Lumens measure the total amount of visible light emitted by a source. More lumens mean brighter light. This is the most accurate way to compare the brightness of different bulbs, especially LEDs vs traditional bulbs.

Lux measures illuminance, or the amount of light (lumens) falling on a specific surface area (per square meter). 1 Lux = 1 Lumen per square meter. It tells you how bright a surface will appear, considering the distance and spread of the light.

Kelvin is the unit used to measure Correlated Color Temperature (CCT). It describes the appearance of the light, from "warm" (yellowish, lower K values like 2700K) to "cool" (bluish, higher K values like 5000K+).

• Warm White: ~2700K - 3000K
• Neutral White: ~3500K - 4000K
• Cool White/Daylight: ~5000K - 6500K

CRI measures how accurately a light source reveals the true colors of objects compared to natural daylight. The scale is 0-100, with 100 being perfect color rendering (like sunlight). For general lighting, a CRI of 80+ is good, while 90+ is excellent for tasks where color accuracy is important (e.g., retail, art studios).

Beam angle measures the spread of light from a directional bulb (like a spotlight or downlight). A narrow angle (e.g., 15°-40°) creates a focused spot, while a wider angle (e.g., 60°-120°) provides broader, more general illumination. The angle is measured where the light intensity drops to 50% of its maximum.

An LED driver is an electronic device that regulates the power supplied to an LED or string of LEDs. LEDs require specific DC voltage and current to operate correctly. The driver converts the AC mains voltage to the required DC voltage and controls the current to prevent damage and ensure consistent light output and longevity.

IP ratings classify the degree of protection provided by an enclosure against intrusion from solid objects (like dust) and liquids (like water). The rating consists of two digits:

• First Digit (Solids): 0 (no protection) to 6 (dust-tight).
• Second Digit (Liquids): 0 (no protection) to 9 (high-pressure, high-temperature water jets).

For example, IP65 means dust-tight and protected against water jets from any direction – suitable for many outdoor applications.

Watts (W) measure energy consumption – how much power a bulb uses. Lumens (lm) measure light output – how bright the bulb is.

With older incandescent bulbs, higher wattage generally meant higher brightness. However, LEDs are much more energy-efficient. An LED can produce the same amount of light (lumens) as an old incandescent bulb while using significantly fewer watts. Always compare lumens to determine brightness, not watts.

LEDs have a very long lifespan compared to traditional lighting technologies. Quality residential LEDs typically last between 15,000 and 25,000 hours, with some lasting up to 50,000 hours or more. This translates to many years of use under normal operating conditions (e.g., 3-4 hours per day).

Lifespan is often rated as 'L70', meaning the point at which the LED has dimmed to 70% of its initial lumen output. Factors like heat management, driver quality, and usage patterns can affect actual lifespan.

Many LED lights are dimmable, but not all. You must check the product specifications or packaging to confirm if an LED bulb or fixture is designed for dimming.

Furthermore, you often need a compatible LED dimmer switch (sometimes called a trailing-edge or CL dimmer). Using a non-dimmable LED with a dimmer switch, or using an incompatible dimmer, can lead to flickering, buzzing, poor performance, or damage to the bulb or dimmer.