Daylighting Strategies
Fougeron’s portfolio illustrates the various strategies she uses to bring natural light deep into a home’s inner spaces. In addition to the large, strategically placed window walls and open interiors she favors, many of her home designs include snug interior courtyards open to the sky, skylight-covered light wells, and cantilevered facades that seem to reach out toward the daylight in close-in urban spaces. Skylights and high windows are also used in rooms with limited wall space, or those that especially benefit from natural light and ventilation, such as kitchens and baths.
While there can be tradeoffs in energy costs when it comes to maximizing the amount of glazing in a design, Fougeron notes there are also work-arounds that can help restore the balance. For example, high-performance glazing products may be more expensive initially, but if they reduce the home’s energy loss or load, the extra cost is repaid over time. “Natural lighting is more environmental, and it can be economical,” she says. “You really want to talk about the life-span of the home.”
Still, because windows and other glazed openings generally offer less of an insulating barrier than structural walls and roofs, they can negatively affect a building’s overall energy rating—a major consideration in areas that experience extremes of heat and cold. For this reason, careful placement, attention to product specifications, and smart product choices are critical, especially during a home’s initial design phase. Windows and other glazed building materials also must be certified by the National Fenestration Rating Council to meet federal and state energy code requirements. As these requirements have become more stringent, manufacturers have developed and improved their products with innovations such as radiant heat–blocking films, multiple-pane sashes with gas-filled insulating spaces, and thermally efficient construction techniques.
As a result, today’s fenestration products are more energy efficient, allowing architects and builders increased latitude as to placement and the total amount of glazed areas permitted in homes under the energy code rules, which can lead to increased daylighting.
Peter Anderson, of Anderson Anderson Architecture in San Francisco, says that builders and designers need to ask themselves whether it’s more important to “limit the glass area or find an environmentally appropriate way to provide what you want. There are ways to offset energy use. We feel people should take a more holistic view of energy consumption.”
To maximize the distribution of daylight in a structure while reducing its energy liabilities, Anderson recommends the use of solar modeling software, such as Ecotect Analysis from Autodesk, in conjunction with Google Earth and Google Maps. These readily available tools have greatly simplified determining optimum building orientation, heat-gain and heat-loss parameters, and sun paths throughout the structure, he says, which helps to eliminate problems early in the design process. “We do daylighting studies for all of our projects,” he adds.