Remodeling for passive cooling - landscape architecture

Remodeling for passive cooling Passive cooling is usually planned into the earliest stages of a house's design. It's not often accomplished by remodeling. But architect Sandy Baum and his wife, Linda, took on that challenge when they bought a 30-year-old ranch house in Palm Desert, California.

To cool the house with minimal energy consumption, they used a combination of tactics: planting outside to provide shde inside, creating trellised buffer zones, adding new spaces to boost air circulation (and improve traffic flow), and fine-tuning heating and cooling systems.

Today, summer temperatures indoors are consistently 10[degrees] to 15[degrees] cooler than those outside. Mature trees spread a leafy umbrella overhead. And glass-walled additions open the house to a flow of cool air from shaded decks on two exposures.

Landscaping to beat the heat

First, the Baums planted hardy desert trees to fill gaps among the 16 trees already growing on the arid site. By berming the property's perimeter, they also created a low area around the house--a basin to collect cool air.

Two years later, when the desert trees had become established, the Baums introduced some shade lovers. A few years after that, they ventured some exotic species such as plumeria, tree ferns, ginger lilies; a 6-foot wall around the compound keeps these from freezing in winter.

In just 5 years, the rich, forest-like garden has created its own microclimate, cooling soil and slowing evaporation. Irrigated by a drip system, it requires less water than neighboring lawns. And as trees grow taller, root systems deepen, and ground covers are more thoroughly established, the garden--assisted by good mulching--needs less and less water.

Shaded decks as cool buffer zones;

new spaces that invite the air in

Between the garden and the house, deep roof overhangs and broad trellises now shade wooden decks, installed in place of heat-collecting concrete patios.

Additions along the house's north and south sides take advantage of prevailing winds. They use aligned pairs of sliding glass doors that, when open, let gentle breezes cool the entire house.

Increasing the house's original 1,200 square feet by 850 square feet, these new areas also create a better traffic pattern, allowing for circulation by routes other than through the living room.

Improvements for existing

temperature-control systems

The Baums also added R-30 insulation under a new roof, R-19 insulation in the walls, and double-glazed south-facing windows--and installed a ceiling fan to keep air moving on still days. They no longer need to use air conditioning unless reported temperatures reach 105[degrees].