Building smarter for a finite planet

06/07/2014 12:00 AM

06/07/2014 7:44 PM

Watch most any documentary about pollution or environmental issues and you’ll see plenty of footage about the usual culprits — factory or power plant smokestacks spewing noxious plumes into the air, highways clogged with cars, overflowing landfills.

What you likely won’t see is your own neighborhood, even though your home and others on your street share some of the responsibility for the shape our planet is in. In fact, consensus estimates on conventional modern homes place 20 percent of global carbon emissions and 15 percent of global energy usage at our collective doorsteps.

The upside to such sobering statistics is that there’s a lot of room for improvement, and Spanish journalist Lorena Farras Perez’s Eco Design Outside offers a nice overview of options to make that happen. At their core, all of these ideas and options center on sustainability — using resources and energy (fuels) at a rate that allows their replacement, and in a way that might help tame our growing climate instability.

There’s not a lot of new ground here, but having so many ideas compiled in one accessible guidebook might go a long way toward enlisting change in the daily habits of average homeowners. Also, Perez is good at serving up small suggestions that have a bigger impact than you’d expect.

For example, for natural pest control in a garden she recommends spraying extract from crushed dandelions or boiled artichoke leaves; this is a simple, nontoxic solution to insect pests, and it also has the virtue of avoiding the multiple problems associated directly or indirectly with synthetic pesticides and herbicides — their toxic residue in soils and water supplies, the energy and petroleum resources used to manufacture them, and the pollution associated with their transportation.

The book offers other alternatives to conventional home habits, such as green roofs planted with sedum and other succulents, or “natural” swimming pools that use a connected pool with aquatic plants to keep the water clean and healthy.

But the biggest impact could stem from a design/build approach Perez refers to as “bioclimatic housing,” which involves a host of decisions that together can make a home much more environmentally friendly. It’s all about coordinating design details and materials choices with what nature is dishing out at the site. Here’s a breakdown of some of the key issues:

•  Site orientation: In our North American climate, a home that “opens” to the south via large expanses of glass can better capture the benefits of winter sun to reduce energy consumption for lighting and heating. A similar principle applies to east-facing windows, but a lot of glass exposure on north and west walls will likely result in excessive heat loss or gain, respectively.

Conversely, a mostly solid, heavily insulated north wall provides a buffer against cold winter winds that can strip heat from a house.

•  Thermal mass: This is related to issue No. 1, because mitigating the temperature swings caused by solar energy helps reduce energy usage. Stone, masonry, soil and water all have excellent thermal storage capacity, which means they can soak up the sun, absorb its heat energy, then slowly release it as ambient temperatures cool. Pairing south-facing glass with a Trombe wall (basically, a massive interior heat sink where that infrared energy can park and then re-emerge later) helps reduce temperature fluctuations.
•  Managing airflow: Adequate ventilation serves another key function in making a house livable, and harnessing air’s natural convection movement (warm air rises, cooler air descends) can mean reducing or eliminating the need for mechanical systems to keep an interior comfortable.

Some passive features, such as wind catchers (a vented tower connected to the living space below), create a venturi effect that produces a slight vacuum inside the house so outside air gets pulled in; this happens without electric fans or other powered systems.

•  Managing daylight: Windows, skylights and solar tubes combine to distribute natural daylight throughout a home, even in spaces with no exterior walls. Some regions have a different problem — too much sunlight, generating heat — so canopies, wide roof overhangs and deep porches are useful features in these circumstances.

Other chapters in the book explore more specific topics such as energy systems and resources, and what constitutes a “green” building material. Many ideas can be applied to existing homes, others are practical only for new construction, but the book’s approach is comprehensive enough to let readers assess which solutions might work best for them.

Aside from an occasional lapse in logic (propane patio heaters are nixed in favor of “non-polluting” electric versions, but that electricity just might come from a coal-fired power plant), the book is a nice blueprint for recognizing and creating homes that are kinder to our planet and a better investment in our collective future.

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