Following the retrofit, the newly re-opened skylight provided a significant change in the daytime lighting conditions in the study area of the store. Shown below in Figure 18, the addition of the skylight provides a distinct visual contrast to the surrounding area. As outlined in section 6.2, the intervention involved re-opening two of the four sides of the skylight (keeping the east- and west-facing sides of the skylight covered to block the low-angle early morning and late afternoon sun), as well as adding supplemental diffusing material to prevent glare. In addition, indirect-direct linear fluorescent lighting was added at the perimeter of the skylight to illuminate the interior of the skylight well and provide general illumination at night when no daylight is available, and additional halogen accent lighting was installed to highlight merchandise displays. Figure : Intervention Area – With Skylight Opened Figure : View of Re-Opened Skylight, Showing East- and West-Facing Sides Covered, as Well as Fabric Scrim and Electric Lighting in the Skylight Well The re-opened skylight resulted in significant changes in the physical lighting conditions in the space. Before the intervention, the average illuminance level on the sales floor was 30 As shown below, in , average illuminance levels under, and surrounding the skylight ranged from 55 to 64 foot-candles over the course of the day, during an October 23, 2009 site visit. Values directly under the skylight were as high as 120 foot-candles in some locations. More significantly, the results as seen in Figure 20 show that the daylighting design of the skylight retrofit had succeded in providing high-quality illumination without creating significant contrast between the area directly underneath the skylight versus other parts of the store. The ratio of maximum illumination under the skylight to average of illumination surrounding the skylit area ranges from 1:1.3 to 1:1.75 while the ratio of the illlumination under the skylight to the lowest illumination level surrounding the skylight was between 1:2 to 1:3. Thus the design features installed in the skylight (see Figure 19) succedded in minimizing chances of glare under the skylight as well as minimizing contrast ratios between the skylit area and the surrounding areas while making a visual impact on that area of the store. Note that the illumination measurements both under the skylights and the surrounding areas are a combination of daylight and electric lighting.
can make it hard to read displays or evaluate quality. Easy to Read Merchandise Display (0.02)  Easy to Read Overhead Signage 0.27 Easy to Gauge Merchandise Quality (0.02)  Easy to Gauge Merchandise Color 0.10 Easy to Read Merchandise Tags/Labels (0.23)  Customers are finding it hard to read merchandise tags or find way around the store and the study area. However, this seems to be pervasive in the store and not to the study area in particular. Ease of Wayfinding in this Dept (0.11)  Ease of Wayfinding in this Store (0.31)  Helpfulness of Sales Associates in this Area 0.03  Customers are generally happy with the quality of service from the sales associates Helpfulness of Sales Associates in this Dept 0.07  Helpfulness of Sales Associates in this Store 0.06  As seen in Table 3 , the customers have a generally positive feedback to the daylighting retrofit. Overall customers rate the attractiveness of the department and the clothes slightly higher than in the pre-retrofit case. Customers seem to find wayfinding in the store to be more difficult. Because of the structure of the survey questions, positive trends do not always indicate positive responses to the skylight. For example, for the first two questions, indicating the amount of time since the customer was last in the department or the store; positive trends indicate less frequent visits. While positive trends on these two questions indicate that shoppers are visiting the store slightly less often than those surveyed prior to the intervention, it is notable that the positive trend in the “time since last in the department” question is less than the trend for the store as a whole. In other words, even though the average frequency of overall store visits has decreased, frequency of visits to the study area department has not decreased as much. Survey responses indicate positive trends in “attractiveness” of the store and merchandise as a result of the skylight, but trends were mixed for performance of visual tasks. Responses indicate that the daylight improves the ability to assess merchandise color and to read overhead signage, but had no effect on the respondents’ ability to read merchandise display information or to gauge merchandise quality. Respondents’ ability to read merchandise tags and labels declined in the post-intervention scenario, although this seems to be happening at the store-wide level and not limited to the study area.
Customers’ increased perception of attractiveness is an indication that the skylight has improved the visual environment in the but the problems with visual tasks and wayfinding remain a point of concern. It is also possible that sources of glare caused by electric lighting could be responsible for visual task problems, but a cause-effect cannot be determined based on the data. Assessing changes in customer experience in the post-intervention condition was further complicated by the fact that initial survey responses in the pre-intervention condition were already positive, leaving little room for improvement. E.6.2 Associate Survey Results Table : Sales Associate Survey Analysis Results Survey Question Delta Ratio (post-pre) Overall of Responses Interpretation of Time Shoppers Spent In This Area of the Store 0.2 Customers are spending more time in the study area and trying on more clothing indicating a positive visual impact of the daylighting Time Shoppers Spent Talking with Associates 0.3 Time Shoppers Spent Trying on Clothes 0.6 Change in Number of Transactions in Dept 0.9 Number of transactions have increased and product returns have reduced Change in Number of Product Returns (0.3)  Change in Number of Return Shoppers 1.1  The study area is getting more number of new and returning customers Change in Number of New Shoppers 1.5  Dept is Visually Attractive to Associates 0.5 Sales associates are happy with the overall lighting conditions and think that ht daylighting adds to the merchandise visual appeal Lighting Conditions are Comfortable 0.1  Lighting in Dept makes Merchandise Appealing 0.6  of Dept are too Dark (0.2)  Parts of Dept are too Bright 1.9 