But before I get too complicated, I think it’s safe to say that if you don’t have working lights now, and are buying new ones for decoration, LED is definitely the best choice.
So go ahead and replace your lights, right? Not so fast. By “replace” do you mean get rid of the working ones you have now and buy ones? It’s a bit trickier in this case, but here are some facts that might help you decide.
LED lights are better for this application in almost every way than the alternatives:
- C7 incandescent having a small candelabra screw-in base (usually indoor)
- C9 incandescent having a small candelabra screw-in base (usually outdoor)
- Mini-light strands sometimes having push-in replacement bulbs
- LED, available in several forms (including screw-in replacements for C7/C9)
Each type has a special electric strand having sockets for the bulbs, and a plug, and can usually be chained together. As you can see from the chart, the electricity use of each bulb is dramatically different. But so is the light output. To simplify things, I assumed that a single strand of lights would produce about the same amount of light, which I borrowed from this public utility writeup (pdf).
So while a single C9 bulb uses more than 70x that of an LED, strand for strand, the C9 bulbs use about 30x more electricity. Our mini-bulbs use a more modest 7.6x times as much per strand.
But this doesn’t take into account the entire cost of the product over the course of it’s lifetime. This “lifecycle” valuation is more relevant to big things like buildings and cars, but it is worth thinking about in pretty much any context when you’re buying something, especially when the reason is just “because it’s green”.
Here are a few questions that occurred to me in making our decision.
- By replace, do you mean buy a new LED strand to replace a working strand?
- Are you going to drive out to get them? How far?
- If you’re throwing out a non-working strand, could it be repaired?
- Do you already have enough lights? Could you get by with one fewer strand?
- How many hours will you have the lights on?
- Instead of buying 2 strands at $30, why not try just one strand plus 5 GE CFL bulbs for use all year round?
In our case, we should stick with the mini bulbs that we have had for a few years. They work, we have several strands, and according to my Kill-A-Watt they draw 87 Watts when on. We’ll have them on perhaps 5 hours a day for the next 30 days, or about 13kWh more than equivalent LEDs would use. At our rate of $0.22/kWh that’s $2.87 (which is about 3% of our monthly electrical use).
It doesn’t sound like replacing our current lights is the best choice for us … this year. But it’s hard to say since I don’t really know the total “burdened cost” of the product over its lifetime. It might be different if we had the regular C7 bulbs which would be closer to $10 for us. And if we had lights outside, or were replacing, it’s a sure bet. But we don’t.
Wouldn’t it be nice if products came with labels that gave us all of the information we needed to make an informed decision?