Walls are just one of the many areas of the building envelope that can make a big difference in a building’s efficiency. Wall systems are used to wrap a building; systems hold different components like windows and doors, but also insulation, wiring and piping. Wall systems can act as structure or as a curtain.

There are several main ways that a wall can contribute to the environmental-friendliness of a property:Insulation and glazing of walls. Walls can be made from many different materials and can have many different types of insulation to maintain the optimal temperature inside a building. Walls that use thermal efficient panels can help virtually eliminate the transfer of temperature.

Other types of insulated walls are available to decrease drafts and dramatically lower heating and cooling bills. High-performance glazing, too, can help keep out the elements, balance moisture and maximize daylight.Green walls. These walls are, quite literally, green. The walls are constructed using a grid system to hold up plants. Other terms to describe these green walls include living walls, active walls or vertical garden. These walls do more than just provide a barrier—they act as an air filtration system. Intakes from the traditional HVAC collect air from the living wall, where the air must pass through soil, which filters it.

Living walls also can help filtrate greywater or rainwater for ruse. Green walls also absorb direct sunlight, cooling inside air and act as an insulator. They also help regulate humidity and provide a sound barrier. Green wall panels can made using polypropylene plastic containers or geotextiles. Most systems support a great diversity of plant species, including a mixture of groundcovers, ferns, low shrubs, perennial flowers and edible plants.

Living walls perform well in full sun, shade and interior applications, and can be used in both tropical and temperate locations.Sustainable walls. Walls that are considered sustainable are constructed from natural materials that are quickly renewable or can be easily recycled.

Some companies have focused in constructing walls that are insulated with straw bale compacted into wood and mesh frames. Others chose to use clay or mud to weatherproof walls; compressed soil and gravel are other popular materials for sustainable walls. Walls made with gypsum board scores extremely high on nearly all sustainable design criteria. Gypsum—the primary raw material used to make wallboard—forms naturally like salt or limestone, and it’s one of the most abundant minerals on the planet. The bulk of the remaining materials in gypsum board consist of paper (recycled from newspapers, phone books, old corrugated cartons and cardboard cuttings) and corn or wheat starch binders. Cement board—a water-durable, multiuse panel—is another sustainable alternative, and it’s commonly used as a backer for ceramic tile. It is made from approximately 20 percent recycled materials, including fly ash.

Fly ash is a waste stream material from power plant emission control processes that features cement-like properties and is used to manufacture the cement board panel core.