What should you know before buying LED Bulbs?

What should you know before buying LED Bulbs?

• The market of LED Lights is blooming very fast. Many companies serve LED Bulb to their customer and it is not easy for customer to choose best LED Bulb among them.

 • The customer does not aware the technical parameter of LED, so It becomes more difficult to find out the best quality of LED Bulbs.

 • With traditional incandescent light bulbs it was simple to get the right light bulb. If a 60 watt bulb is the broke or fused you have just get another 60 watt. When it comes to LED lighting, it’s very different. Since LED light bulbs doesn’t use the same amount of power that incandescent bulbs use.

• LED is described in terms of incandescent equivalence so we may see an LED bulb described as a 60 watt equivalent when in reality it only uses about 9.5 watts. This is because LEDs are measured by lumens (the total amount of visible light put out by a light bulb). There is not a direct mathematical comparison between the lumen ratings used in LEDs and the wattage consumed by an incandescent.

• To choose best LED Bulbs we should consider following technical Parameters.

Parameters for Choosing LED Bulbs
There are different factors to consider when choosing a suitable LED replacement bulb

Basic Technical Parameters:

• Lumen (Lighting Intensity)
• Watt (Power Consumption)
• Correlated Color Temperature (Light color)
• Color Rendering Index (CRI)
• Beam angle (Spread of light)
• Efficiency (Lumen / Watt)
• Power Factor

Other Parameters: 

• Instant Light
• Dimming capacity
• LED Driver
• LED Chip
• Weight
• Heating

Basic Technical Parameter:

(1) Lumen (Brightness): 

• When we deal with brightness of LED bulb, we must to know Lumens not Watts. 

• The amount of light emitted from a light bulb is measured in Lumens. 

• When we replace an incandescent or CFL bulb with an LED bulb we should confirm that LED bulb produces the same number of lumens that the old bulb did. 

• As a general benchmark, a standard 60-watt incandescent bulb, for example, produces about 800 lumens of light. By comparison, a CFL bulb produces that same 800 lumens using less than 15 watts • Do not use watts as a measure of brightness. 

• Lumens represent the amount of light emitted by a light source, and are a more accurate measure of the brightness of a bulb. 

• More lumens mean brighter light, fewer lumens mean dimmer light 

• 1 Foot Candle: 1 foot candle of light is the amount of light (Lumen) that generates one foot radius away from Lighting source so 1 Foot Candle= 1 Lumen / Sq.Foot 

• 1 Lux: 1 Lux of light is the amount of light (Lumen) that generates one Metert radius away from Lighting source so 1 Lux= 1 Lumen / Sq.Meter

• It is meaningless if we compare lumens between an LED bulb and a CFL to an incandescent bulb. While we are measuring lumens, we also have to consider useful lumens. 

• LED gives directional light unlike incandescent, halogen or compact fluorescent bulbs that give out omni-directional light (or light all around the bulb). If a light bulb emits light in every direction similarly over and beneath, then light that going up can get trapped in the light fitting and totally wasted.

• 50% of light emitted from a CFL or incandescent bulb is trapped inside the fitting and never makes it out and reached to objects. This trapped light is just gets absorbed and wasted as heat. • The amount of lumens that actually reached at the objects of Room that bulb produces are called as the useful lumens

(2) Watt (Power Consumption: 

• The amount of energy a light bulb consumed is indicated by Watt. 

• The watts refer to how much energy a bulb will use. 

• The lower the watts, the lower the electric bill. CFLs and LEDs have a lower wattage than incandescent bulbs, but emit the same light output 

• Watts measure power consumption, whereas lumens measure light actual brightness..

• Wattage is no longer a reliable way to gauge a light bulb’s brightness.

• In old days, when there was only one basic type of incandescent light bulb was available.consumers could buy the incandescent bulb on the term “watts” .

• Incandescent lamps use the filament material heated to the same temperature, the only way to increase their light output is to increase the wattage. We actually feel difference in brightnes between 60 Watt, 100Watt or 150 Watt light bulbs incandescent bulb.

• When new technology introduce The energy-saving CFL bulbs of 15 Watt CFL bulb produced the same light of a 60 Watt incandescent. A 25 Watt CFL was comparable to a 100 Watt incandescent in light output. 

• Generally LEDs produce the same amount of light as an incandescent bulb that has five to six times the wattage. 

• LED sources are much more efficient at converting watts to lumens. Different materials can be used within the LED sources with different light extraction efficacy so two different LED sources can consume the same number of watts but having different lumen output.

(3) Correlated Color temperature (CCT): 

• Color temperature refers to the light’s color characteristics. 

• Color Temperature is measured in Kelvin. 

• It refer to the warmness or coolness of the light that bulb produces. 

• The color temperature of a light source is a numerical measurement of its color appearance. 

• This temperature is based on the principle that any object will emit light if it is heated to a high enough temperature and that the color of that light will shift in a predictable manner as the temperature is increased. 

• Color temperature is a description of the warmth or coolness of a light source. When a piece of metal is heated (temperature increases) the color of light it emits will change. This color begins as red in appearance and graduates to orange, yellow, white, and then blue-white to deeper colors of blue. 

• Color Temperature is not an indicator of lamp heat. 

• The sun, for example, rises in morning at approximately 1800 Kelvin and changes from red to orange to yellow and to white as it rises to over 5000 Kelvin at high noon. It then goes back down the scale as it sets in evening. 

• The warm white ranges from about 2700k to 3800k, natural white ranges from 3800k to 4800k, pure white or daylight from about 4800k to 6000k. Cool white starts from around 6000k upwards. 

• Colors and light sources from the red/orange/yellow side of the spectrum are described as warm (incandescent) and those toward the blue end are referred to as cool (natural daylight). 

• In Color Temperature Value higher Kelvin temperatures (3600–5500 K) are consider cool and lower color temperatures (2700–3000 K) are considered warm. 

• When choosing a color, the two considerations are important one is color rendering (How well the light shows the true color of objects) and temperature. 

(1) Soft White / Warm White (2700K- 3000K): 

• Warm light is preferred for living spaces because it is more flattering to skin tones and clothing. 

• Recommended for indoor general and task lighting applications. 

• Living rooms • Bed rooms • Rooms decorated in earthy tones (reds, oranges, and yellows)

 • It gives effect like incident or halogen Light. 

(2) Natural / Cool White (3500K- 4500K):

 • Cool light is preferred for visual tasks because it produces higher contrast than warm light. 

• Recommended for use in Domestic Applications. 

• Warmer Whites are preferable in living and dining areas as well as reception areas to create a more relaxed environment. 

• Natural Whites are preferable for kitchens and bathrooms where tasks are performed. 

• Suitable for work areas where contrast is important. 

• Kitchen • Bath rooms 

• Rooms decorated in airy, fresh hues (blues, greens, whites) 

• It gives effect like Fluorescent Light. 

(3) Bright White (4500-5000K): 

• Recommended for use in: • Office • Study Room 

(4) Daylight / Full Spectrum (5000K- 6500K): 

• Recommended for use in: 

• Garage 

• Office 

• Industrial and hospital areas