Mainstream Green

Peter Pfeiffer seldom needs to sell the concept of sustainable architecture, but he can make a very convincing case when he has to. “We've been around so long that people come to us with a similar ideology,” says Pfeiffer, who attributes the majority of his clientele to “the graying of the green Baby Boomers.” But, he adds, “A lot of the houses we've done are for big Texas oil executives.” The latter group might not sit still for a sermon on the fate of the earth, and Pfeiffer sees no need for one. Rather than appeal to their altruism or sense of collective guilt, he simply explains why building one of the greenest houses in the country is also building the best house for the money. Compared with an ordinary custom home, Pfeiffer says, one designed with the proper concern for sustainability is more durable, less expensive to operate and maintain, more comfortable, and a healthier place to live. “And, by the way,” he adds, “the additional cost is 2 to 3 percent over the cost of a conventional home.” He puts the matter in terms that most Americans will readily grasp. “Do you want to

Pfeiffer's own home, which blends Mission and Texas Hill Country architectural styles, houses both an active family life and a living laboratory of sustainable design. Photo: Connie Moberley build a big Ford Econoline with leather seats, or do you want an Audi or a Mercedes?” The approach works. While architects and builders around the country complain that their clients won't invest in sustainability, Pfeiffer's firm has for nearly 20 years designed nothing but green buildings. “I think the reason why everything we do could be called very green is that we've learned to articulate the value of being green,” says Pfeiffer, who with partner Alan Barley founded Barley & Pfeiffer Architects in 1987. At the beginning, not every potential client who walked through the door was impressed. “Three out of four were only interested in a ‘Texas Tuscan,'” he recalls, referring to a local breed of trophy house. But enough responded that the partners knew they were on to something. When these clients learned about the kind of house they could have—energy- and resource-efficient, tuned to its surroundings, technologically advanced, comfortable, and beautiful—“Their eyes would light up.” Over the years, that core group has grown, along with the firm's reputation and its ability to deliver ever more highly developed buildings. And, true to Pfeiffer's belief in the broad appeal of green building, they represent a cross-section of the home-buying population. Parents respond to the idea of a house that is safer for their children. “Your kids will get sick less often,” Pfeiffer promises. “You'll get sick less often.” Empty nesters, even those who can afford a custom home, prefer one that operates “at $75 a month instead of $250 a month.” Regardless of their ideology or politics, Pfeiffer's clients can approach this as a straightforward consumer decision. They see a better house, and that's the house they want.

The building's central stair tower serves as a light well and a convective chimney that draws a stream of natural ventilation through the house. Photo: Connie Moberley The house they get reflects a systematic energy efficiency program that begins with the basics and moves on to more sophisticated technology, guided throughout by precise computer analysis. A Barley & Pfeiffer building is sited with careful consideration of solar angles, prevailing breezes, and natural shade. Roof overhangs shield windows during the warmer months, cutting the air conditioning load and reducing operating costs. The building shell is well-insulated and exceptionally tight (typically less than one-quarter of an air change per hour). Walls are well-sealed against moisture transfer (in Pfeiffer's region, where the air conditioning season lasts more than half the year, vapor tends to move from outside to inside). Mechanical systems combine high-efficiency components, commonsense design, and meticulous installation.

One of the rewarding aspects of this comprehensive approach is that the benefits tend to reinforce each other, generating a cost-saving reverse domino effect. Indirect day lighting and balanced-spectrum fluorescent light fixtures cut electricity consumption, but they also reduce the amount of waste heat flowing into the house, reducing the load on the air conditioning system and saving more money. Reduce the air conditioning load enough and you can cool the house with a smaller system, saving still more money. You don't have to be worried about power plant carbon emissions to get hooked on this kind of thing.

But making the right moves—and avoiding investments that won't pay off—is a bit more complex than it looks. When Pfeiffer first began to work in the field of sustainable design, the analysis of energy use in buildings was an empty page. Common practice out in the field, he says, was “the buckshot approach.” Designers and builders tried super-insulation, multi-glazed windows, a grab bag of solar strategies for space and water heating. Some ideas worked better than others, but as for the relative value of alternative approaches, Pfeiffer says, “We really didn't know.” But he would help to find out. At the University of Texas, where Pfeiffer added a graduate architecture degree to his bachelor's in building sciences from Rensselaer Polytechnic, he helped develop one of the earliest computer programs for analyzing energy use in buildings. “That's when we started to realize that in Austin, Texas, the walls weren't really that important.” Single-pane windows with proper overhangs performed better from an energy-use standpoint than triple-pane windows with no overhangs. The lesson—to base design decisions on hard data—stayed with him. “You've got to look at the building as a system,” Pfeiffer says, “and not waste time chasing these silver bullets that don't have the paybacks that they're supposed to.”

Pfeiffer's A/C system uses this outdoor pool as a heat sink, cooling the house and warming the swimming water in a single operation. Photo: Connie Moberley When Pfeiffer moved to Austin from the East Coast, he says, “I didn't know that I was planting myself where the green building movement was really going to take root.” But that is the way things turned out, and he showed up at a pivotal moment for the city's relationship with the environment. With demand for electricity growing and the power company shopping around for a nuclear plant, the city opted instead for a program of rebates on energy-efficient appliances. The need to limit water consumption yielded a similar demand-side solution: promoting the use of rooftop water collection, low-flow toilets, and no-water landscaping to stretch the city's allotted draw from the overtaxed Colorado River. The city headed off a looming solid-waste disposal problem with a comprehensive recycling program and measures that encouraged builders to reduce the volume of construction debris going into landfills. A member of the city's Resource Management Commission for almost 10 years, Pfeiffer relates this history with a certain pride. In the 24 years since the energy rebate program began, the city's population has tripled. “And we still haven't had to build that power plant. We didn't have to build a new landfill, and we didn't have to build a new treatment plant.” The appliance rebate program became the model for the federal Energy Star program, and Austin's Green Builder Program—which Pfeiffer served as an advisor—is the oldest and most influential in the country. Some might read the narrative above as more evidence of Austin's reputation as a bastion of liberalism. But Pfeiffer sees things differently. The city's choices reflect pragmatism as much as idealism. They came, he says, “Not through altruism, but from real problems and being up against the wall.” And they have worked. For that reason alone, Austin might well serve as a model for the rest of the country, which is rapidly backing up against its own wall. Not everyone wants to acknowledge that fact, much less take the actions that seem necessary to stave off a harsh reckoning. But as Pfeiffer has shown, doing the right thing in a custom home requires only awareness, not a significant sacrifice.

His own new house makes that case convincingly. A Craftsman-style building with a distinct Texas Hill Country flavor, it was conceived as something of a laboratory of sustainable building. Still, as in all of Pfeiffer's buildings, much of the structure's effectiveness comes from its lowest-tech features: siting and basic architecture. The house is oriented along an east-west axis to capture the prevailing southeast breezes. Windows are located for winter solar gain, with overhangs sized for summer shading. A screened porch takes advantage of cool breezes from a nearby green belt. Pfeiffer serves as a consultant to some large-scale production builders, and he urges them to take such low-hanging fruit first. The builder who focuses exclusively on high-tech materials and systems, he says, “is missing the boat on the biggest payback of all, which is a site-specific design.” Even stock plans can benefit from this approach. “It doesn't have to be a total one-off design. You take Plan 247 and face it west and it will need 2 tons of A/C. Face it south and it will need 3 tons.” Any plan can be built using engineered-wood structural components, energy-efficient appliances and lighting, low-VOC interior finishes, and a plumbing layout that puts the water heater close to the points of use.

Pfeiffer's house, of course, goes much further. A central stair tower designed as a light well and heat chimney bounces indirect daylight into the core of the house, lessening the need for artificial light, and generates a convective ventilation stream. A sealed whole-house fan shortens the air conditioning season by charging the house with outside air on cool spring and fall evenings. A metal roof with a radiant barrier at the sheathing plane and ventilation paths directly beneath the roofing keeps the sealed (rather than ventilated) attic 40 to 50 degrees cooler during the summer than typical houses in the area. A meticulously sealed ducting system minimizes energy loss through leakage and ensures even cooling. The locally manufactured air conditioning system includes a cooling tower, like those used on commercial buildings, that employs evaporative cooling to improve efficiency (most of the water for the cooling tower and landscape watering comes from a rooftop rainwater collection system). A second heat-exchange loop uses the swimming pool as a heat sink, warming the pool water and further boosting air conditioning efficiency. As a result, the house requires 40 percent less cooling capacity per square foot than the industry standard. The heating system is equally well thought-out, with a 94-percent-efficient 50-gallon gas water heater feeding hydronic air handlers (and supplying all the domestic hot water for a six-person household). Pfeiffer reports that the house has performed as his computer model predicted: monthly electrical and gas costs average $200 per month, what one would expect of a house one-third the size.

Because he viewed it as something of a test-bed, Pfeiffer went further with his own house than he might have with a typical client's—to the point of installing a gray water-recovery system (which he found less useful than a good rainwater-collection system)—but not by much. The architect may live and breathe sustainable design, but he shares his home with a wife and four kids who have other things on their minds. The same might be said of his clients, for whom—no matter how green their hearts—a house is still a home, not a hobby. They expect all the user-friendliness of a conventionally built house, but they seek Pfeiffer out because they want something more. “The vast majority, probably 90 percent,” he says, “have built a house before and don't want to repeat the mistakes they made,” most of which fall into the category of building bigger rather than smarter.

Pfeiffer believes that any discerning homeowner with enough information can make that distinction. He tells the story of a successful real estate broker, a participant in several conventional developments of upscale single-family homes, who surprised him by hiring him to design her own house. “This is a house I want to be in for a long time,” she explained. “I've got to get serious and do this one smart.” She came to the right place.

Flow Through

Natural ventilation and passive solar controls take a (cooling) load off.

Pfeiffer has plenty of high-tech/low-energy expertise up his sleeve. But before applying any whiz-bang technology to a house, he pockets the greater gains to be had by working with the elements rather than against them. Proper orientation, shading, and natural ventilation minimize air conditioning, heat, and lighting loads, easing the burden on mechanical systems. (The insulated building envelope is shown in red.) Click here to view illustration.

Passive Aggressive

Site-specific design and high-efficiency mechanical systems get more bang per BTU.

The house's mechanical systems combine active and passive approaches—and common sense—to conserve energy. A cooling tower evaporates rainwater collected from the roof to boost A/C efficiency. The HVAC system draws fresh air from the windward side of the house; the HVAC, central vacuum, and dryer vent to the downwind side. The water heater is centrally located, to prevent heat loss on the way to the tap. Click here to view illustration.

Pfeiffer's Best (Green) Practices

Orientation

Orient buildings on an east-west axis to capture solar gain and minimize summer afternoon overheating.

Locate windows to admit prevailing breezes in spring, summer, and fall. Infiltration

Install a vapor retarder on the warm side of the wall (inside in the north; outside in the south).

Maintain indoor relative humidity between 35 percent and 50 percent.

Use 30-pound building felt in conjunction with commercial-grade building wrap, well taped.

Minimize recessed lighting fixtures and electrical boxes on outside walls.

Sprayed foam and wet-blown cellulose insulation (along with good sealing practices) create a tighter wall and better indoor air quality than batt insulation.

In high-humidity areas, seal attic spaces and provide a passive ventilation path directly beneath the roof decking. Vent the roof, not the attic. Passive Cooling

Avoid dark roofing materials that absorb heat.

In warmer areas, shade all east-, south-, and especially west-facing windows from the spring, fall, and summer sun.

Install a radiant barrier, with an air space immediately beneath it, on the underside of the roof. Lighting

Use fluorescent lamps, which burn cooler and last longer than incandescent bulbs and draw a quarter of the electricity. Current versions produce superior-quality light.

Avoid halogen lamps, whose high heat output makes air conditioning systems work harder.

Plan for indirect day lighting, which can save energy, reduce glare, and increase comfort. High windows can also siphon heat out of a building in spring and fall. Mechanical

Avoid oversized air conditioning systems, which can cause mold growth in ducts and elsewhere in the house. A properly designed and constructed house should require 1 ton of cooling per 650 to 850 square feet.

Carefully seal all HVAC ducts. Leaky ducts are energy thieves and can depressurize the house, leading to excess humidity, mold growth, and other indoor air quality problems.

Place water heaters close to the point of use. This saves energy, reduces installation cost, and eliminates the need for recirculation pumps.

Use the right size water heater. A high-output 50-gallon water heater will produce the same amount of hot water as a 75-gallon standard unit, and it will do it more efficiently. Indoor Air Quality

Use mechanical barriers rather than chemical treatments against termites and other insects.

Where insects are a particular problem, spray the building's frame with a borate solution or use borate-based cellulose insulation.

Use low-VOC latex paints on interior surfaces.

Install automatic timers on all exhaust fans to avoid creating negative air pressure and excess humidity in the house, especially in warmer climates.

Air out new carpeting for a day or two before bringing it into the house.

Specify front-loading clothes washers, which add less humidity to the air than top-loading units.

Case Closed

A sealed attic stays free of moisture—and mold—in a hot, humid climate.

Rather than ventilate with hot, humid air, Pfeiffer seals his attics and ventilates a plane between the sheathing and metal roofing. The technique fights condensation and reduces summer attic temperatures by 40 to 50 degrees.