I am listening to this program about energy efficiency on PBS. They stated that in terms of light to heat ratio, the incandescent light produces 5% light and 95% heat, and a LED light produces 25% light and 75% heat.
My observation is that despite the LED light’s 5 times higher efficiency, there is still plenty of room for improvement in LED light efficiency.
They also talked about the lifetime of the LED lights. They said that the LEDs may never fail, but the rest of the electronics will probably not last as long as the LEDs. From my experience, LED lights have one large electrolytic capacitor and 1 or more smaller ‘lytics. Typical ‘lytic caps dry out and/or leak their electrolyte after several years, and then they cease to function. ‘lytics are inexpensive, but the LED light has to be opened up to replace them. If replacement was easy to do, the light could be repaired. But that would postpone buying a new LED light, so manufacturers would not allow it in the design.
Old radios and TVs had vacuum tubes in sockets so they could be replaced, but modern electronics has been designed to be so cheap that it is more economical to buy a new one than to repair an old one. That put a lot of radio and TV repair shops out of business. The automotive supply stores charge a Core Charge for auto parts such as alternators and starters. Such a core charge could be charged for LED light bulbs. More people would bring their LED lights in and exchange them for a new one and keep them from ending up in a trash can.
When one thinks about it, there is a strange backwardness to LED lights. The incandescent lights lasted only a thousand hours or so and had to have a socket so they could be replaced. This has had a complete reversal with LED lights. The LED may last a lifetime but the circuitry, which could’ve been included in the socket, lasts only 5 years or so. Perhaps the LEDs should have a socket for replaceable circuitry.
I should point out that some LED lights have simple circuits. Typically these are the least expensive ones. The LEDs are connected in series and the AC current is limited by a capacitor. This capacitor is supposed to be type X2 for connection across the AC line, but I’ve seen circuits without X2. Depending on the circuit some lights have rectifier diodes. But the circuit may not have electrolytic capacitors, which may allow the light to last longer. Also, simpler circuits have fewer parts to fail than more complex circuits. Thus, in other words, cheaper lights might last longer than more expensive lights.
Manufacturers have tried to extend the life of the bulb by adding metal heat sink fins to the base to keep the circuitry cool. It costs more, though. The conditions in the fixture, especially the temperature, are so variable that the LED light lifetimes are difficult to predict. The lifetime could be a year or less in a hot fixture with a LED light that runs hot, to the the 22 years, that are often claimed by the makers, in a cool fixture.
Why do fixtures run hot or cool? The temperature wasn’t important with incandescents. But it is with LEDs.
One other important thing about LEDs that I have been reading about lately. It’s called externalities. When a light uses energy, it creates such things as CO2 greenhouse gas, heat, and even mercury (burning coal releases mercury). The less electricity the light uses, the less externalities it causes. So saving electricity should be a primary goal of any light. The most efficient form of energy is the energy you don’t use.
Update – Just a thought. I have an old gooseneck table lamp that has a twist switch that was baked by years of heat from incandescent lamps until it will no longer twist. So I give the LED light in it a partial turn to turn it off. Unlike the hot incandescent light, the LED light stays cool enough to touch after being on for a long time. This makes it possible to use the light itself as the switch. Well I thought it was an idea bright enough to blog! No pun intended.
