LEDs Can Dramatically Light a Typical Home Now

Posted: December 2, 2008 in General SSL Commentary
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This stair and hall are lighted with generic PAR20 and PAR30 LED retrofit lamps. The total energy consumed for the space shown is 36 watts.

Entry Hall and Stair

The only way to benchmark the good and the bad of LED lighting in typical home environments is to put them in place and live with them. These images show that even current LED devices can work, producing attractive, if not dramatics effects, and some energy saving . This is a summary of one test project.

The original lighting in the main stair and entry hall included (3) 50PAR20 NFL lamps and (3) 75PAR30 NFL lamps, mounted in track heads. These were dimmed to roughly 30% of full light output, and were measured to consume a total of 265 watts. The LED retrofit lamps are operated at 100%, since no suitable dimmers have been found to control them. The LED products consume a total of 36 watts. This represents and energy savings of 86% over the halogen lamps replaced. The cost of the LED lamps was $164. With an annual energy cost saving of $18, payback is over 10 years. However, with no loss of color and quality, the contribution of saving in energy demand and reduction in polution is worth the cost.

The light within the space is similar to the original PAR lamp illumination, including the side light. Brightness is also roughly the same when viewing the lamps themselves.

Living Room

Living Room

The living room was originally lighted with 9 20W MR16 lamps, including sculpture lamps in the right hand corner. Dimmers trimmed light levels to roughly 25% of full light putput. Replacing all of the MR16’s with 4 watt LEDs did reduce total light levels, but restulted in just 36 watts consumed, a saving of 54 watts for this space.

In the recreation

Entertainment Room

Entertainment Room

room, the original lighting included 5 20W MR16’s on a rail system, 3 20W MR16’s in a corner sculpture, and 2 50PAR30FL lamps in recessed accent lights. These are operated from dimmers at very low levels, for a total of 78 watts. All of the MR16’s were replaced with retrofit lamps, and the PAR30’s were replaced with Tri-Star color-changing lamps with remote controls.

Kitchen

Kitchen

The kitchen was originally lighted with 75R30 incandescent lamps operated on dimmers. These were replaced with Cree LR6 LED retrofit inserts, also operated on dimmers. This reduced energy use from a maximum of 300 watts to 48 watts, for a saving of 84%. Light levels are lower on the island counter surface, but higher into the cabinets and onto the perimeter counter tops. The retrofit LED products perform very well, the color is pleasant. In addition, GE under-cabinet LED strips have been added to provide counter top light in the evenings, using only 6 total watts. This overcomes the

Mud Room Hall

Mud Room Hall

shortcoming of the 20% minimum dim level of the Cree downlights well.

The back mud-room hall uses just 2 PAR20 LED lamps in place of the original 50PAR20 NFL lamps on dimmers, for a saving of a few watts.

Problems so far: For the most part, everything has worked very well. Living with the LEDs has been very easy, and the dramatic lighting effects originally designed into the lighting system have been maintained. However, dimming has been a struggle. Other than the kitchen, we have not found a solution to the poor dimming characteristic of the retrofit lamps, so operate them at full power.

There have been 2 premature failures. We found that even when low end dimmers are set at 100%, they generate a low output voltage (105 volts measured). The two lamps that failed were operating under this condition.

There has also been a problem with low voltage transformers not operating properly under the reduced load of the retrofit MR16s. The minimum load required seems to be no less than 5 watts for the electronic transformers we have in the home. Further, we have found that magnetic transformers designed for 20 to 50 watt loads, draw 26 watts when driving a 4W LED MR16. These were replaced with new transformers more suited to the load connected.

Recommendation rating = 7 of 10. If you are truly interested in solid-state lighting, I recommend making an effort to apply them where you can, and live with them. The lessons learned are pplicable to design work on other projects. From this ongoing experience, we are finding the best approach is to test everything, and not take anyones word for performance or sutiability.  The amount of energy saved in this application has appeared in reduced electrical bills, so we do know that the savings are real. As the technology improves, these products will be upgrades as an ongoing lab test work-in-process.

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