Landscape Architect Articles

''It‚Äö?Ñ????ë?¬•s Just Another New Light Source...''04-29-11 | News

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by Jan Moyer, IALD, Jan Moyer Design, LLC, LASN Associate Editor for Lighting

We can light trees with many different light sources?EUR??,,????'?????<

It is not the first time. Back in the 1980s a GE engineer suggested the architectural world start using MR16 lamps. At first there were no fixtures for them. There were only a couple wattages and beam spreads, and they cost about $20 each. It seemed outrageous. It didn?EUR??,,????'?????<

It is not the first time. Back in the 1980s a GE engineer suggested the architectural world start using MR16 lamps.

At first there were no fixtures for them. There were only a couple wattages and beam spreads, and they cost about $20 each. It seemed outrageous. It didn?EUR??,,????'?????<

We?EUR??,,????'?????<

This is the LED lit tree. Just as with other sources we use to light trees, this lighting required multiple fixtures, a combination of 15 up and down lights (3 to 8 watts) on one 360-watt transformer to create the three dimensional shape. Note the care taken to light the trunk and the overall shape of the canopy.

The LED Revolution
Changes in LED development continue at breakneck speed. Every day I get calls and emails about new products. One that just caught my attention was an MR16 LED replacement lamp, available in multiple color temperatures, multiple beam spreads and suitable for an enclosed fixture. I emailed the manufacturer (Array) to make sure these could really be used in completely enclosed landscape lighting fixtures. Yes. They offer two wattages. One has a flood distribution of 60???????(R)? - 100???????(R)?. Not sure what that means, exactly. I also asked what they cost and they directed me to their New York representative. After calling them I expected to receive a list with prices the following week. It is now almost a month later and I have not gotten any pricing.

Some landscape lighting fixture manufacturers suggest specifiers ?EUR??,,????'?????<

Do we need to understand all the instruments and gizmos on an aircraft before we take to the air? No, but when it comes to lighting, I still have a hard time with that approach. The reason I wrote The Landscape Lighting Book in 1988 was to understand materials, finishes and corrosion enough to evaluate a fixture and know for certain it would hold up in the outdoor environment. When I was done researching materials, finishes and corrosion, I had unearthed from the UC Berkeley Chemistry Library 13 kinds of corrosion we need to deal with in landscape lighting. Only eight types made it into the book. The editor told me to cut 40 percent of the first draft (see pages 143-145 of the second edition).

What I want you to think about, however, is that LEDs are just one of the light sources available to us. I don?EUR??,,????'?????<

When you look at the efficiency of a fluorescent fixture, you take into account the amount of energy required to operate the ballast. We need to be aware of the other energy considerations in a fixture configuration with an LED lamp, because the driver uses energy.

Figure 7: This drawing shows the combination of Halogen MR16 downlighting and LED uplighting. The uplighting consists of three different wattages and three beamspreads. The fixtures are replaceable module type units. As with any light source, it takes multiple fixtures to show the beauty of a tree?EUR??,,????'?????<

Lamp Considerations
Many considerations determine lamp selection:

1) Can it produce the lighting effect we want? I have not used a lot of LEDs, but each time I have I?EUR??,,????'?????<

2) Can we dim it? With the early LED fixtures I have used in landscape lighting projects, it has been on/off only. I think we are making progress on the dimming front, yet just recently one of the major dimming equipment manufacturers was still trying to sort out which LED sources worked with which of their dimming products.

3) What?EUR??,,????'?????<

This Japanese maple, which sits just outside the Jan Moyer Design studio, was planted about six years ago. I originally had two GE 37-watt, 24???????(R)? halogen MR16 lights mounted at the eaves to downlight it (Figure 1, Top). As with many maples, the downlighting just highlighted the outside of the canopy. That lighting sufficed until 2010, by which time the tree had substantially grown. Figure 2 (bottom): I added LED uplighting: two SPJ 5-watt, 45???????(R)?, 2750???????(R)?K; one SPJ 3-watt, 80???????(R)?, 2750???????(R)?K; and two HK Lighting 2-watt, 120???????(R)?, 3000???????(R)?K. The new LED uplighting now shows the trunk and branching structure and fills in the lower portions of the canopy. Note the shadows on the adjacent studio wall.

UL and Light Output Testing
Something else I?EUR??,,????'?????<

The light output was based on the lamp. Now, with LED sources, the fixture manufacturers continue to have to send their fixtures to UL for testing, but also have to have photometric testing done on each wattage, each color temperature and each beam spread. The massive amount of additional testing, while absolutely imperative for specifiers to know what we?EUR??,,????'?????<

This image shows mock uplighting for a rain wall being constructed. It consists of one-watt and two-watt LED units. These were the only fixtures small enough to recess into the stone of the rain wall, and with soft enough lighting to not overwhelm the wall. The lighting comes from multiple locations to show the form and texturing of the stone and the planting.

A New Light Source to Our Toolbox
I like to think we are adding a new light source to our toolbox. To convince some of our clients to use them, however, we need to consider the cost. Philips has its Endura LED interior retrofit lamp on the shelves at Home Depot for $39.97. Two years ago they were planning to make one of the first available in Europe at $107 each.

That is a big cost drop, but still significantly more than a homeowner is used to paying for a replacement light bulb for the table lamp. Market predictors suggest demand is going to be way up in 2011 and prices significantly drop.

That could be good for the LED market. What it will do to other lamp costs? Will fluorescent and MR16 halogen lamps become more expensive?

This backyard has a mix of light sources, but the two trees and step lighting are LEDs. The halogen path lights and the LED tree uplighting blend 3-watt, 80???????(R)? beam and 7-watt, 45???????(R)? beam spreads. Both trees have multiple fixtures. The olive tree has six fixtures but will need more as the tree grows. (Specifiers need to plan for tree growth when uplighting, downlighting, or attaching fixtures to trees.) The Tibouchina has four uplights and one downlight for the stairs.

Platforms
Another issue I?EUR??,,????'?????<

Some think this may be the year we start to settle on a standard. That would help cost come down. Some don?EUR??,,????'?????<

With our other lamps, we have ANSI standards for beam spreads. With LED equipment, the beam spreads of manufacturers are all over the map. We used to have a reliable spot (9 to 15 degrees); a medium flood (24 to 28 degrees); a flood in the 36 to 40 degree range; and a wide flood at 60 degrees. One manufacturer today has a spot at 17.7 degrees and a medium flood at 22 degrees. Will there really be a useable difference between these?

Many fixture manufacturers offer a wide flood between 80 and 120 degrees. A beam spread that wide will be very difficult to shield without cutting out a significant portion of the light output. Some of the wide spreads that I have tried seem to have a noticeable spot in the middle and the field light does not seem to do much.

Two 20-watt 4000???????(R)?K LED lamps with an integral, replaceable module were used in these fixtures to light this entire scene. It comes on each night and stays on for several hours. It has been operational since November 2009.

Coming Innovations
I recently had a meeting with an LED chip manufacturer who asked me to think about the amazing advances in personal computers. They, of course, continue to evolve. His vision is there are still many innovations and inventions to come in lighting. There will be several platforms to choose from, not surprising considering all the types of incandescent, fluorescent and HID sources. Why wouldn?EUR??,,????'?????<

He cautioned our industry to think about the parts that go into the package that makes up an LED light source. The LED chip is one part. It needs multiple components to make a light source. One or more of those parts will potentially fail before the LED. The drivers have life warrantees significantly shorter than the LED. He was also suggesting that on some types of LED sources, like the walk/don?EUR??,,????'?????<
Environmental Factors
My last thought is what happens to a fixture with an LED source in a snow storm? I recently moved east to New York. This winter we have experienced a record amount of snowfall and snow build-up on the ground Last winter a friend of mine asked if an LED uplight would become unusable during the winter. I did not know, but this winter has been a good testing ground. The Japanese maple outside my studio door for years was small enough that we could simply downlight it from the eaves. This year it got large enough to need uplighting. We added five LED uplights: two 5-watt, 45 degree spread; one 3-watt, 80 degree spread, and two 2-watt, 120 degree spread (see Figures 1 & 2, p. 38). What we learned is that it takes about one day longer than a halogen MR16 (any wattage) for an LED to burn through the snow and remain functional, as long as it is essentially aimed up. If it is aimed sideways, as was one of our fixtures on the maple, then it takes a couple days longer.