Landfill

A waste disposal site for the deposit of solid waste from human activities.

Land stewardship

The act of managing the land and its resources in a sustainable or restorative manner.

Latent heat

The heat required to change the phase (i.e. a liquid to a gas) of a material without altering its temperature.

Latent load

Cooling load resulting from thermal energy released when moisture in the air goes from a vapor to a liquid state. In hot humid climates, cooling equipment must have sufficient capacity to handle this load if occupants are to be comfortable.

LCA

Life cycle assessment: a process to evaluate all costs of a product or process through its entire existence, including extracting and processing of raw materials, manufacturing, transportation, distribution, use, maintenance, recycling, reuse, and disposal.

LCC

Life-cycle cost: the costs accruing throughout the service life of a material. Life-cycle costs address the capital costs involved in production, maintenance, and disposal, and can also include other environmentally related capital costs and societal costs.

LCI

Life cycle inventory: an accounting of the energy and waste associated with the creation of a new product through use and disposal.

Leachate

Water that collects contaminants as it trickles through wastes, pesticides or fertilizers. Leaching may occur in farming areas, feedlots, and landfills, and may result in hazardous substances entering surface water, ground water, or soil.

Lead (Pb)

A harmful environmental pollutant that is typically in the home in lead-based paints before 1978, and in lead solder used in plumbing. Lead is toxic to many organs and can cause serious damage to the brain, kidneys and nervous system.

LED

Light-emitting diode: a revolutionary illumination technology using chips in lieu of bulbs. These emit less heat, are long-lasting, are easily dimmable and programmable, and have more color choices. They use approximately 40% less power than a compact fluorescent bulb (CFL) with the same light output. Currently, some wide-spread applications of LEDs are exit signs, holiday light strings, and traffic signals.

LEEDTM

Leadership in Energy and Environmental Design: created by the US Green Building Council (see USGBC), LEED is a green building, points-based rating system used as a standard for developing high performance, sustainable buildings. The LEED system is a voluntary, consensus-based national standard for new commercial construction (NC), commercial interiors (CI), core and shell (CS), homes (H), neighborhood development (ND), and existing buildings (EB) with more categories under development. The ratings are: Certified (26-32 points), Silver (33-38 points), Gold (39-51 points) and Platinum (52-69 points). Professionals can become a LEED Accredited Professional (LEED AP).

Leichtlehm

(See Light clay).

Life-cycle

The consecutive, interlinked stages of a product, beginning with raw materials acquisition and manufacture and continuing with its fabrication, manufacture, construction and use, and concluding with a variety of recovery, recycling, or waste management options.

Light

Visually perceived radiant energy (a small part of the electromagnetic spectrum).

Light clay

Straw and clay mixture moistened and pressed between forms, which hardens into a strong, insulating material. An old and durable technique, it is typically used for making walls. Also known as leichtlehm (German for light loam). 

Light construction

Construction of a building using materials which have low densities (like wood or aerated concrete). The lower densities of these materials reduce their capacity to store heat.

Lighting power density

LPD is the maximum allowable lighting density permitted by the code. It is expressed in watts per square foot for a given occupancy/space type.

Light pollution

Unwanted light in the night sky, as from city lights, that makes it more difficult for astronomers to see and photograph celestial objects.

Light shelf

A daylighting strategy that allows natural light to bounce off a shelf located in a window and onto the ceiling to bring light deep into a space.

Linoleum

A durable, natural flooring and countertop material made primarily of cork flour, linseed oil, oak dust, and jute. Linoleum has durability, renewable inputs, anti-static properties, and an easy-to-clean surface.

Living building

A building that actually produces more energy than it consumes, restores habitat and cleans water in its operations. The Cascadia Chapter of the US Green Building Council (USGBC) issued a Living building Challenge in 2006 outlining specific building performance characteristics.

Living roof

(See ecoroof).

Locally-sourced materials

Materials obtained from a defined radius around a project site, helping to support the local economy and reducing transportation costs and energy.

Louvers

A series of baffles used to shield a light source from view at certain angles, or to absorb unwanted light, or to allow selective ventilation.

Low-emissivity (low “e”) windows

Glazing/glass that has special coatings to permit most of the sun’s visible light radiation to enter the building, but prevents heat loss from the interior to the exterior. 

Low-flow/flush commode

A toilet that uses 1.6 gallons of water/flush, instead of 3.5 gallons/flush. This plumbing code standard was adopted in 1992. As of 2007, the Environmental Protection Agency (EPA) has set a voluntary 20% efficiency reduction to 1.28 gallons/flush (see Dual-flush commode).

Low-flow shower head

A water saving shower head typically rated at 2.5 gallons per minute (gpm) or less. These shower heads can be aerating (introducing air into the water flow), or not.

LSG

Light-to-solar-gain ratio: a measure of the ability of a glazing to provide light without excessive solar heat gain. It is the ratio between the visible transmittance of a glazing and its solar heat gain coefficient.

Lumens

Amount of light given off by a light source.