A two-sided fireplace separates the great room from the adjacent morning room. (Photo by Alan Goldstein for Brookfield Residential)

Brookfield Residential’s Edison model at the firm’s Avendale community near Bristow, Va., is not your typical furnished sales model.

Dubbed “PureBlue” by the Brookfield team that oversaw its design and construction, this version of the Edison — a 4,100-square-foot home priced at $699,990 — has energy-saving features that place it in the upper ranks of the most energy-efficient houses in the Washington area.

The 9.94-kilowatt photovoltaic (PV) array on the roof elevates this house to an even more rarified category: net zero energy home. To qualify for this designation, a house must produce more electricity in a year than its household consumes. The excess power can be sold by the eventual owners to one of the electric utilities that operate in the Bristow area.

Energy savings will not be the only gain for the owners. They will also make money — about $200 annually. That’s because over the course of a year they will be selling more electricity to the local utility during sunlight hours than they will use after sunset when the PVs on the roof are not generating anything. The income from the electric utility will also cover their natural gas bills for heating.

By contrast, owners of a similar size house in Avendale that is built to the standards of Virginia’s mandated 2012 Model Energy Code would pay about $2,077 a year in natural gas and electricity bills, according to an estimate by Elliott Seibert of Stephen Winter Associates. Seibert analyzed the PureBlue home’s energy use and supervised the team that examined energy use of all of the homes Brookfield built in Avendale in 2015.

Energy efficiency was not the only goal of the team that developed the PureBlue in Prince William County. Taking a more holistic approach, the team also addressed water efficiency. “Gray water” from bathroom sinks, showers and a washing machine is collected, filtered, stored in a 500-gallon cistern below the outdoor deck and then piped through a drip irrigation system to shrubs that cover about 70 percent of the model home’s lot. Because the house is unoccupied, the firm has no data on the water savings that the owners can expect.

Brookfield Residential’s PureBlue Edison’s Craftsman-styled exterior has a boxy shape with a simplified roof line and only one gable on the front instead of the usual three or four for a house of this size and price. (Photo by Alan Goldstein for Brookfield Residential)

What led Brookfield to embark on the ambitious project?

The idea began with a challenge from Alan Norris, Brookfield’s chief executive, to each of the firm’s 13 divisions across the United States and Canada: Do something innovative. Each division was given a year to choose and complete a project. There were no budget constraints.

The team assembled by Brookfield’s local production manager, Marc Dalessio, decided to pursue energy and water efficiency far beyond what the local codes require and large national homebuilders generally offer. Buyers are becoming increasingly interested in these issues, Dalessio said, and the team wanted to test the feasibility of offering the efficiency features on a regular basis (the team concluded that with some modifications, they could be).

The learning curve was steep, Daleassio said. The team soon realized that extreme energy efficiency was not merely a matter of slapping on extra insulation, plugging air leaks and using three-paned windows. It required them to rethink every aspect of construction, including the shape of the house itself — the more boxy the house and the simpler the roof line, the more energy-efficient.

The Edison was their solution. Designed in consultation with architect Mark Leahy of Pinnacle Design in Fairfax, the house has no projecting bay windows, a favorite among home buyers in the area, and the roof includes only one projecting gable on the front, not the three or four that would typically adorn a house of this size and price .

Additional energy efficiencies were realized by detaching the garage from the main house. This unusual step was taken because garages, which are not insulated, are “notoriously inefficient, unconditioned spaces that suck out heat in the winter,” Seibert said. (Also unusual: The two-car garage is a $24,500 option.)

The simple shape of the building envelope is reflected in the deceptively simple floor plan for the $429,990 base-price house, which has 2,300 square feet. Rather than several rooms on the main living level, there is only one. But most visitors will not feel shortchanged because the clever design of the single large living area (a 21-by-21-foot grand room with a spacious adjoining kitchen at one end) creates the illusion of a much bigger house. Buyers who still want a multipurpose “flex” space on this floor can get the $27,500 morning room shown in the model. (To have this option, buyers must also get the second-floor expansion that nearly doubles the size of the master suite.)

The raised-bar counter is made from a slab of black walnut that was made from a tree that once stood on the development site. The cabinets are bamboo. (Photo by Alan Goldstein for Brookfield Residential)

The illusion of size begins at the front door. The 8-by-10-foot entry foyer will say to most visitors, “this house is big,” Leahy said, and the adjacent stairs that are open from the second floor to the basement below convey the spaciousness of the two-story foyers of the 1990s and 2000s “without wasting space.” With six windows in the foyer and stairwell, the entry area is flooded with natural light, which makes the space seem even bigger.

Visitors will also find that the Edison PureBlue sales model displays an unusual mix of traditional and contemporary styling.

The front elevation is clearly Craftsman, but with a twist. The curved, sloping front gable hints of fairy tales and long-ago times, while the unusual stonework suggests modern updating.

Once inside, the first thing to catch the eye is the industrial loft look of the entry area, a style not typically found in furnished, suburban, single-family sales models in the Washington area. Exposed brick in the open stairwell runs from the ceiling line of the second floor to the floor line of the basement below, and the stair rails are enclosed with thin horizontal stainless steel cables, not the clunky vertical wood spindles used by most builders.

Straight ahead and two steps down is the grand room, the heart of the house. The segue from a smaller foyer space with an eight-foot ceiling to a much larger space with a nine-foot ceiling creates a subtle “compression-expansion” sensation — straight out of the Frank Lloyd Wright playbook, and one that Leahy said he tries to incorporate whenever he can because it conveys a sense of arrival from “out there” to “in here.”

A second Frank Lloyd Wright touch in the grand room are the simple, horizontal bands of dark-stained poplar trim that run around the entire 21-by 21-foot area at the ceiling line. The trim conceals cove lighting that illuminates the ceiling at night and makes the large, 21-by 21-foot space feel more cozy. The trim also gives this large space some visual definition.

Yet another Frank Lloyd Wright-inspired detail is the $6,500 exposed-brick, two-sided fireplace that separates the grand room from the adjoining, 16-by-13 1/2 -foot morning room. The large 63-square-foot expanse of glass on each of the morning room’s two outside walls makes it a great place to start your day, and demonstrate that even with extreme energy efficiency, you can still have big windows.

The island, which separates the grand room from the kitchen, incorporates one of the PureBlue home’s most unusual features. The raised, bar-height counter on the grand room side was made from a single slab of black walnut from a tree that once stood on the site. Repurposing wood from trees that have special meaning for a homeowner is increasingly popular, and many buyers ask for it, Daleassio said.

The open stairwell that runs from the second floor to the basement conveys the spaciousness of the two-story foyers of the 1990s and 2000s "without wasting space," architect Mark Leahy said. (Photo by Alan Goldstein for Brookfield Residential)

Subtle details in the PureBlue house also make the spaces in it feel different. For example, the stairs in the entry foyer are 48 inches wide (in Washington’s new-home market they are typically 11 inches narrower), and the “family foyer” at the rear is 6 feet wide with a large window, wide enough to easily maneuver around sports equipment that younger members of the household will inevitably drop there.

The second floor has three bedrooms and a generous loft area adjacent to the stairwell that can be converted into a fourth bedroom. As shown, the loft is flooded with natural light and is one of the nicest spaces in the house. Other unusual features on this level include the optional $16,500 enclosed deck off the master bedroom, which provides a private outdoor space, and the large, five-sided shower in the expanded master bathroom. Three walls of the shower are frameless glass; the shower is so spacious that it approximates showering in the great outdoors. (The shower is about 36 square feet, roughly 2.5 times the size of large stall showers in most new houses.)

The PureBlue home’s price is $699,990, $270,000 more than the sale price for the basic 2,300-square-foot floor plan, which Brookfield also offers.

What accounts for the markup?

The energy-saving features account for about 39 percent ($105,000) of the higher price. The water-saving features account for an additional 6 percent ($17,000). The other 55 percent ($148,000) covers all the features that buyers can expect to find on any builder’s furnished sales model: additional finished space (in this case, the entire basement, the morning room, the expanded second-floor master suite, the private deck off the master suite and the garage), upgraded finishes, decorator items and extra windows.

Katherine Salant has an architecture degree from Harvard. Salant, who grew up in Fairfax County, now lives in Ann Arbor, Mich. If you have questions or would like to suggest topics for coverage, contact her at salanthousewatch@gmail.com or www.katherinesalant.com.