Renewable energy: Energy from resources that are regenerative or for all practical purposes cannot be depleted, such as moving water, biomass, geothermal energy, solar energy and wind energy.

Reuse: Using an item more than once, often by repairing, donating or selling the item.

R-value: A measure of the ability of a material to resist the transfer of heat. The larger the R-value of a material, the greater the insulating properties.

Solar energy: Electromagnetic energy transmitted from the sun. The amount that reaches the earth is equal to one-billionth of total solar energy generated.

Source reduction: Waste prevention, or consuming and throwing away less by purchasing durable, long-lasting goods, seeking products and packaging that are as free of toxics as possible, and redesigning products to use less raw material in production, have a longer life, or be used again after its original use. Reuse is part of source reduction.

Tankless water heater: A water heater that heats water before it is directly distributed for end use as required or on demand.

Triple pane (window): A window with three layers of glazing, with airspace separating the middle glass from both the exterior and interior panes.

Volt: A unit of electrical force, it equals the amount of electromotive force to cause a steady current of 1 ampere to flow through a resistance of 1 ohm.

Voltage: The amount of electromotive force, measured in volts that exists between two points.

Watt: The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or 1 joule per second.

Watt-hour: A unit of electricity consumption of 1 watt over the period of 1 hour.

Wattmeter: A device for measuring power consumption.

Wind turbine: A term used for a wind energy conversion device that produces electricity; typically having one, two or three blades.