This is a Canadian study which observes a high-rise multi-unit residential building (with a LEED silver rating) in summer and investigates the how residential users interact with their blinds (white roller blinds) in terms of time schedules for opening and closing blinds, differences percentage of closure and frequency of blind movements.
- ‘Blinds in homes are operated significantly differently than commercial buildings because of the increased need for privacy and the vastly different occupancy schedules.’
- ‘…blinds can be effective for mitigating overheating and reducing peak cooling loads.’
- ‘In addition to blind movement, the type of blind an occupant chooses has been shown to significantly affect interior cooling loads. A further energy reduction of 13% can be achieved by switching shading devices from typical blinds to interior reflective screens.’
The observational field study observed 370 windows including windows on the south-east, south-west and north-west facades. Photographs were taken of each facade every two hours between 7am and 7pm for six days, on weekdays and weekends, with varying weather conditions. Shade position, window openings and percentage of closure (blind occlusion) were recorded. Four sunny weekdays worth of data was used and compared against a mostly sunny weekend and a cloudy weekday.
Within the four sunny weekdays blind occlusion was reduced on the north-west facade in comparison to SE and SW, agreeing with other studies that northerly facades tend to be less occluded. Office studies have concluded northerly orientations and blind occlusions are determined primarily by privacy, view and glare.
Blind closures occurred 33% more on the ground floor of the south-east facade than blind closures on the second floor, proving privacy is a major motivator for instigating blind movement. In addition, the south facade’s blind closures increased as the floor level increased. This is potentially to do with the less shading being provided from neighboring buildings.
The majority of blind openings (48.6%) occurred between 7am and 9pm. Blind closure patterns were less clear to identify 27% of blinds were closed between 5pm and 7pm, potentially due to evening privacy or closures occurring as soon as occupants return home from work.
To analyse frequency of movements the windows were grouped into condominiums, which there were 102 in total. Of these households, 25 never moved their blinds (potentially because they were vacant) with 62.4% not moving their shades during the period of a day. This further proves that building occupants infrequently move their shades and is consistent with the findings from office studies.
Read the report here.