Designing with LEDs

Can I replace one Mercury Vapor tree light with one LED light and have the same results?

Not exactly. A 100W MV light is 3000+ lumens with a 100° beam spread. For an LED light to compete in lumens, the beam spread must be reduced to anywhere from 25° to 40°; anything wider than that will result in much less measurable light on the ground. Therefore, to achieve the desired .1 fc on the ground from a moonlight downlight 40’ up in a tree, we recommend a ratio of about 3 LEDs to 2 MVs. For the best moonlight effect, add a “mercury vapor green” and diffused lens to the lamp. This softens the light and spreads it out creating beautiful moon beams of light.

Consider the example below:

Shown with (4) 100W MV Downlights

Shown with (7) 14W LED Downlights

These pictures were taken of a house with downlights mounted 40’ high in mature red oak trees. You can see the difference in spread between the two scenarios. The Mercury Vapor scene on the left illuminates the roof of the house as well as the entire yard with just four fixtures. The LED scene on the right still has amazing light coverage on the ground, yet the spill-over light on the roof is gone.

LED Lights: Warm White vs. Cool White

Typically, Cool White (5000K) LEDs are used to illuminate in the landscape on trees, bushes, etc. The eye is used to seeing the cool moonlight hues coming through the trees at night, creating a very natural and serene setting. Cool White light enhances the color of foliage, making trees and vegetation look even greener and healthier. Use Warm White (3500K) LEDs to light the house, fence, or other structures such as gazebos, arbors, or fountains. Warm White light brings out the texture of a surface and creates crisp and inviting light in seating or dining areas.

Comparable Wattages in LED

When working with LEDs, a little bit of light can go a long way. A 4W lamp may not sound like much, but it is equivalent to a 20W halogen. We typically use 4W lamps on small ornamental trees and illuminating the front of a one-story home. For medium trees or a two-story home, you may want to upgrade to a 5W (35W halogen equivalent) or a 7W (50W halogen equivalent). By nature of their design, a cool white lamp (5000K) will always be brighter than a warm white (3000K) – even if the wattage is the same. For tree lighting,

Tree Lighting with LED Lights

Downlighting in trees is the preferred way to achieve the true moonlight effect. The best design advice we were ever given regarding tree lighting was from Lloyd Reeder of Greenlee Lighting. He always said “Mount as high in the tree as you can—then go 10’ higher and it’s perfect!” Always position the long shields so that the lamp is not visible from the ground to avoid glare. Do not place fixtures too close together, but instead spread fixtures out in the canopy. Aiming straight down from the top of a tall tree gives soft subtle shadows and moonlight patterns on the ground. Be sure to catch as much foliage through the trees as possible to get the best shadows.

When uplighting trees, be wary of fixture placement regarding tree roots, landscapers, and vandals. It’s very important not to aim fixtures past a 90° vertical to ensure water will not collect in back of shield. The fixtures have convex lenses and should tilt forward to allow water runoff. Using 2 uplights on either side of the trunk will add depth and texture. Mount uplights at least 3 feet from the tree trunk to avoid a hot spot at the base. Be sure to use a sturdy stake mount, such as the LGS, to ensure the fixture will not lean or move over time. It’s always a good idea to check on your uplights every now and then to make sure they haven’t shifted since their original installation due to landscapers or vandals.

Moon Visions Lighting is our preferred vendor for tree lighting.

Best Moonlight effect with LEDs

By adding the Mercury Vapor (MV) green lens to the 5000K Moon Visions’ brand of LEDs will create the closest simulation to moonlight there is an LED lamp. Add the Overall Spread Lens (OSL) or Diffused lens (DIF) to widen the beam spread from 40° to almost 80° or soften the light. Fabricated lens clips are required for the 22W PAR38 and 14W PAR30 only, but the lower wattages are glued on with a special weather-resistant epoxy. Each will hold up to two lenses at a time. These lenses add a custom look you can not achieve with other commercial-type, mass produced LEDs and are exclusive to Moon Visions Lighting.