Hawaiian architect Virginia Macdonald, FAIA, who is 88 years young, has written Heating or Cooling Your Building Naturally, Solar Architectural Solutions, to serve as her legacy and ode the principles of working with nature to design comfortable housing. Through an initial explanation of her principles and 10 case studies, the author relates how vertical ventilation and controlled daylighting—to the exclusion of air-conditioning and daytime electric lighting—can be applied to “the buildings where we spend our lives and that, in turn, affect our climate and the very air we breathe.”

The premise is simple and has been used throughout the ages in all cultures and climates, Macdonald points out. “Hot air rises. That’s the starting point for all the ideas and designs contained in this book. By taking advantage of the natural vertical flow of air, it is possible to regulate the temperature of any enclosed space, making it cool or warm as needed. With nothing more than good natural design, a home, office, or business space can be kept comfortable without the use of expensive air conditioning.”

Macdonald says an architect only needs three things: in-vents, located on a low place on the wall, or in the floor, to control the amount of cool air coming into a structure; out-vents, located near the roof or around the skylights to let warm air out, and a heat source. She advises the use of “spectrally selective” skylights to regulate light and heat to create the “10-degree temperature differential needed to accelerate air movement.”

“For effective passive-solar ventilation, the building should act as a thermal chimney, always allowing warm air to move up and out … The benefits of these form-follows-function designs include documented savings in electricity, lighting, security, and window expense. They also control the amount of cool replacement air flowing into a building, reducing dust, moisture, and ocean salt,” key ingredients of stemming mold and mildew in warm, humid areas.

Fixed windows, venting skylights
“All of the buildings featured in the case studies are designed so that they bring controlled natural light into the building,” Macdonald writes. The author says her clients readily accepted controlled daylighting as a feature of the projects described in the case studies, but not all project owners “agreed with the author’s use of closed (fixed) windows to assist the vertical ventilation, and therefore some operable windows are combined with the fixed windows.”

Still, in preparing the case studies for the 131-page publication, Macdonald confirms that “fixed windows are in fact an essential component for effective vertical ventilation.” She explains that operable windows create opportunities for cross ventilation, which reduce the efficacy of the thermal chimney effect. As an example she says that if she releases a balloon in a room where all the ceilings and closets have been removed, the balloon would rise unhindered. But once a window is opened, the balloon gets confused, blown crossways and sideways. “One has to choose between vertical or horizontal ventilation,” she says.

“Venting skylights are the most efficient way to achieve temperature differential and incorporate out-vents for proper vertical airflow,” Macdonald says. “Sunlight that enters through skylights warms the air creating the dt, while the vents allow this warmed air to exit.” Different glazings help regulate the amount of light that enters the space. Vents can be hidden and protected from outside weather factors, like rain or snow. The design also has the added security benefit of hindering would-be intruders. She advises architects to consider the orientation of roof planes to ensure design plans take best advantage of the sun.

Case studies

• Macapple Office/Residence showcases Macdonald’s principles of design. Its 42 fixed in-plane skylights and many fixed-glass windows control airflow, noise, dust, and security. She also features many other “sustainable” design tools.
• Dr. Lee-Ching Office won over neighbors because its design picks up the character of its historic district. The doctor realizes a cost savings, Macdonald reports an 80 percent electric-bill savings through the use of natural lighting and vertical ventilation.
• The Fordham Bathroom, of which, Macdonald notes, “it may be part of the state code to encourage open windows, but the truth is that cross-ventilation often creates more problems than it solves.” The architect installed a fine mesh in the floor vents to let in cool air and keep out cinders. A skylight on the roof allows out-venting.
• National Park Service Firehouse demonstrates how vertical ventilation can work in a small independent space for firefighters. The Volcano Fire House skylights brighten a work space and keep morale up in what is typically a rainy, gray, and gloomy environment.
• Dr. & Mrs. Ung Lee Home proves that the principles of cool, natural vertical ventilation do not have to be limited to the smaller, local-style homes. Here Macdonald uses out-vents set directly into the ceiling carefully concealed behind ceiling moldings, concealed kitchen skylights, and flat sloping skylights in the entry area, and in other inconspicuous places in the home.

Singing the same tune
For more than 30 years, Macdonald (who didn’t get her architecture license until she was 60) has used the principles of vertical ventilation in a broad portfolio that includes bathroom remodels, offices, hospitality projects, and home construction. She says it puzzles her why more architects do not design to use the sun. “It’s free and it’s there.” She says that while she practiced in Hawaii, passive solar design is applicable across the nation.

Macdonald notes there are many benefits to passive solar design.

• Save up to 80 percent on electricity without the need for air-conditioning, dehumidifiers, or artificial lights until after dark.
• Save up to 40 percent on construction costs with fixed glass windows.
• Promote healthful living with buildings with air ventilation that encourages mold- and mildew-free interiors and natural lighting to reduce eye strain and help develop stronger bones, reduce energy consumption for a better world, and increase safety with better security and greater fire containment.

“I’ve been singing the same tune for 30 years,” says Macdonald, an award-winning architect who says she has received only one honor for her passive solar work. She is hopeful that this book lays out for architects and the public the design tools she’s been advocating for three decades. “Follow the guidelines in the book and help the planet. If enough people do this, we can transform the United States from being a major source of environmental problems to a place where a healthful environment is treasured and respected, thereby setting a good example for the world.”

—Tracy Ostroff

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