Taking Daylight to the Next Level: How Daylighting Analysis is Changing Design

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Taking Daylight to the Next Level: How Daylighting Analysis is Changing Design

10 DESIGN’s Ashjar at Al Barari residential project. Image Courtesy of 10 DESIGN

 

Daylight analysis used to be a cumbersome process, requiring new 3D models, extensive inputs, and significant technical expertise. But new tools are far faster, more intuitive, and integrated into the designer’s modeling environment—making this analysis accessible to every designer, and for every type of decision. This is happening at the same time that new metrics are being developed to evaluate daylight; therefore our ways of measuring are changing at the same time as they’re becoming dramatically more accessible.

If current practice is shaped in part by the advantages and limitations of rendering tools, what will be the effect of these new tools and metrics? What possibilities do they open up—What new ways of conceptualizing design? There are different types of daylight metrics, which allow architects to understand daylighting in different ways, and are therefore useful for answering different types of design questions. I’ll consider three types here: whole-building annualized metrics, annualized daylight visualizations, and time-of-day visualizations.

10 DESIGN’s Ashjar at Al Barari residential project. Image Courtesy of 10 DESIGN

Annualized Metrics & Objective Comparisons

Annual daylight metrics summarize the daylight performance of a building throughout an entire year, taking into account design, location, and weather. These metrics help to answer the question: “Where does my design stand, relative to best practice, to specific daylight targets, or to another design?” Terms like Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE) are simply summaries of how frequently the space gets adequate daylight (sDA) or whether there’s risk of too much light (ASE).

The results are more powerful than you might expect. A recent example is Ashjar at Al Barari, a residential complex designed by 10 DESIGN, in which the design team used annual metrics to understand the daylighting potential and glare risk of overall building form, glazing ratios, and shading strategies. “Each residential type features a unique and variable aesthetic,” says Sean Quinn, Head of Sustainable Design. “The goal was a responsive design approach not a repetitive solution.” Shading in particular became a key element of the design’s aesthetic. These annual daylight metrics were used alongside annual energy metrics in order to draw out the tradeoffs and synergies between the two results. In this way, these metrics open the possibility of actually designing daylight—of crafting strategies that shape daylight, just as an architect shapes program relationships, views, or formal composition.

Conceptual energy and daylight analysis. Image Courtesy of 10 DESIGN

Annualized Visualizations & Decision-Making

The weakness of annual metrics is that they don’t help architects understand why a design is performing in a certain way. The high-level numbers are opaque: where are the dark spots and where are the bright spots? This information is critical in shaping daylight in an intentional way. This is where annualized daylighting visualizations come in: they show how the daylight is spatially distributed throughout the year, allowing detailed investigation into the lighting levels of each space. These images help answer the questions: “Am I comfortable with these light levels and patterns? Where are the problem areas? How can I improve the design?”

Sterner Design’s Iowa residence. Image Courtesy of Sterner Design

An example is a residential project in Iowa designed by my own firm, Sterner Design. A partially underground house with an aggressive energy target, it was critical to use glazing carefully, for both passive solar heating and to get quality daylight into the space. Early on I used daylighting visualizations to compare options and understand the depth of daylight penetration given the different floorplans. Later analysis focused on the quality of daylight in the main living areas, where good daylight is most important, and allowed me to quickly test strategies for improvement, such as taller windows, strategically placed skylights, or strategies for “borrowing” light from the well-lit upper story. The analysis allowed me to tune the building form, space layout, and glazing according to the sun in a way that simply would not have been possible before.

Annual daylighting visualization. Image Courtesy of Sterner Design

Time-of-Day Visualizations & Communication

While annual metrics and visualizations are effective diagnostic and design tools, they don’t always provide the most intuitive understanding of lighting conditions. What does the space feel like? How does the experience change over time? What is the light like in the middle of winter or the height of summer?

These are questions for which time-of-day visualizations are well-suited. Whereas the other metrics speak to macro-level comparisons—attainment of goals, annual averages—these speak to the experience of the space, yet quantify that experience in a way that renderings cannot.

This was what led Allan Joyce Architects to use a combination of interior renderings and point-in-time analyses to design a Tearoom retrofit in Harrowgate, UK. The client wanted to understand whether the design “worked”—what the space would actually feel like given the proposed changes. The architects paired renderings and time-of-day visuals to communicate the experience in a way that was both intuitive and verifiable. “Our client was delighted,” said Toby Evison, Architect at Allan Joyce. “They could easily comprehend the effect of the design proposals, and this directly informed their decision making.”

Renderings and time-of-day visualizations. Image Courtesy of Allan Joyce Architects

As these new possibilities reach more designers—the ability to shape daylight, to interrogate it objectively, to define targets and evaluate outcomes—it becomes possible to shape a building according to daylight. This enables architects to work on the poetic and the pragmatic simultaneously: to understand with equal ease the aesthetic and pragmatic implications of design decisions. By rendering visible daylighting data, architects can interact with it, form it, mold it to purpose, and ultimately achieve better designs—designs that both work and inspire.

Carl S. Sterner, Assoc. AIA, LEED AP, is the Owner of Sterner Design and Senior Product Marketing Manager at Sefaira, a software company specializing in performance-based design. Visit Sefaira at the AIA Convention in Atlanta at booth 2874.