When you consider the key elements of interior design, chances are you think about overall style and functionality, materials and finishes, and spatial use, flow and feel. One aspect of design that supports and unites all these elements is lighting.
When we discuss lighting in design, we often talk about the importance of creating layers of light within a space: using a ceiling-mounted, overhead light for general illumination, focused fixtures for task lighting, and decorative fixtures for added layers of ambient light.
One attribute of lighting design that doesn’t always get as much attention as it deserves is “color temperature,” or the degree of warmth or coolness cast by a bulb’s hue. Let’s explore this important concept and how it can shape the mood of your space.
Light Bulb Color Temperature 101
Color temperature refers to the visual warmth or coolness of a lightbulb’s illuminating hue. Not to be confused with a bulb’s wattage, or brightness, color temperature is measured in degrees Kelvin (K), named for scientist William Kelvin, who heated carbon and discovered how emitted light changed at various temperatures.
Today’s light bulbs may not use heat to stay illuminated, but they still glow in a wide range of color temperatures. Higher color temperatures on the Kelvin scale are cooler and whiter, while lower color temperatures are warmer, softer, and more golden.
To put it another way: bulbs with higher K ratings have cooler (whiter) color temperatures, while bulbs with lower K ratings have warmer (yellower) color temperatures.
Warm color temperatures
At lower, warmer color temperatures, lightbulbs radiate hues from dim red to orange and yellow. Ranging from 1900K to 3400K, warm color temperatures create a cozy, earthy atmosphere.
- 1900K-2000K: Candlelight hue with warm orange-reddish tones
- 2100K-2600K: Tungsten light; orangish-yellow tones and hues
- 2700K-3000K: Early sunrise; yellowish color known as “soft white”
- 3100K-3400K: Cooler than 2700K soft white bulbs, but still warm
Warm lightbulb color temperatures are well-suited to living spaces and bedrooms. People also tend to look better under warmer light colors.
Cool color temperatures
At higher, cooler color temperatures, bulbs emit whiter, more neutral light hues. Ranging from 3500K to 5500K, cool white lightbulbs create a cleaner, radiant, and stimulating atmosphere.
- 3500K-4000K: Neutral white; middle of color temperature scale
- 4100K-4500K: Electronic flash; transitioning into fully cool tones
- 4600K-4900K: Bright morning or afternoon light; crisp white
- 5000K-5500K: Noon sunlight; bright white with mild cool hues
Cool lightbulb color temperatures work well for task lighting in kitchens and bathrooms; they also work well as a more ambient light source in rooms that incorporate white, blue, and green finishes and materials.
Full spectrum color temperatures
As the highest ratings on the Kelvin light color temperature scale, full spectrum bulbs offer a very pronounced white glow that mimics bright daylight and illuminates a space with vivid, bluish-white colors.
- 5600K-6500K: Bright overcast daylight; very cool
- 7000K-10,000K: Blue sky brightness; extremely cool
Typically perceived as too harsh or stimulating for living spaces, full spectrum color temperatures are usually reserved for residential garages as well as commercial offices and warehouses.
Choosing the Right Color Temperature
Selecting the best light color temperature for a specific space — or deciding when a space warrants a combination of lighting color temperatures — is a highly subjective process that hinges on two factors: desired ambiance and functional needs.
In the 2700K to 3000K warm light color range, the atmosphere tends to be cozy and inviting. Interior designers often use bulbs in this “soft white” range for table lamps, floor lamps, pendants, and chandeliers in living rooms, dining rooms, family rooms, and bedrooms.
Bulbs in the 3500K to 4500K cool light color range create a warm, energetic, and comfortable atmosphere. These “bright white/cool white” bulbs are often used in vanity lighting, ceiling-mounted fixtures, and outdoor fixtures to illuminate interior and exterior entryways, hallways, bathrooms, and kitchens.
In the 5600K-plus full spectrum range, lightbulb color temperature is as cool and crisp as natural “daylight.” This invigorating color temperature is best for task lighting in home offices, basements, and garages. It’s also perfect for outdoor security lighting.
To get an idea of how light color temperature can transform a space, check out the interactive light-changing feature on this Lighting Guide for Beginners.
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