Consumers are quickly warming to LED bulbs thanks to falling prices and much-improved performance over the past few years. But when it comes to the quality of light they give off, most LEDs are only as good as compact fluorescent lamps (CFLs).
The Department of Energy recently published a deep dive on consumer LED bulbs in a “snapshot” report on solid-state lighting spotted by All LED Lighting. The report found the technology behind A-type LED lamps, which come in the familiar bulb shape, has improved dramatically over the past five years. But the authors voiced some concern that consumers may be turned off to LEDs over quality, as many were with CFLs.
In the technology department, LEDs have been on a tear. The efficacy of LED bulbs in the DOE’s Lighting Facts database has nearly doubled in four years. Of the new LED bulbs that came out in the third quarter this year, the median efficacy was 78 lumens, a measure of light output, per watt, compared to 40 lumens per watt for the same period in 2009.
More important to broad consumer acceptance, though, is brightness and bulbs that produce light in all directions -- two areas that have historically been challenging for LED technology. Now, though, there are a number of products that produce as much light as traditional 75-watt or 100-watt bulbs. And while LEDs are best suited for giving off light in one direction, manufacturers have designed bulbs that mimic the omni-directional light of conventional bulbs.
The cost of LED bulbs, which can be more than $10 for a 60-watt equivalent, has also been a barrier to consumer adoption. But the introduction of many new products -- the DOE counts over 300 LED A lamps -- has led to widespread price competition.
In a separate study, the DOE found that the price LED lights overall has fallen by more than 85 percent in the last five years.
But when it comes to color accuracy, as measured by the color rendering index (CRI), LEDs so far are nothing special.
The DOE’s snapshot notes that nearly all the LED bulbs in its database have a CRI in the 80s, with the majority between 80 and 85. “This matches the typical level for fluorescent lighting, and is just above the minimum threshold for Energy Star qualification,” the report says. Only four A lamps have a CRI of 90 or higher. That level would meet Voluntary California Quality LED Lamp Specification, which was put in place to avoid the situation that occurred when CFLs were first introduced. Some manufacturers introduced cheaper, low-quality CFLs, which gave consumers a bad first impression that’s proven difficult to shake.
LED makers can develop bulbs with a higher CRI, making them closer to incandescent lamps, but that means sacrifices to power efficiency. Manufacturer Cree, for example, makes the high-CRI TW series, which costs nearly twice as much as their average-CRI counterparts. For a 60-watt equivalent, the efficiency drops from 84 lumens per watt to 59 lumens per watt.
Is having a high CRI a requirement? In general, these lights are used by photographers or in places, such as stores outlets, restaurants, or museums, where there’s a premium on accurate colors. And based on reviews of LED bulbs, consumers appear more attuned to the instant brightness of LEDs compared to CFLs and the color -- a cooler white versus the yellow of incandescent bulbs.
The California voluntary standard will give the industry more data on how consumers weigh the tradeoffs between efficiency, brightness, and quality. But as consumers get more sophisticated about lighting, they may place a higher priority on quality. “CFLs are often criticized for their color quality, which many adopters found unsatisfactory,” the DOE report notes. “Increasing the color quality of LED A lamps may be detrimental to the cost and efficacy of products, but it may also ensure consumer satisfaction.”