Still confused about shopping for energy-efficient light bulbs? Focus on lumens – helpfully emphasized on product packaging.
It is a common misconception that because more efficient lighting technologies, namely CFLs and LEDs – which, by law, will come to replace incandescents in common use – carry less wattage, they don’t give off as much light. Or, people just don’t know which bulbs to buy, with the newer bulbs’ wattage seeming so much lower than incandescents’ more familiar numbers: 40, 60, 75 watts.
We used to buy incandescent bulbs according to wattage – how bright we wanted our rooms to be, what our fixtures asked for. Basically, we equated watts with brightness. But, following recent changes in legislation that make incandescents less accessible – in addition to numerous studies proving that people ultimately save money and energy when they replace their old incandescents with more efficient bulbs – we need to take another look at the packaging, so we can understand how CFLs and LEDs can successfully meet our needs.
The important distinction between “watts” (the “rate of energy conversion or transfer,” says Wikipedia, i.e. the amount of electricity a bulb uses to produce light) and “lumens” – or, the total amount of light or brightness we perceive – is the answer to our conundrum. Energy-efficient light bulbs can emit just as much light (lumens) as incandescents, but use less energy (watts) to do so. That’s why they’re called “efficient.” Says SFGate’s Homeguides: “The relative efficiency of different light bulbs can be gauged by comparing how many lumens they produce for every watt of electrical power.”
With incandescents, we can look at a bulb’s wattage and know basically if it will be bright enough because we’re so used to incandescents – despite the fact that watts and brightness are not one and the same. LED News, a lighting news blog, provides a list of the most common incandescent bulbs including their wattage and corresponding brightness (lumens):
- 40 watt incandescent = 380 – 460 lumens
- 60 watt incandescent = 750 – 850 lumens
- 75 watt incandescent = 1100 – 1300 lumens
- 100 watt incandescent = 1700 – 1800 lumens
The most common light bulb used in American homes is the “60-watt incandescent.” So, how do we know how many lumens to look for when we’re (responsibly) shopping for CFLs and LEDs?
The US Department of energy recommends that consumers seeking to replace their 60-watt incandescents look for energy-efficient bulbs that produce around 800 lumens (produced by some 13-watt CFLs). To replace a 40-watt incandescent, look for around 450 lumens (produced by some 5-watt LEDs). These numbers correspond to LED News’s reporting. And where should we look for lumens?
The “Energy Labeling Rule,” as part of the EPCA (Energy Policy and Conservation Act, signed into law in 1975 in response to the oil crisis of that decade), requires that each bulb package be labeled with a “Lighting Facts” label, similar in appearance to Nutrition Facts labels on food packages. The Lighting Facts label includes brightness (in lumens), estimated yearly energy cost, life expectancy, light appearance, and energy used (in watts) – and the principal display panel on the front of the box will focus on lumens rather than watts, says the FTC’s Bureau for Consumer Protection.
All this will change the way we go about purchasing light bulbs. But the effort it’ll take to reorient our gaze to find lumens, rather than watts, in the convenient and easy-to-use Lighting Facts labels on CFLs and LEDs will be way worth the money we’ll save investing in more efficient, more sustainable products.