properties or structures. The provision of appropriate solar access is considered to be important to residents' health, comfort and daily living. Guidelines and standards for the provision of sunlight have been formulated in the past few decades in low-density living environment. In subtropical high-density living environment like Hong Kong, associated guidelines and standards are generally lacking and it has become a growing concern for better provision of sunlight to residential units. It is also important to consider residents' preference of solar access in the formulation of standard for solar access and daylighting, as well as urban planning and building design. The present paper presents the results of a questionnaire survey regarding residents' preference of solar access in terms of time, amount, place, and purpose of the exploitation of sunlight, as well as an exploratory factor analysis (EFA) which examines the influence of environmental parameters on residents' preference. Results show that the majority of the respondents (72.0%) were satisfied with the current situation of solar access in their households. Only 12.4% of the respondents felt unsatisfactory about solar access of their flats. Over half of the respondents preferred to have sunlight penetration into their households in the morning. There is likely a need to improve the provision of solar access in terms of the time of sunlight received by residents since only about 40% of the respondents had the same time of sunlight entering their flats as they expected. There are not any particular preferences of the expected amount of solar access. Sufficient solar access was found to be more important than view outside respondents' flats with an overwhelming 70.2% of the respondents in favor of sufficient solar access. The EFA results indicate that observed microclimatic parameters were the dominant influencing factors and closely followed by visual elements of residents' subjective feelings about their flats. It implies that the incorporation of microclimatic environments into current design standard and guidelines should be considered. Further studies can also be conducted to examine the behavior of residents, i.e. activities occurred in the units, in more details. Current findings provide a basis of the preference of residents to solar access of residential flats in high-density tropical cities using Hong Kong as a case study. Policy-makers, as well as planners and architects, should therefore take the findings into account when establishing appropriate guidelines and standards, especially for high-density subtropical cities, in order to provide residential units with better sunlight environment. (C) 2011 Elsevier Ltd. All rights reserved.