List Price: $5.499 million
The Property: This is a big house; it’s 15,000 square feet. And it’s on a very big property, five acres of tall oak trees on a knoll in Lake Forest. The house maximizes its site: It’s curved so that every room has a different view out into the trees, and it basks in the sun.

The outdoors follows you in, not only because there are tall walls of glass in the sitting room and dining room that flank the front entry, but thanks to a row of indoor plantings that extend the landscape inside. There are further reminders of the outdoors: In the dining room is a fluid wall of etched glass that suggests water, and in the sitting room there’s actual water via an indoor waterfall.

“When you walk through the front door, it’s not like you’ve stepped inside a building,” Rajul Bhalala, who with her husband, Gopal Bhalala, bought the home in 2004, told me. “You feel as if you’re still outdoors.”

The house is finished with a very contemporary look, but you can see the finishes as an abstraction on the natural setting: columns that pick up the tree trunks outside, and extensive use of natural materials—wood and stone.

In the very large south-facing living room, you have a high ceiling and walls of windows that take you right out into the site. That was the point in the mid-1930s, when George Fred Keck designed the original part of this house: getting occupants out into the natural setting. The south wall of windows curves, and not just because there’s a pretty view out over the knoll the home stands on.

It’s also because Keck was a pioneer of passive solar design. There’s a deep overhang outside the south first floor’s south windows. In autumn and winter, as the sun falls lower in the sky, daylight and warmth come into the rooms. But in the summer, when the sun sits above the house, it doesn’t get in and warm the space.

The estate was originally a summer home, on 30 acres. The lot has gotten smaller—it’s five acres now—but the house has grown, with expansions on the main floor and a new level added above. When those additions were made in the mid-1990s, the house grew to have seven bedrooms and nine full baths, but that original idea of maintaining a connection with the outdoors was preserved, and even enhanced.

The two-story walls of glass on new section create an atrium-like feeling. And the second-story master suite is an elongated space with nature spread out on the other side of a wall of windows.

The master is a long stretch of space that incorporates a bedroom, fireplace, sitting room, office, bathroom, and another sitting room, all separated by partial walls to allow for an uninterrupted view out over the beautiful setting. I’m told that we arrived to shoot video about a week and a half too late to see the colors of the fall foliage light up the inside of the house. That’s something that changes, of course, throughout the year. Rajul Bhalala told me that it’s not only the movement of the sun, as Keck set the house up to accommodate, but that the change of seasons changes the look of the interior’s expansive white walls. In the summer, when the sun is high, it’s cool and serene inside, but in fall you get all those bright colors, and in winter, because there’s so little delineation between indoors and out, when a snowfall blankets the grouns it’s going to feel like you’re in your own snow palace.

Price Points: Listing agent Sheila Brooks notes that the passive solar design reduces operating costs of the home: heating in winter or cooling in summer costs around $700 a month, which is a small fraction of what a standard 15,000-square-footer would require. And the home’s roof was designed to accommodate solar panels in such a way that they won’t intrude on neighbors’ views. A solar setup up there, the Bhalalas have been told by estimators, would generate enough energy to power both the home and Lake Forest Country Day School, next door.

The sellers paid $4.9 million for the estate in 2004, according to public records. Their asking price represents a 12-percent profit on their purchase price.

Listing Agent: Sheila Brooks and Todd Martin of Prudential Rubloff. Brooks: 847-557-3460 and sbrooks@rubloff.com. Martin: 847-557-3461 and tmartin@rubloff.com