One of the newest technologies in lighting is LED (light-emitting diode). But is it that easy to find, specify and place? What about the cost? In our recent experience with clients looking to update their community lighting—both decorative and functional—switching to LED was easy to achieve in some areas, but a challenge for others. We researched the retrofit of a variety of LED sources for common areas, private rooms and in staff spaces. Our findings were not what we expected.
Although LED lighting has been around since the 1960s, only in the last few years have we started to address its use in commercial buildings. While LED lighting serves a purpose in senior living environments, the selection and location of LED fixtures should be heavily considered and researched so that reliable and cost-effective products are selected.
LED—JUST WHAT IS IT?
LED is a semiconductor light source. When an LED is switched on, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This process creates light-emitting photons, or what is known as electroluminescence. But there is a lot of light buildup in this process, which has been an obstacle for LED creators. Some say LEDs are a “temporary” solution to energy-efficient lighting because they have a narrow focused light beam and cost more.
A modern retrofit LED lamp with "bulb" shape.
LEDs have many advantages over incandescent light sources, including lower energy consumption, because there is less wattage for lumen output, longer lifetime (life span of 35,000–50,000 hours, improved physical robustness, smaller size and faster switching.1 In addition, LED lighting can be used for “light harvesting,” controlling the amount of light needed based on how much natural light is penetrating the space and they can be dimmed. A dimmable ballast for a CFL costs run about $75–$100, but with LED, the dimming is free!
One of the most common misunderstandings about LED lighting is that energy consumption can be used to measure light output. Unlike conventional incandescent bulbs, in which the light output is relative to energy consumed, an LED’s light output is measured in lumens regardless of energy consumption.
LED lights can consume a variable amount of energy, however any given LED system will have, depending on whether phosphor has been used to coat the diodes (and the amount), an optimal lumens/watt output that maximizes the life span of that particular LED system. The life span of the LED system also depends on the thermal management properties employed by the manufacturer.
Another misunderstanding of LED lighting is that there is a limited color temperature. The application of phosphor coating to a diode will give a warmer color temperature. The more phosphor applied to a diode, the warmer the color temperature of the LED.
ENERGY CODES, LIGHT LEVELS AND THE AGING EYE
Inadequate lighting, a safety concern because it affects depth perception, is often one of the main reasons a resident does not want to venture down a hall or leave his/her room. But adding more light does not necessarily mean it is better light and the source of that light needs to be considered for placement, glare and optimal use of a space.
What are the best foot-candles needed for senior living and how can we meet the required light levels by using the allowable wattage restrictions? Lighting and energy codes do not often reflect the real needs of our elders. Older eyes need 75 percent more light than those of a 25-year-old because the lens of the eye becomes more transparent.
The eyes of an older adult become more sensitive to glare. The pupil becomes smaller and less responsive to variations in light. The lens of the eye begins to lose elasticity, which leads to loss of focusing power or lens accommodation known as presbyopia. On top of that, the lens of the eye will gradually yellow with age, making it difficult to see differences in colors like blue, blue-green and violet. Bulbs with a color rendering index, or CRI, of 80 will improve sight because of improved color rendering.
Resident lighting needs for a specific use or activity should take into consideration the amount of light needed for the activity, the needs for adjustability and color temperature. A good rule of thumb is 2900–3500K (Kelvin) for senior living environments. These same color temperatures are available in LED lighting.