A 40W bulb produces 470 lumens of light.
However, 40-watt light bulbs are legacy products now being replaced by efficient LED as the leading alternative.
So what is the 40W replacement in LED and how do you select it?
The lumen brightness from a 40W bulb is dependent on the type of light bulb being used.
So to find the replacement, you need to know how much light (lumens) the old 40-watt bulb produced to find the equivalent conversion.
The W in 40W refers to wattage. This is the amount of power that a light bulb uses. The higher the wattage, the more power the light bulb uses.
Lumens measure the amount of light that a light bulb emits. The higher the lumens, the brighter the light bulb is.
The more lumens (lm) created with less power (W), the greater the lumens/watts ratio and the greater the efficiency of the bulb.
As LED creates 470 lm using 5.5W of power, 40W of power used with LED would create 3418 lumens.
The lumen delivery from a light bulb is entirely dependent on the bulb technology choice. LED has fast become the more efficient lighting technology available today.
When looking at an LED light bulb, the lumen output will be listed on the packaging. This is how you can directly compare the brightness of an LED light bulb to that of a traditional incandescent light bulb.
For example, the packaging of an A19 LED light bulb might say that it is an 470 lumen light bulb. This means that it emits as much light as an incandescent light bulb that uses 40 watts of power.
To find a 40W equivalent LED light bulb, simply look for an LED light bulb with a lumen output of 470 lumens.
You might also see a light bulb that is advertised as a 40 watt replacement LED light bulb. This simply means that it emits as much light as a traditional 40 watt incandescent light bulb.
Remember, what this doesn’t tell you, however, is how much power the LED light bulb uses. To find out how much power an LED light bulb uses, you need to look at the wattage.
For example, an A19 LED light bulb that is a 40 watt replacement might use 5.5 watts of power. So even though it emits as much light as a 40 watt incandescent light bulb, it has far greater efficiency and uses less electricity.
In addition to looking at the lumens and watts of a light bulb, you might also see the kelvin (K) rating listed on the packaging.
The Kelvin scale is used to measure the color temperature of a light bulb and influences the conversion of brightness. A lower Kelvin rating means that the light bulb emits a warmer, more yellow light. A higher Kelvin rating means that the light bulb emits a cooler, more blue light.
Most 40W incandescent light bulbs have a Kelvin rating of 2700K. This is a warm light that is similar to candlelight but not quite as orange.
If you are looking for a 40W LED equivalent light bulb with a similar color temperature, look for an LED light bulb with a Kelvin rating of 2700K.
You might also see an LED light bulb advertised as a 40W replacement with a color temperature of 3000K. This is a cooler warm white light that is similar to the light you would find in a home office or bathroom.
So, when you are looking for an LED equivalent to a 60W incandescent light bulb, be sure to look at the lumens, watts, and Kelvins to find a light bulb that will give you the desired results.
For more brightness comparisons refer to our lumens chart
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