Comparing lumens to watts

Comparing lumens to watts

As a population we have become accustomed to judging how bright a bulb is by the wattage of the lightbulb. With the standard classic shaped household bulb, known as a GLS, we have always really known them as 40w, 60w & 100w. The same can be said for candle bulbs & golfball lamps as well, albeit with different wattages. For decades these lightbulbs used incandescent technology where a filament could be seen within the glass of the bulb. Incandescent lamps are very inefficient & consume a lot of power. For a time CFL lightbulbs, or compact fluorescent, began to replace the less efficient incandescent versions however CFL brought their own issues such as a slow warm up time & public safety concerns over mercury.

In recent years LED lightbulbs have come to replace all the previous versions & they seem to get cheaper & brighter with every month. LED lightbulbs offer large advantages over their predecessors. Extremely low wattages combined with minimal heat & a much improved lifespan has meant that LED is now the dominant technology in lighting.

Having this modern LED technology is a vast improvement in price & efficiency but it has also brought about confusion over how bright these new bulbs are. No longer can we purchase a bulb using the old process of familiar wattages. Wattage in fact only tells you how much power it takes to work a bulb. It is not a measurement of light & never has been. Light is measured in lumens & it is only recently that manufacturers have been forced to include the amount of lumens of light output that a bulb creates, on its packaging.

The good news is that, like wattage, the larger the number of lumens the brighter the bulb. The bad news is its very difficult to see a bulbs lumen output and have a comparison to the brightness of original incandescent bulbs, judged by their wattage. If you saw a 700 lumen lightbulb that uses 9w of power, would you have any idea how bright that particular bulb would be? No, neither would I! Fortunately at Lightahome we have created a simple chart that should give you a bit of a better idea when comparing lumens to watts.

lumens (light output) can be compared to wattages for different types of lightbulb as shown above
If you take a look at the above chart you can see that we have concentrated on the 3 main types of lightbulb technology. Old style (Incandescent), Halogen & LED. If you are accustomed to buying your bulbs by wattage then select the technology type (most probably old style or halogen) and then work across the chart to the wattage you would normally want to purchase. Looking up from your choice will indicate at the top of the chart what kind of lumen output you would approximately get from your choice. Following your wattage choice down the chart to the bottom would indicate which wattage of LED you would need. So for example if you normally purchased an old style 100W bulb but wanted to change to LED then you would need to be looking at something around an 18W equivalent LED bulb (or 70W in halogen). All 3 of these lightbulbs (old style, halogen & LED) would emit approximately 1300 lumens of light output. 

We hope you find the above chart useful. If you would like to purchase LED lightbulbs then we have a good range on our website 

for further advice feel free to take a look at our facebook page at 

You may also be interested in our video on how bright an LED bulb can I put in my light fitting?(below)


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