Living walls and their effect on indoor environmental quality and occupant satisfaction in the workplace

Occupant health and comfort has suffered as a result of tightly sealed buildings and construction that divides humans from nature (Wolverton, Douglas, & Bounds, 1989). Biophilic design is a way of reconnecting occupants with nature. Integrating nature with the built environment is crucial to improve the occupants’ experience in a building. Applying plants to walls is a way to directly incorporate nature in an interior environment. Living walls have emerged as not only an aesthetic biophilic design solution, but a true representation of the benefits nature being utilized in the built environment. These planting systems enhance indoor environmental quality by way of natural processes of air filtration, acoustic attenuation, and even thermal control (Gunawardena & Steemers, 2019). A visual connection to nature also offers occupants mental restoration through fascination, or a gentle distraction that requires no effort or directed attention (R. Kaplan & Kaplan, 1989). The purpose of this study is to investigate the impact living walls have on indoor environmental quality and occupant satisfaction. After reviewing the literature surrounding the benefits of living walls, it can be hypothesized that living walls can improve indoor air quality, thermal comfort, acoustics, and even positively affect the lighting design in a space. A multiple case study approach was used to evaluate how living walls affect occupant satisfaction and indoor environmental quality. The following five commercial buildings were investigated: Nixon Peabody District of Columbia, OFS Corporate Headquarters, Toyota Motor North America, Etsy Headquarters, and Delos Headquarters. Each site houses a large-scale living wall system and is certified under either the Leadership in Energy and Environmental Design (LEED), Living Building Challenge (LBC), or the WELL Building standards. The different strategies for data collection include online research, observational analysis and field measurements in each area of indoor environmental quality, and finally an occupant survey. Due to the current state of the workforce and fall out from the COVID-19 pandemic, the last two research strategies were not able to be completed and the online research and observational analysis was completed remotely. Due to the lack of deciding evidence and the need for verification, this data is intended to be used as a preliminary analysis of each site. Based on the information gathered, it can be expected that living walls are most effective when used in a common area in an office, and the plant composition has a lot to do with the success of the living wall. The living walls studied are expected to have the strongest impact on thermal comfort and the occupants’ access to natural daylight. The Delos headquarters’ living wall systems were the overall most effective because of the built-in mechanics making it an active air purifier and the number of them located around the office. Field measurements and an occupant survey are still needed to fully understand how living walls impact occupant satisfaction. The proposal for future study is developed to build on the foundation presented in this study and to ultimately produce results that could be a tool for evidence-based design in practice