Living Efficiently With Tom: Efficient Lighting
June 27, 2010 – Changing out inefficient light bulbs is an easy and cost-effective way to cut your energy bills. Replacing a 60 Watt incandescent bulb with a 13 Watt compact fluorescent (CFL) one can save you almost $60 over the life of the CFL – a payback period of about five and a half months.
Look for the ENERGY STAR label when purchasing CFLs. Bulbs that qualify for the label meet certain requirements for performance, quality and low mercury content.
And speaking of mercury, make sure you dispose of broken, burned-out or faulty CFLs properly – don't simply throw them in the trash, as mercury is toxic. Instead, take them to a collection point for CFLs, which can be found at almost any hardware store (however, you would normally get more mercury exposure from eating a can of tuna than you would smashing a CFL bulb).
Number of bulbs
Though you might be inclined to max out the power of bulbs in a given fixture, give some thought to exactly how much light you actually need.
With CFLs and LEDs drawing less energy than incandescents, you can put a lot of lighting into fixtures with limited wattage or amperage. But do you really want to do that? If you put, say, three 100-Watt equivalent CFLs into a fixture that previously had three 30-Watt incandescent bulbs, you won't be saving energy – which is the whole purpose of using CFLs in the first place.
Instead, consider supplementing ceiling lights with standing and table lamps, and turn on only as much light as you need at a given time. If you're sitting on the sofa reading a book, all you need is a single-bulb standing lamp nearby – not a triple-bulb ceiling fixture that lights up the entire room.
When replacing light fixtures, look for the ENERGY STAR label. These will accept plug- or snap-in bulbs, with much of their electronic componentry built into the lamp rather than the bulb (as is the case with screw-cap CFLs). That way, when the bulb burns out it will be cheaper and less wasteful to replace.
Brightness (lumens)
Nearly all screw-cap CFLs are labeled with a number that compares their brightness to the wattage of an incandescent bulb of similar brightness. You can also compare lumens, which are a measure of brightness: 1,100 lumens roughly corresponds to the light of a 75 Watt incandescent bulb. Lumens, like watts, are noted on the product's package; by comparing the two numbers across brands and styles you can see which bulb is more efficient (yes, some CFLs are more efficient than others).
Color Temperature (Kelvin)
The light from CFLs is occasionally described as being 'harsh' or 'blue.' But these days it's easy to find a range of different color temperatures (expressed in Kelvin (K)), from 5000K 'daylight' or 'cool white' to 3000K 'warm white.' If you prefer the warmer, orange-ish tone of incandescent bulbs, look for CFL or LED bulbs closer to 3000K. Remember that shades and fixture covers will also change the light's tone.
Somewhat confusingly, bulbs that produce 'warm white' lighting actually have a lower color temperature than bulbs that produce 'cool white' light. The aesthetic distinction is entirely based on people imagining red to be warm and blue to be cold. In reality, the higher the Kelvin (or, the higher the color temperature), the cooler the color.
In picking out different bulbs for different rooms of our house, I varied the color temperature based on the room. I chose warm-toned bulbs for the bedroom and living room and cool-toned (i.e., whiter) bulbs for the kitchen, office and bathroom as well as for outdoor fixtures.
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| An LED bulb in my front porch light |
Some thoughts on LEDs
Light emitting diodes (LEDs) have been around for a while, but it's only in the past few years that they've been incorporated into general-purpose space lighting. Generally speaking, LEDs are extremely energy-efficient – yet they are also expensive. Thankfully, LEDs are coming down in cost and new, better designs for general lighting are taking to market. We will be seeing a lot more LEDs on the market in the coming years.
LEDs are best suited for directional lighting like flood lights; because of their relatively high cost, they are best used in places where the lights are on much of the time, thus generating savings faster.
Beware, though: an inefficient LED light can use more energy than a good CFL, so look closely at the light output (in lumens) and energy consumption (in Watts) before you buy. Many LED bulbs are also marketed as 'accent lighting'. This means that while they may not emit enough light (lumens) to light up a space, they can be used to interesting aesthetic effect - as in the photo at right.
Resources
- ENERGY STAR light bulbs
- ENERGY STAR light bulb savings calculator [XLS] (this calculator uses slightly different assumptions than those the Alliance uses for its savings calculations)
- LED holiday lights
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