For Simon and Janet Katz, getting away to their second home used to mean a four-and-a-half hour trip. “When our four kids were young, we had a house in Vermont, because we did a lot of skiing as a family,” says Janet. “But skiing got less important, and the long drive got to be a grind.”

The well-traveled couple wanted easier access to Manhattan, but didn’t want to sacrifice beauty or tranquility. On the Hudson’s east bank, in Columbia County, they found a site that moved them: a slope of hillside overlooking the river, the Catskills rolling away to infinity in the distance beyond, with the whistle and throb of the train, the rustle of the leaves in the river breeze, and birdcalls for background music.

“The river sparkles. It’s always changing—the light, the traffic—it vitalizes the entire house,” Janet says. “In winter, when the leaves fall, it’s like the river is right there. It’s taken the place of the mountain views for us. We have Hudson right near by, and the downtown is great—excellent entertainment venues, terrific restaurants, interesting antique stores—and we’re only a mile from Amtrak. In half an hour, we can be in Woodstock.”

Having found their location, Simon and Janet worked with the husband and wife architectural team of Karin and James Lyman Reynolds on a design that would fit both the challenging site and their personal style.

“Being an artist and an art lover, [Janet] wanted something non-traditional, and it was great to work with people with that kind of sensibility,” says Karin. “We started with Styrofoam and cardboard models and just played around with the rooflines, and ways to get light and river views. Once we had the basic volumes right, we started to cut out an abstract shape.”

The result commands its terraced site on the hillside, the warm gray/beige of the vertical cedar siding blending with the wooded backdrop while the ultramodern lines and angles lend grandeur without ostentation—abstract yet somehow homey and inviting.

“A lot of the design process was her initiative,” says Karin Reynolds of Janet. “It’s teamwork, when it goes well. As architects, we’re there to help people realize their vision and get what they want. On some jobs, we get excited too. It’s rare to find someone with that artistic vision and breadth of travel experience.”

Janet relates that “When we started talking about the plan, we had lots of technical questions. When this first started, we didn’t really have a building site, even—just a hillside. We needed someone to make us more confident in what we were about to do.”

A cozy entry hall leads into an open floor plan with a ceiling sloping from one story high facing the river to two stories, offering a wall capable of showcasing Janet’s beloved art and lit indirectly, partly by a high row of clerestory windows on the eastern exposure. The magnitude of the collection—imposing pieces such as The Women, an acrylic on canvas by Joseph Hirsch that measures 65 by 114 inches— would overwhelm a more traditional room. Here, among sculptural elements and serving as one focal point of the sweeping expanse, The Women and several other striking, carefully chosen works appear comfortably at home. “When I first told James I wanted a place to hang these paintings, I think he thought I was crazy,” Janet chuckles. “I’ve had some of these pieces for many years.”

The ultimate stunner, of course, is the panorama of river and mountain range, and it is framed and reframed through a series of energy-efficient triple-glazed windows.

A zero-clearance limestone-tiled fireplace anchors a comfy living area, with a 36’ Glu-Lam (glued and laminated) beam spanning the ceiling on either side. “You don’t see those used residentially so much, but the size called for it,” says James Reynolds.

The kitchen opens onto a screened breakfast nook adjacent to Janet’s kitchen garden. At the other end of the house, the master suite is simple and charming, with its own views—aside from the downstairs laundry room and one half-bath near the entrance, no part of the house is without a spectacular view—and homey touches: a handsome built-in cedar chest of drawers, a four-poster bed. Throughout, the interior finish is clean and sleek, with floors of white oak—and the length of the house is tied together by a deck of sustainably harvested and extremely durable ipe hardwood.

The lower level provides another 2,200 square feet of comfy living space, broken into two roomy suites and a central relaxation zone. Windows and sliders access still more gorgeous views and open to a stone patio with a sunken lap pool. One of two downstairs baths features a steam room. “Putting the additional living space underneath, instead of adding a floor, kept the costs to about 50 cents on the dollar,” says James. “But we wanted to make sure it didn’t feel like a basement.” A free-form cement column ties together the main level’s deck and the patio beneath; a pergola roof protects the pool hardware. The upper story of the garage houses Janet’s pottery studio.

Smooth-finished cement tiles channel radiant heat. A geothermal system was initially considered, but drilling costs would have added some $40,000 to the price tag. Instead, the Katzes went with a state-of-the-art propane-fired hot air system and installed a 5 kilowatt photovoltaic system on the roof, which provides electricity and some of the hot water heating. Icynene spray foam insulation, with its high efficiency and low-VOC (volatile organic compound) features, makes for a tight, efficient envelope; a ducted HVAC system provides interior climate control, and an energy-recovery ventilation system ensures fresh air.

“We tried very hard to make it as green as possible,” says Janet. “James was very cognizant of that. We all worked very well together—some architects have preconceived notions binding them. That didn’t happen here. He listened well, took us seriously, and translated our needs into a house.”

It’s easy to visualize some or all of the 11 Katz grandchildren splashing in the pool, helping in the garden, or enjoying a boisterous kid-fest in the spacious downstairs whilst the adults take their leisure on the upper deck. And it’s that next generation Janet speaks of when asked why energy efficiency was a top priority. “It would have been less expensive not to go green, but we made up our minds to do it, and it became one of the things we really love about the house. It’s thrilling to realize that we are generating our own electricity.

“The world is changing, and with 11 beautiful grandchildren, the future is much on our minds. From that perspective, I don’t see how you could be anything but conscious of the environment.”