A kitchen without adequate task lighting will be very difficult to cook in. Likewise, proper lighting in a bathroom can ease shaving or applying makeup. Much has changed in the design and execution of lighting in our important living spaces, so below are excerpts from NARI’s newly revised CKBR Study Guide regarding the topic of lighting.
LED stands for light-emitting diode. They produce light 90 percent more efficiently than incandescent bulbs. How do they work? An electrical current passes through a microchip to illuminate the tiny light sources we call LEDs. To prevent performance issues, excess heat is absorbed into a heat sink.
LEDs are incorporated into bulbs and fixtures for general lighting applications. Small in size, they provide unique design opportunities. Some LED lamps may resemble familiar light bulbs to better match the appearance of traditional bulbs. Some LED light fixtures have LEDs built in permanently. LEDs offer tremendous opportunity for innovation, and they fit a wider breadth of applications.
LEDs are directional light sources, which mean they emit light in a specific direction, unlike incandescent and CFL (compact fluorescent) lights, which emit light and heat in all directions. Thus LEDs are able to use light and energy more efficiently in a multitude of applications. It also means that sophisticated engineering is needed to produce an LED lamp that shines light in every direction.
The small sizes of LEDs make them very versatile. The most common types are:
- Bulbs. A standard LED bulb is designed to screw into a conventional socket.
- Pucks. Small, surface-mounted LED lights typically used in cabinets.
- Tape lighting. LEDs applied to a ream of tape. The tape can be applied directly to a finished surface or concealed inside a diffuser. They are typically used for accent lighting inside architectural features.
- Bar lights. Pre-assembled tape lighting inside a diffuser for easy installation.
- Recessed. Pre-assembled LEDs with housing for a recessed fixture.
- Wafer. Surface- or flush-mounted LEDs designed to replace recessed fixtures.
- LED luminaires. LEDs are now being built into the finished luminaires.
Lamps emit light that is measured in lumens. The lumen output of a lamp depends on the lamp type and its wattage. For the same lamp type, the lower the wattage, the lower the lumens emitted by the lamp.
The color characteristics of lamps are measured in two ways: correlated color temperature (CCT), measured in degrees Kelvin, and color rendering index (CRI).
CCT is a measure of the color of the illumination produced by the lamp in terms of its warmth or coolness. A low color temperature (3000K and lower) describes a warm source, and the illumination appears yellowish-white, such as a typical incandescent lamp. A high-color temperature (4000K and higher) describes a cool source, and the light appears bluish-white.
CRI is a technique for describing the effect of a light source on the color appearance of objects being illuminated, with a CRI of 100 being the maximum CRI possible. In general, a lower CRI indicates that some colors may appear unnatural when illuminated by the lamp. CRIs of two or more lamps should only be compared if the lamps have the same correlated color temperature. CRI characterizes how well the illumination produced by the lamp makes objects appear natural. Remember, both CRI and light level affect color rendering.
Keep these tips in mind for your projects:
- Lamp types: For good color in residences, request lamps with a CCT of 2700 to 3500 K and a CRI of at least 80 or above.
- Standardize: When mixing lamps, use ones with the same CCT rating.
- Ambient light: Provide ambient light throughout all rooms to eliminate dark areas and allow for good visibility. Keep brightness in adjacent spaces similar.
- Older residents: A typical 65-year-old needs 10 to 15 times more light than a teenager to experience equal visual acuity.
- Room colors: Use light colors on walls, ceilings and floors to increase diffuse, inter-reflected light in the living environment. This will reduce glare.
- Consider reflectivity: The amount of perceived light from under-cabinet, accent and cove lighting will vary greatly depending on the reflectance value of surrounding surfaces. A dark countertop and backsplash will absorb light from under-cabinet fixtures. Likewise, indirectly illuminating a dark, wood-paneled ceiling is much less dramatic than illuminating a white ceiling. Increased illumination can offset light absorption on dark surfaces.
- Tasks: Identify where tasks will be performed and use extra light in those places. Examples are make-up application or food prep.
- Adjustable: Use switches and dimmers to let people adjust light levels for tasks.
- Natural light: Use daylight through windows and skylights to increase light levels and improve color discrimination. Use blinds, shades or curtains to reduce glare.
- Positioning: It is preferable to avoid reflections of light sources from shiny surfaces, such as floors and countertops. Change the position of the light source relative to the usual line of sight or use matte finishes to reduce reflections whenever possible. Light-colored countertops will reflect fewer glares than dark.
This is just an introduction to lighting and lighting application in the kitchen or bathroom. To learn more, visit the Certified Kitchen and Bath Remodeler Online Prep Course at NARI.org. QR