by Lorraine Horbaly
The cost of lighting the average home is about 30% of the home’s total electrical bill. Replacing incandescent bulbs with more energy-efficient lights can reduce those costs significantly. But a trip to the local hardware store reveals such a confusing array of options, claims and prices that it is hard to know what to buy. So, let’s shed some light on, well, light!
We may as well get used to it; incandescent bulbs will soon be a thing of the past. The 2007 Energy Independence and Security Act begins the phase out on January 1, 2012, beginning with the 100 watt bulb. By 2014, the 40- 60- and 75-watt bulbs will also be phased out. It might be hard to get used to, but it’s a good thing. Of the electricity used in a 100-watt bulb, 80% generates heat and only 20% creates light. So we’re doing a better job of heating our home with incandescent bulbs than we are lighting it! LEDs, (low-emitting diodes) by contrast, are the exact opposite—
80% light and 20% heat!
So, okay, we give up our incandescent bulbs but what best replaces them? We’re used to watts. We all understand how bright a 40-, 60- or 100-watt bulb is. How do we compare CFLs (compact fluorescent lights) and LEDs? The claims made on lighting packages are often confusing, misleading and sometimes downright false. So if a package says its 13-watt CFL is the replacement for a 60-watt bulb, how do we know whether it is or not?
We can know if we compare lumens rather than watts. Watts tell us the amount of energy a bulb uses. Lumens measure the amount of light emitted by that bulb. Lumens per watt are the number of lumens produced by each watt of energy. Like miles per gallon, lumens per watt give us an efficacy rating. The more lumens produced per watt of power, the more energy and cost-efficient the bulb is.
So, let’s compare. The figures below are approximate and vary from one manufacturer to another, but the numbers are representative.
Using the chart as a guide to make a decision, we can see that the CFL emits light which is 95% of a 60-watt bulb and a LED emits 78%. The number of lumens will tell the story of light output you can expect. The number of lumens per watt tells us which bulb is the most energy efficient. If you want a bulb that’s brighter than 60-watt, simply look for a higher lumen output.
At this time, CFLs are probably the better choice over LEDs. They are less expensive and have a greater lumen per watt efficacy. However, CFLs don’t last as long as LEDs, so you’ll replace them more often. CFLs also contain mercury so don’t throw burned out CFLs in your trash can. Save them up to take to a recycling facility that accepts hazardous materials.
LEDs are the light of the future. They don’t contain mercury; they are more energy efficient, longer lasting and dimmable. Already there have been breakthroughs on the efficacy rating, with one company recently achieving 200 lumens per watt! As the costs come down and lumens per watt go up, we’ll all be buying LEDs.
In the meantime, be a savvy shopper. Replace your incandescent bulbs using lumens as your guide, not watts.