Passive survivability makes homes livable in extreme conditions
Last winter, an ice storm hit Dallas, taking down power lines throughout the city. In Gary Gene Olp's neighborhood, all of his neighbors had to vacate their frigid homes, but Olp's family stayed put.
The Olp family was able to stay in their 3,600-square-foot home, despite the power outage, because Olp designed the home to maintain livable conditions in extreme weather conditions. For instance, the home is heavily insulated, so the temperature never dropped below 67 degrees indoors at night during the power outage, and as soon as the family was up and a fireplace was lit, the home stayed at a comfortable 71 degrees each day, Olp said.
Passive survivability means that a building can maintain livable conditions in the event of an extended power outage, fuel supply interruption or water shortage. Passive survivability is important in all areas, whether the region is hit with snow, ice or hurricanes. This need is increasing as scientists predict that with global climate change there will be more intense storms and, as a result, more power outages.
Olp, the founder and principal of GGO Architects in Dallas, said, "The way the house is designed, the air moves through it and the house stays warm. It was kind of fun last winter. We brought in Coleman lanterns and candles because we had no light, but we had a gas cooktop and a gas stove and we're campers anyway. But through a passive survivability standpoint, my house was able to weather the situation."
His home is also staying cool this summer while temperatures are topping 110 degrees in Dallas. Air conditioning is only turned on at night, during off-peak rates, to cool the air to 68 degrees, and during the day, when air conditioning is not used, the indoor temperature is never more than 74 or 75 degrees.
"We could weather these extremes simply by the effect of the conscious design decisions I made in the construction of the home. The way many people's homes are designed is that within hours after a power outage in summer, the temperature inside the home is higher than outside," Olp said.
Passive survivability design is important with power outages common in severe weather. A few key elements of passive survivability include the structure being able to withstand high winds, plenty of natural light, renewable energy options such as solar or wind power, water storage and passive solar design.
Summer vs. winter
Passive solar design keeps the Olp home cool in the summer, and warm in the winter, due to several components. The home uses trees to shade the roof, which is passive solar, as well as a roof Olp designed that mitigates 75 to 80 percent of the heat gain away from the home.
It's important to remember that there are passive solar techniques to be used in the summer that differ from the winter. "You know the sun is going to pound the west side roof and side of those structures, so you deliberately design structures to welcome that in the winter and avoid it in the summer," he said.
There is a living wall on the west side of Olp's home and he refers to it as a "super structure" that sits about two feet away from the actual west wall of the house. In the summer, jasmine and climbing roses on the super structure create shade as well as lowering the temperature with moisture as it evaporates from the plants. In the winter, those plants are gone, so the west wall is fully exposed to the sun to warm the home.
Olp has built homes with passive sustainability in colder climates such as Colorado and Maine, too. "It's applicable in any region. We used a dark colored roof to absorb the heat in Colorado, and in Dallas, we do reflective roofs to shed the heat."
Consider thermal mass
Another consideration is thermal mass, especially in regard to the stability of indoor temperatures during the day versus at night, said Ted Clifton, founder of Zero-Energy Plans LLC and CVH Inc., as well as a ProudGreenHome Approved Contributing Expert.
"This is especially important in more extreme climates, like those in Dallas or in colder northern areas of the country. Many homes in Texas are on slabs, but a slab floor is not the only way to achieve thermal mass within a building envelope," Clifton said. "Most stairwells in commercial and institutional buildings are of concrete construction. This is purely for fire egress, but there is no reason not to have this level of safety in a residence as well, and locate the stairwell where it will optimize absorption of solar radiation. This will help cool in the summer, and help heat in the winter, and provide stabilization from day-to-night temperature swings year 'round."
Another way to achieve thermal mass is putting tile backer board and heavy slate tile on a wood-framed floor. "Rock, stone, concrete, or brick will store about seven times as much heat per volume of material as wood or any similar composite or material. This extra stored heat can make the difference between running out of heat inside the home during a power outage at 10 p.m., or making it through to 8 a.m., when the sun is up, and beginning to re-heat the house," Clifton said.
Survivability need is increasing
Clifton points out the recent earthquake in Japan as showing the importance of survivability.
"A relatively few — tens of thousands — of homes were destroyed by the direct impacts of the earthquake and tsunami, but many millions were without power for a very extended period of time. As the pressure on our energy supplies increases, even without the onset of more natural disasters, we will see more rolling blackouts, fuel shortages, limits on power use during peak periods, etc. The more we can become self-sufficient during those times, the less of an intrusion into our lifestyle it will be when it happens. For the elderly and those of fragile health, it could be the difference between life and death."
Please see this slideshow of images of homes with passive survivability that Gary Gene Olp has designed.
Teena Hammond Teena Hammond has published more than 2,000 articles in People and W magazines, Women's Wear Daily, and in dozens of newspapers and books. She also wrote a home improvement, remodeling and decor column that ran in Gannett newspapers nationwide. She's interested in all things green and would love to hear from you with your story ideas.