It sure would be nice if there were a simple answer for everyone.
When do you cross the line from not enough lighting to too much? When do you go from not bright enough to too bright? We could honestly spend days trying to answer these two questions, but the science of vision plays an important part, as does personal preference; but we’ll try to give you some good ideas here.
First of all, a little light goes a LONG way. The human eye adjusts to darkness relatively quickly, so we often discover that our clients appreciate a lower light level than they originally anticipated. Think about this for a moment: the moon is 238,900 miles from the earth. Although we talk about how bright the moon is, in truth it doesn’t actually produce any light, it simply reflects the light from the sun. A full moon here in central Texas is bright enough for us to move around at night pretty comfortably, too. So, a reflective light source from almost 239,000 miles away produces a lot of perceived light. Moonlight often provides a guide when seeking the proper lumens for safe illumination.
I rarely use anything brighter than a 50 watt equivalent light source in my designs; and that will illuminate very large (tall) oak and pecan trees. Lighting smaller plants or structures rarely requires more than the light output of a 10 or 20 watt halogen equivalent light source to do a very good job.
The primary purpose of any good lighting design is to accent the landscape (and architecture), not turn your home yard into Disney Land. Commercial properties may require more light because of other ambient light sources in the area, or for required minimal foot candle illumination of walkways, but residential projects generally do not need nearly as much light. If you live on a 50’X100’ lot and you have 100 lights, I’m pretty sure you have too much. However, the number of individual fixtures may not be as critical in assessing over-brightness as the lumen output of each. This combination must be considered in the design and will be dependent upon the objects, focal points, and safety concerns on the property.
If you get any complaints from a single neighbor about the brightness of your lighting, it could very well be a bit too much; or it may be improperly aimed or installed. If your lighting is shining onto your neighbor’s property, this is called “light trespass” and it needs to be adjusted. Step back and pretend to be your neighbor. If you think that you may have a little too much lighting, then you probably do.
Remember, less is more and it’s better to use lower lumen levels when designing an outdoor lighting system. Your eyes will adjust and your neighbors will happy.
NightScenes is a member of the International Dark Sky Association . We believe that any property can be illuminated well and still help protect our night skies from light pollution. We would love to help you asses your outdoor lighting needs in a responsible manner. Contact us here to set up an appointment.
