Brightly colored live sedum — a flowering plant — thrives in several inches of elevated soil on the roof, lowering the house’s indoor temperature. (Photo by Paul Pavot)

At just 3,100 square feet, this compact Arlington home on North Nottingham Street was built to be the epitome of efficient living.

Its Mansard roof is covered in live plants, much of the house’s interior is made from recycled materials and the floor plan is organized with modern residents in mind. The home is only the fourth in Arlington to gain a Gold-level National Association of Home Builders rating from Arlington County’s Green Home Choice Program, according to builder Andrew Moore, president of Arlington Designer Homes.

The house’s Home Energy Rating System index, which indicates energy efficiency based on factors including insulation and heating, is 57 — meaning it is 46 percent more energy efficient than a standard new home. This efficiency could save owners about $4,000 a year, Moore said.

“It’s the house of the future,” Moore said. “We’re probably 20 to 30 years ahead of the building codes.”

The energy efficiency begins with its green roof, built by LiveRoof, a Michigan-based designer and installer of hybrid roof systems. Brightly colored live sedum — a flowering plant — thrives in several inches of elevated soil, lowering the house’s indoor temperature by up to about eight degrees. The soil absorbs rainwater and can improve the overall life of the roof by up to 400 percent, Moore said.

The kitchen is adjacent to the detached two-car garage. (Photo by Paul Pavot)

The home was built in an attempt to reduce run-off, Moore said — with the roof, the site retains more water post-construction than pre-construction.

Inside, the house has pre-finished flooring, and the paint is free of volatile-organic compounds. The drywall, sub-flooring and insulation are made from recycled materials — doors and windows are built to minimize air leakage.

The first floor’s living room feeds into a kitchen which is adjacent to the detached two-car garage so residents can bring groceries directly into the kitchen, Moore said. An office is also on the first floor. There are four bedrooms, 31 / 2 bathrooms and an au pair suite.

The organization of the house is “utilitarian” while remaining Neocolonial, Moore said — the stairs are placed in what the builders felt was the most efficient location for walking traffic, especially in such a compact space.

“In Arlington, you’re not finding much under 4,000 feet. We did it consciously — we want to build sustainably,” he said, noting that the house was constructed under an Arlington County Special Use permit, in collaboration with the county itself as well as the surrounding neighbors.

The house, which also includes a back yard and rear patio, is on the market for $1.1 million.