What is a Shadow Study?
The shadow analysis allows a designer to study the amount of solar access to different parts of the site and building design. In new construction or renovation, it is important to assess the impact of physical obstructions and their affect on the access to direct solar radiation in not just the current conditions but also the future. Many zoning requirements include having a shadow study to show how a new building has an impact on the existing conditions. Here are 5 ways designers can use shadow analysis to inform design decisions:
1. Impact on Massing and Orientation
Based on the shadow studies, impact from neighboring buildings, trees and more can help determine the massing and orientation of the proposed design. This can be don e to either take advantage of the sun and views, or limit it based on the project location and site.
2. Self Shading and Glazing Location
The shadow analysis can allow designers to understand the times of day/year when the proposed design self-shades itself. For cooling dominated climates this can allow the designer to add fenestration in “shaded” parts of the façade to reduce solar heat gain, while for heating dominated climates, this allows designers to do the inverse and place fenestration for high heat gain. Many engineers have been able to showcase the ability to reduce peak cooling by 5%-15% by appropriately taking advantage of the shade vs exposed façade design.
3. Impact on Outdoor Patio, Swimming Pool locations
Maintaining outdoor comfort using passive strategies like shading (or lack of shading, depending on the weather) is essential. Designers use shadow studies to determine the location of outdoor patios and swimming pool locations. For instance in a hot and humid climate like Atlanta, shadow studies allow designers to place outdoor spaces in shade for use during the summer months.
Above is a sample of shadow study images from cove.tool compiled together to represent the effective annual shade cast during each season. A study image is taken at every hour during occupiable hours (8am to 7pm).
4. Impact on Urban Context
Providing consistent access to sunlight is essential to maintaining access to sun and healthy trees in urban green spaces. With increasing urbanization, a tall building placed between an existing treed area and the sun has the potential to have a deleterious effect on the street level and existing trees, both on their long-term health and the concomitant value they have in mitigating an otherwise harsh urban environment.
5. Impact on Landscaping Plant Selection
Various plant species have different solar requirements and minimum hours of direct sun requirements. The ability to study shadows allows designers to understand hours of direct sun on various parts of the site which can be critical for plant selection.