Outdoor Lighting and the Dark Sky
By Larry Bartlett
Governer John Lynch has established a New Hampshire "Dark Skies" policy by signing legislation on July 15th
2009. The bill (HB 585) dictates to municipalities regulations that limit the output and duration of public
lighting. It is an initiative that has moved to the center of the political arena because of the efforts of the
"dark sky movement."
What is "dark sky?" The dark-sky movement is a campaign organized by people who want to reduce
light pollution so that people can see the stars, reduce the effects of unnatural lighting on the
environment, and to cut down on energy usage. The movement has since spread with groups like the International
Dark-Sky Association as other concerns have been raised. For example, nocturnal animals can be disoriented by
light pollution. Light that accidentally crosses a boundary and annoys a neighbor is generally considered
wasted and intrusive light.
At this point, the law pertains only to public utilities, however local communities are "encouraged" to enact
similar regulations with regard to building codes and town laws. While this movement is still in the "encouraging"
stage with regards to private property, homeowners should be aware of the "intrusive light" that crosses over their
So what does this have to do with me? It is said that "good fences make good neighbors." Can we
take that a step further and say, "soft lighting also makes good neighbors?" Whether you agree with the dark sky
movement or not, it is prudent to recognize that glaring outdoor lighting can become a problem for you as a
homeowner as this movement gains popularity.
As a landscape lighting designer, I am always zealous to eliminate glare. In outdoor lighting design you should
always see the light, but not the source of the light. To most people, outdoor lighting involves a
spotlight over the garage, lamp posts, or fixtures on either side of the front door. All of these light sources
produce glare. Security lighting may spread a bright light on the driveway, but you need to remember that the
brighter the light, the darker the shadow. Glare creates dark shadows that can hide intruders and create a safety
issue especially for the elderly.
Light that accidentally crosses a boundary and annoys a neighbor is generally considered wasted and
Ambient Light - The solution is ambient light. Think of taking the 240 watts that is coming from two
spotlights over your garage and spreading them out with ten 20 watt fixtures. You can expand the coverage area and
direct the light exactly where you want it. Low voltage lighting can be operated with a timer and photocell, and is
less expensive to run than 120 volt fixtures.
Beam Control - The maximum wattage of a low voltage landscape lighting fixture is 50 watts, and
most often 35 watts is sufficient for up lighting. MR-16 lamps, which are the workhorse of landscape lighting
bulbs, allow for specific beam control because they come in a variety of degrees and wattages. You can spread the light on the ground
with path lights. Spotlights come with shrouds and filters. Trees that are up lighted reflect light back
onto the ground which often times is sufficient for visibility in low traffic areas.
Beauty - Probably the greatest advantage to low voltage landscape lighting is
the dramatic effect on the structural elements in your yard. A tree or an object that is overlooked during the day
becomes alive at night. Up lighting reverses daylight, creating an opposite texture of what you see during daytime.
Even if you're not outdoors at night, ambient landscape lighting removes the "black mirror" that is your normal
night view from inside the house.
Don't be surprised if you notice your neighbors admiring your yard at night. Maybe you don't want the attention,
but it sure beats the alternative!