Published on September 1st, 2011 | by Elizabeth Smyth59
LED vs CFL — Which Light Bulb is More Efficient?
When it comes to lighting our homes, we are encouraged to switch outdated incandescent bulbs to more energy efficient alternatives. And, most often, these alternatives are LED and compact florescent lights (CFL).
The decision between the two is often based on some variation of the following assumptions: LEDs are more efficient than CFLs. LEDs also cost more than CFLs but they last longer, so you’ll make up the initial cost over the lifetime of the bulb.
Since about 74% of US houses have at least one energy efficient light source in them, I assume this internal discussion happens quite often in the lighting aisles of home improvement stores. So, are these assumptions about LED vs CFL really true?
To determine whether a residential LED bulb is more efficient than a comparable CFL bulb, energy efficient commercial lighting manufacturer Precision Paragon [P2] conducted a small comparison in “real world settings.” That is, the performance output of the bulbs was calculated in a residential setting and not in the controlled environment of a laboratory.
The reason for the distinction between the “real world” and the lab are the components that must work together to turn electricity into light. In a lab, which can be controlled for the best possible conditions, light can be generated at optimal efficiency. Because manufacturers are able to utilize components that are made to work together, they can claim to produce results with greater efficiency.
For instance, a leading LED-chip manufacturer announced they had achieved an efficiency of 231 lumens per watt in an LED chip. However, this was conducted in a lab where technicians were able to use lighting fixtures capable of producing such high output. In the “real world,” this LED-chip manufacturer does not sell a LED lighting fixture with a claimed efficiency over 75 lumens per watt. Therefore, among other factors, consumers would not be able to produce as high efficiency in their own homes.
The Comparison of an LED Bulb versus a CFL Bulb
For the study, P2 used two roughly equivalent CFL and LED lamps that would commonly be used in the home. Representing LED — the Philips AmbientLED 12.5W A19 Indoor Bulb — and representing CFL — the GE Energy Smart 13 Watt bulb, a fairly common bulb available in most any department or hardware store.
When comparing the two on paper, the efficiency of the bulbs is nearly identical, within 0.5 lumens per watt. However, with the “real world” being taken into consideration, there are certain environmental and consumer factors that make a case for both.
One factor is cost. If your primary concern is price, the CFL would be a better choice. Although the CFL has a shorter lifespan, even if you replaced the CFL three times to achieve an equivalent lifespan to the LED, you’d still have only spent $2.58 in comparison to the LED’s $45 initial purchase price.
Another factor is location. If the fixture you’re mounting the bulb in is in a place where it’s a hassle to change, that $40 difference might be worth not having to deal with it for the expected 20+ years of normal usage you’ll get out of the single LED.
The bottom line is that in a household setting, where optimal components and ideal conditions cannot be controlled, the LED and CFL light bulb are very close competitors. The decision for one over the other should be made based on the goals of the project and you may even require a mix of technologies to meet those goals.
Source: [P2] Is LED The Most Efficient Lighting Technology?