Brightness

The amount of light that a light fixture or light bulb emits is measured in lumens. Today’s bulb packages all reference this measurement. Remember: A fully shielded light fixture — one that directs all of its light downward, below horizontal — will require fewer lumens than an unshielded one to make the same impact on the ground. It also creates far less glare as well.

After you locate warm-hued bulbs (which have a low color temperature), DarkSky Mass member and lighting designer Glenn Heinmiller has some recommendations as to how many lumens you actually need:

“Start low, with the lowest lumens fixture or light bulb, and then add more if you need to. It will probably be enough. Start with 200 to 400 lumens for general residential outdoor lighting, and go up to 800 lumens if you really need it. A fixture with thousands of lumens is way too much for residential lighting.”

He further comments, “More light is not better. Higher light levels don’t mean that you can see better. They don’t make it safer than anything once you reach a certain threshold. And that threshold is generally probably a lot lower than people realize now.”

Use the following recommendations as guidelines for how many lumens you’ll need for specific outdoor-lighting applications (click here for fuller explanations):

  • Step lights: 12-100 lumens
  • Hardscape lights (on walls): 50-185 lumens
  • Landscape lights: 50-300 lumens 
  • Path lights: 100-200 lumens
  • Landscape spotlights: 120 lumens
  • Lamp posts: 120-180 lumens
  • Pond/pool lights: 200-400 lumens
  • Motion sensor lights: 300-700 lumens
  • Flood lights: 700-1300 lumens

Whenever you replace or install outdoor lighting, remember these Five Principles for Responsible Outdoor Lighting:

  • All lighting should have a clear purpose
  • Light should be directed only where needed
  • Light should be no brighter than necessary 
  • Light should be used only where it’s useful
  • Lights should have a warm color temperature wherever possible

This graphic shows the main aspects of the Five Principles of Responsible Outdoor Lighting. Brightness is addressed in the “Intensity” panel.

(image credit: Observatoire du Mont Mégantic, Québec, Canada)