Energy-Efficient Lighting

Light affects our health, safety, comfort and productivity. You can start saving energy while maintaining good light and quantity.

Let's begin with Lighting Principles and Terms:

Lumen: a measurement of light output from a lamp, often called a tube or a bulb. All lamps are rated in lumens. Example: a 110-watt incandescent lamp produces about 1750 lumens.

Illumination: the distribution of light on a horizontal surface. Illumination is also measured in foot candles, which is a lumen of light distributed over a 1 square foot area.

    Since the amount of illumination varies according to the difficulty of a visual task, experts have divided lighting uses into three categories, ambient, task, and accent lighting.

Ambient: provides security and safety, as well as general illumination for performing daily activities.

Task Lighting: provides enough illumination so that tasks can be completed accurately but not to provide so much light that entire areas are illuminated.

Accent lighting: provides illumination to walls to blend more closely with naturally bright areas like ceilings and windows.

    There are four basic types of lighting: incandescent, fluorescent, high-intensity discharge, and low-pressure sodium.

Incandescent: is the most common type of lighting used in residences and are the least expensive to operate. Incandescent light is produced by a tiny coil of tungsten wire that glows when it is heated by an electrical current. These also have the shortest lives and are also inefficient  compared with other lighting types. There are three common types of incandescent lights: standard incandescent, tungsten halogen and reflector lamps.

                Standard incandescent: also known as the "A-type light bulb, are the most common yet, inefficient light source and is the oldest type of lamp.

                Tungsten halogen:  It has a gas filling and an inner coating that reflect heat. Together, the filling and coating recycle heat to keep the filament hot with less electricity. These are primarily used in commercial applications such as theaters, stores and outdoor lighting systems.

                Reflector lamps: These are designed to spread light over specific areas. They are used mainly indoor for stage/theater and store applications, and as well as floodlighting, spotlighting and down lighting.

Fluorescent: light produced by a fluorescent tube which is caused by an electric current conducted through mercury and inert gases. These are used mainly indoor, both for ambient  and task lighting. They last 10 times longer than a standard incandescent. Fluorescent lights need ballasts (devices that control the electricity used by the unit) for starting and circuit protection.