It’s been ages since my husband and I drove across Terhune Road. So we both exclaimed when we turned the corner at Jefferson Road and saw a brand new house. “Wow! Very cool,” was our reaction to what we thought was a stone and wood home in a style that suggested upscale Berkshires, or maybe Vermont.

Little did we know that the new house was made of straw.

My husband, a devotee of Mother Earth magazine, is forever interrupting my reading to show me spreads on houses made of bales of hay, or of yurts made of mud and God only knows what else. When I’m not too deep into a novel I try to be at least a little enthusiastic, but these dwellings look so alien that mostly I just wonder if they include indoor plumbing — and where on earth anyone is building them.

Not more than a week after first seeing the new house, I drove down Terhune, peering at house numbers looking for 135, where I had an appointment to speak with David E. Cohen, the architect/owner of a green — or environmentally-friendly — house that U.S. 1 planned to profile. It was a complete surprise to find that his house was none other than the stunning house we had spotted a week earlier.

Cohen’s house didn’t look particularly green from the curb. When he didn’t answer his door right away, I circled it once — and then again, noting the hand-made swing hanging from the big tree in front, and counting the porches — there are nine. Still, I saw nothing that looked especially green.

When Cohen finally emerged from his basement office, he led a tour, and talked about the many ways in which his new home is green. He also quickly made it clear that green isn’t what it used to be.

“There was a big boom in green building in the 1970s,” Cohen says. It was driven by an energy crisis, the same one that most people recall from waiting in miles-long lines to purchase gasoline. “Designers at that time couldn’t combine good design with green design,” he says. There are a couple of examples of 1970s green in Princeton. He talks about a house on Pine Street, designed by architect Doug Kelbaugh. “It’s rotated toward the street,” he says. “There’s a glass wall with a stone wall right behind it. Sunlight goes through the glass, heats the stone, and warms the room.”

In Cohen’s opinion, this attempt to cut energy costs resulted in little more than a “machine for creating energy,” not a livable home that blends in with its neighbors.

Cohen’s new home, on the other hand, was designed to fit into its neighborhood, and it does. It is more modern-looking than many of its split-level, 1950s neighbors, but in size, shape, and external finish it is not at all out of place. “The neat thing about green in the 21st century,” he says, “is that there is a real attempt to integrate.”

Some of the home’s green elements are obvious when you look for them, while others are hidden away — or are in the form of common building elements that just don’t exist at number 135 Terhune. The porches are the most obvious sign that something different is at the heart of the Cohen house. The absence of air conditioning compressors is another.

“Every bedroom has a sleeping porch,” says Cohen. On hot nights it will be possible to bed down with the breezes. There are also two large fans in the third floor bedroom that can completely exchange the home’s air in 10 minutes. As cool summer evenings replace scorching days, fresh air can be brought in to replace the warmer air inside. Another common sense, low-tech cooling element is the roof overhangs that keep the sun off bedroom windows during the heat of the day.

As is the case with the vast majority of Princeton homes, Cohen’s property has many trees. He points out that keeping them on the lot means that there will be shade in the summer — and cooler air, too.

Cohen chose not to install solar panels, a hot greening tool. He says that the trees are actually better energy savers. Really? Yes, Cohen replies, explaining that “because of transpiration, it is 10 degrees cooler under the trees. They cool the whole environment.”

He had to choose one or the other — trees or solar panels. The trees would block the sun from the southern sky, and make the panels ineffective. What’s more, he says, New Jersey, which provides tax credits for the installation of the panels, will not do so if trees are cut down to let the sun reach them.

Using sleeping porches and trees to cool down a house involves tapping into centuries-old, common sense building practices — practices that were discarded as air conditioning became widely available. Another common sense cooling strategy that Cohen uses involves taking full advantage of cross ventilation. Walk into the front door of his open floor plan house and you are in — or within steps of — the foyer, living room, dining room, kitchen, and sun room. Look around from any point and you see windows — lots and lots of windows — on every wall. If there is a breath of air anywhere, coming from any direction, it will find its way into the house.

While the cooling elements of the Cohen house can be found in many a 1900s farm house or vacation cottage, some are brand new, and still very unusual.

The walls are indeed made of straw. Manufactured at just one plant in Texas, the wall system Cohen used consists of pre-fab panels stuffed with agricultural waste straw book-ended by sheets of recycled wood particles. They come in four or eight-inch widths, and serve as framing, insulation, sheathing, and sheet rock. “The panels can be up to 9-feet tall and 28-feet long,” says Cohen, who used the wider panels for outside walls, and the more narrow panels for interior walls.

The panels are cut in the factory to specifications sent by the builder. Once on-site, they are difficult to reconfigure, so it is vital to measure carefully. “I sent the plans and went back and forth with the factory three or four times,” says Cohen.

Were there errors? Yes, two. “Luckily, the panels were too big, not too small,” he says. It is possible to cut the panels down, but it’s not easy, in large part because of the way they are sealed. “You have to take the straw out, and re-insert the edging,” he says. “If they were too small, I don’t know what we would have done.” Still, he points out, “we used 110 panels, and only had to modify two.”

Advantages of the straw-filled panels include superior insulation, greater fire retardation properties, and freedom from the formaldehyde that is often used in the manufacture of insulation and sheetrock. The panels are more expensive than the materials they replace, but Cohen says that, having put up one house using the system, he will be able to cut costs on future projects. A lot of the extra cost came from the labor of working the heavy panels into the second and third floors and threading in the plumbing and electric. A one story house would be a snap to build with the panels, he says, and he is confident that the next two or three-story home he builds will go up much more smoothly.

Other green elements of the Cohen house include compact fluorescent light bulbs in every fixture, except for the ceiling fans, which came with halogen bulbs. There have been complaints that the energy-saving bulbs come on too slowly, but Cohen, who has been in his new house for nearly two months, is finding that some come on to full brightness instantly, while others do have a delay, but only of a minute or two. “It hasn’t been a problem,” he says. “The light quality of compact fluorescents has improved so much over the last 10 years.”

The house’s interior walls have been painted with zero VOC — volatile organic compound — paint. “The standard now is that you should be able to eat the paint,” he says with a laugh. But he’s not joking. His paint is indeed edible.

His floors are made of cork. Nice looking and pleasantly bouncy, no trees are felled to harvest it. Cork is stripped from just part of a tree, while the tree itself is left healthy and standing. The material is in increasing demand in green circles, as evidenced by the fact that the price for the flooring went up 50 percent during the time it took Cohen to take his house from plan to completion. That put the cork floors at just about the price point of hardwood flooring.

Cabinets throughout the house are made of 100 percent recycled, formaldehyde-free particle board. “Some people paint them,” says Cohen, “but we chose not to.” Dark and smooth, they look handsome, and cost about what maple cabinets would.

Green building, still in its infancy, is a response to a number of issues, including energy use, the preservation of scarce resources, and health. Sometimes all three come together, as is the case with the wall panels in the Cohen home. The paint, however, is a direct response to health concerns, as are the cabinets to some extent. Serious, understated, and thoughtful, Cohen says that the chemicals, some of them possible carcinogens, that building materials release into most homes are probably not harmful to most people. After all, he says, “some people smoke for their whole lives, and never get cancer.”

But for people who are sensitive to chemicals, indoor air can lead to disability. Cohen suspects that his own mother, who suffers from chronic fatigue syndrome, may be a victim of toxic indoor air. “She’s housebound now,” he says, “but when she was able to travel, she always felt better than she did when she was at home.” It’s possible, he continues, that the chemicals in indoor air cause many people to become sick, but that a large percentage of these people never suspect anything as benign-looking as wallboard, carpets, cabinets, or the nice taupe paint on the living room walls.

While Cohen did not compromise by using any materials suspected of containing toxic chemicals, cost did force some compromises in his 3,000-square-foot house, which was completed at a cost of $750,000.

“We used double-pane windows with a light tint,” he says. “We could have used triple-pane windows.” He says that he also could have used windows filled with argon or krypton gas. These measures would have provided better insulation, but also would have cost significantly more, and windows he used were already very expensive. He also could have chosen to heat his house with a geothermal pump.

But the pumps, generally used for both air conditioning and heating, are far more expensive than a standard furnace, and result in less energy savings in a house where design features have done away with the need for air conditioners. “It didn’t seem that there would be much of a pay-off,” says Cohen. “We made the decision to use radiant heat, and to go with oil rather than gas. That may seem like a strange choice, but I’m looking forward to the time when biodiesel will be available.” Meanwhile, although it is still early days, he is sure that his heating bills are about half what they would have been in a conventional house.

In addition to compromises necessitated by cost, there were compromises based on esthetics. Those sleeping porches do not have screens, for example. Won’t they be unbearably buggy on August nights? Quite possibly, Cohen admits, but he points out that they are recessed into the house and that they could be hung with mosquito nets. The decision not to screen them was made with an eye toward the home’s appearance.

One place where Cohen decided not to compromise was the roof. He had originally planned to cover it with asphalt shingles, but, after researching the material, he learned that it gives off volatile organic compounds when the sun heats it up. He ended up choosing cedar shakes instead, despite the fact that they cost twice as much.

The greening at 135 Terhune will continue outdoors. Cohen is working with Princeton landscape designer Henry Arnold, author of “Trees in Urban Design,” to create an environmentally-sound space around his green house. “The first point is to use native plants,” says Cohen. Then there is the issue of dealing with storm water. “You don’t want too much hardscape,” he says. “It causes run-off.” Green design seeks to keep rainfall on site, possibly in a water garden, or, perhaps in barrels, which can be tapped to water grass and plants during a drought.

Cohen, a graduate of Harvard (Class of 1980) and of the School of Architecture at the University of Virginia, sees his home as a comfortable shelter for his family. His wife, Liz, is a social worker with Princeton Healthcare System’s hospice program. Their oldest child, Molly, is studying Russian literature at Reed College. Ethan, who is nearly 18, is about to graduate from Princeton High School, where his younger brother, Sim, age 14, is headed in September.

But the house is also a showcase for green building. Cohen, who went out on his own, forming DEC Architects LLC in 2002 after working for Michael Landau Associates and CUH2A, hopes to spend the majority of his time building green homes for other families. Right now his practice consists of some commercial work, including the design of Booster Juice, which is slated to open at 166 Nassau Street in July, lots of residential work, including many additions and renovations, and a number of “worship” environment projects, mostly synagogues.

He says that he wouldn’t want to completely give up any of those niches, as he enjoys designing for all of them, but he is deeply interested in green design, and wants to move in that direction.

The deceptively radical house at 135 Terhune has an interesting — and totally fraught — back story. Cohen bought the house next door 10 years ago. The contract he signed with the owners included the stipulation that he would be able to sub-divide the large lot. It took him four full years to get permission from Princeton Township to do so. And then, approval in hand, he, or rather the owners of the house in which he was living, but on which he had not yet closed, were sued by a neighbor who was opposed to the subdivision. That case dragged on through the courts for six years. Cohen, who, at least after the fact, seems almost Zen-like in accepting the delay, says that his legal costs were “only $75,000.” The costs for the house’s owners were far higher.

Like many Princeton houses, the house in which he and his family lived for 10 years, the one next door to his new green house, looks like a large single family home, but it is really a duplex. Cohen has now sold both halves, one to the family who had been his tenants, and with whom he had become close friends.

All has ended well for Cohen and his green house, but with piles of construction dirt still encircling his home, he is about to be immersed in construction dust and noise once again. Very close to his house, construction on a new home is about to begin. Roman Barsky, the busy Princeton builder who has just completed a little community of luxury homes, Barsky Court, just behind 302 Nassau Street, is breaking ground for another house. The bad news is that Cohen had hoped to work with Barsky on the project, but that the plan didn’t quite come together. The good news is that Barsky, accustomed to putting up houses in Princeton, will most likely work efficiently, and get the project finished quickly, so that the Cohens will be able, at last, to enjoy dust-free living.

Pulling away from 135 Terhune, I realize that not only did I utterly fail to notice its green elements when I first saw it, but that I was also half-wrong on even the basics of its exterior. What appears to be a wood and stone exterior is really a stone, cement, and newspaper exterior. The first story is sheathed in local rock, but the second story is made of cement and recycled newspaper shaped into planks that look exactly like wood, but that require almost no maintenance.

While few people who drive or stroll by will notice that the new house is different in any way, Cohen sees it as an opening salvo in a revolution as grand and far-reaching as that spawned by the introduction of computers, and then of the Internet. It will create jobs, and change the way materials are made, the way people work, and even the way that they think. “Green,” says Cohen, “is the future.”

DEC Architects, 135 Terhune Road, Princeton 08540. David Cohen. 609-252-9477; fax, 732-783-0310. E-mail:

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