Lighting and Appliances

Light Pollution Reduction

The objective of reducing light pollution is to minimize the amount of artificial light that spills from our property to the neighbors’.  Having unwanted light falling from a neighboring home into one’s living spaces is annoying.  On a community scale, light pollution causes “sky glow” that creates a gauze of light that masks star light.  In urban areas the Milky Way is no longer visible.  We are able to see only the brightest stars and planets.

Pathway Lights – Patio Lights

To avoid light spill “night sky” or “zero cut-off” fixtures should be installed.  Most pathway lights are designed this way so the light shines on the ground where it is needed and not upward where it would cause light pollution.   Similarly designed zero cut-off fixtures can be installed for patio lights.  When choosing a fixture make sure it is labeled Zero Cut-off or Night Sky.

Security Lights

Security lights are most likely the greatest source of residential light pollution.  They are on motion detector switches and, for protection, illuminate large areas of your property when movement is detected.  Often the light spills outside property limits and can create a disturbance for neighbors and contribute to light pollution.  A number of things can be done to prevent light pollution:

• Security lights are on adjustable swivels and can be adjusted so the arc of light does not leave the property.
• Movement sensors can be adjusted so movement off the property does not turn on the security light.
• A light fixture with a shield can be purchased so all light is directed at the ground, eliminating upward light.

Interior Lights

The strategy here is simply one of designing the light arrangement so interior light does not spill out of windows.  The light source should be shaded (as most interior lights are) and the light itself should fall on opaque (non-window) surfaces.

Light Load Reduction

Reducing light pollution is an exercise in being a good neighbor.  Light load reduction is an exercise in saving money.  There are two ways to do this:

• Turn off lights when not in use (duh).
• Use energy saving light bulbs.

Turn Off Lights When Not in Use

The best way to do this is to physically turn off lights when you leave a room.  This proactive approach will make you a more energy conscience person.  If you can’t break the habit of leaving a room with the lights burning (it is said that it takes twenty to thirty positive repetitions to break a habit) you can install motion detectors that will turn the lights off after a period of non-movement.  The annoying problem with this system is that if you are in the room reading and still, the lights will turn off at the wrong time.  You can select rooms to install motion detectors, such as kitchens or bathrooms, where there is normally movement.

Use Low Energy Consuming Lights

There are three kinds of lights available:

• Incandescent bulbs and tubes
• Fluorescent bulbs and tubes
• LED (light emitting diodes) bulbs, sheets and tubes

Incandescent lights have been the standard for more than a hundred years.  The amount of energy they consume and their level of brightness are measured in watts.  We have come to associate the amount of energy a standard light bulb uses in watts with the bulb’s brightness.  So much so that compact fluorescent lights and LED’s are measured in equivalent watts so we can understand how bright they are. The actual energy consumed by a fluorescent or LED with the same brightness as a 60 watt incandescent is much less, hence, for the same level of brightness, there is a savings of electricity.  Furthermore, both fluorescent and LED lights last much longer than incandescent bulbs.  Fluorescent and LED lights cost more than standard incandescent bulbs, but since they last longer and use less electricity to run there is a pay back over the life of the bulb.

Conclusions

• Compact fluorescent lights (CFL) are much less expensive than incandescent bulbs over their life.
• LED lights are just coming to the market place.  As an inexpensive replacement for CFL’s they have just now evolved so the best prices make them more cost effective than CFL’s over their life.  With efficiencies of scale taking hold, LED’s are now the least expensive light source.

Benefits/Costs of LEDs

LED lamps have many advantages over traditional lighting methods.   These include:

• Low energy consumption – retrofit bulbs range from 0.83 to 80 Watts
• Long service life – LED bulbs can last up to 50,000 hours
• Durable – LED bulbs are resistant to thermal and vibration shocks and turn on instantly from -40C° to 185C°, making them ideal for applications subject to frequent on-off cycling, such as garages and basements
• Directional distribution of light – good for interior task lighting
• No infrared or ultraviolet radiation – excellent for outdoor use because UV light attracts bugs
• Safety and environmentally conscious – LEDs contain no mercury and remain cool to the touch
• Fully dimmable – LEDs do not change their color tint when dimmed unlike incandescent lamps that turn yellow
• No frequency interference – no ballast to interfere with radio and television signals
• Range of color – LEDs can be manufactured produce all colors of the spectrum without filters, they can also produce white light in a variety of color temperatures

There are some current disadvantages to LED lighting:

• LED are very heat sensitive. Excessive heat or inappropriate applications dramatically reduce both light output and lifespan
• LEDs typically cast light in one direction at a narrow angle compared to incandescent or fluorescent lamps so lenses or reflectors are needed in fixtures to broaden the beam (if desired)
• The “warm” LED’s that have the same color of incandescent bulbs, are about 2/3 as efficient as the “cool” LED’s
• There are few LED’s that are equivalent to 100 watt incandescent bulbs.  (See Evolux 13 watt lamp for about $50 plus shipping, which is comparable in brightness to a 100 watt incandescent bulb and as cost effective as a CFL)
• The little circuit boards that run the LED’s get warm.

The following table illustrates the differences between the three types of lights having equal brightness..

*Current list price of a Red Bird A19 bulb.

**Based on $0.1147 per kwh

Advantages of LED’s

• No mercury like compact fluorescents.
• LED’s are dimmable
• LED bulbs are cool to the touch
• LED’s last from 30,000 to 50,000 hours (if you turn on a light for 6 hours a day the lamp will last from 12 to 20 years)

Terms and definitions

Also see: http://www.edf.org/page.cfm?tagid=630

http://www.mediacollege.com/lighting/colour/colour-temperature.html

http://www.energysavers.gov/your_home/lighting_daylighting/index.cfm/mytopic=11990