As the LED lighting market continues to develop, it has already affected the way we do new construction lighting design.
LED lighting is typically more efficient than other types of lighting and has become the “go to” solution to meet the energy code lighting wattage budget. But even as prices of LED lighting come down to more affordable levels, it is still more costly than more traditional types of lighting. For cost reasons, we typically don’t automatically do a 100% LED lighting design (although the energy code may drive that decision eventually).
Let’s look at dimming lighting as an example of the way things are changing. Incandescent lamps can be dimmed from 100% down to 0% and is the model for dimming. But incandescent lighting uses more wattage than any other type of lighting. In order to have sufficient light levels throughout a building, and also meet the energy budget, incandescent light fixtures have to be eliminated or restricted to just a few decorative light fixtures.
This leaves high intensity discharge (HID) dimming, fluorescent dimming, and LED dimming as options. HID dimming has special problems with control and color shift and is rapidly fading as a popular dimming solution. Fluorescent dimming and LED dimming are still viable solutions when reduction of light levels is required.
LED and fluorescent dimming can perform comparably. We are finding that LED dimming fixtures cost 5-10% more than equivalent fluorescent. LED dimming fixture wattages are usually lower than fluorescent dimming, but not by much. Where LED and fluorescent dimming fixtures differ is in the maintenance. Fluorescent lamps must be ‘seasoned’ or “burned in’ before they are dimmed. If fluorescent lamps are not properly seasoned before dimming, the lamp may have a drastically shorter life. LED dimming sources do not have this issue. They also have longer rated lives – sometimes 10 times the life of similar fluorescents. (Caveat: rated life of LED sources is different from other types of light sources. It is a projection based on data obtained by IES guidelines. LED sources are not really tested to end of life. They could be obsolete before they fail.) LED sources have a different set of problems –they don’t like heat. The fixture designed for an LED light source has to get the heat away from the LED or risk premature failure.