Taking the ‘What?’ out of CCT and wattage

What is CCT?

Correlated Colour Temperature or CCT defines the exact visual colour appearance of a white LED. Measured on the Kelvin (K) temperature scale, CCT dictates whether a white light source appears “warm” and yellow or “cool” and blue.

CCT is typically categorised in three core brackets:

• 3000K (Warm White): Emits a soft, yellowish glow that mimics a sunset or classic halogen bulb. Ideal for hospitality settings, residential living rooms, and bedrooms where a cozy, relaxing atmosphere is paramount.
• 4000K (Cool White / Neutral White): Provides a crisp, balanced white light that encourages alertness. This is the go-to standard for retail environments, supermarkets, offices, and residential task areas like kitchens and bathrooms.
• 6500K (Daylight): Delivers a bright, high-energy light with a blue undertone that replicates natural sunlight. Ideal for high-precision task lighting, graphic design studios, and industrial non-display garages.

Wattage and lumens

Historically, when you bought a light bulb, the wattage (e.g., 60W or 100W) was the primary metric used to judge brightness. Today, wattage measures power consumption, while lumens (lm) measure actual light output.

The lower the lumens required for a space, the lower the wattage needs to be. For example, an office desk requiring clear visibility might use a high-lumen, higher-wattage fixture, whereas a standard residential corridor can achieve safety with a lower-lumen, low-wattage alternative.

Striking a precise balance between required light levels and corresponding wattage ensures excellent energy efficiency.

CCT selectable lighting

One of the greatest modern innovations for installers is CCT Selectable Lighting. Rather than purchasing or stocking three separate fixtures for warm, neutral, and cool configurations, a single modern CCT-selectable luminaire can do the same job.

The light fitting contains multiple LEDs (warm, white, etc) and a micro-switch on the back or inside of the unit allows the installer to mechanically switch between pre-set Kelvin values (such as 3000K, 4000K, or 6500K) at any point.

Some advanced commercial and premium fittings now combine CCT-selection with power-selectable (wattage) switches – so an electrician can manually select both the desired colour temperature and the power output/brightness –  offering flexibility and saving valuable shelf space.