“Electricity Prices Plummet,” The Wall Street Journal, August 12, 2009
Hey, is there a recession going on? This timely article details how slack demand for electricity in 2009 may lead to the first consecutive year decline in electricity use in the U.S. since 1950. Such news may tempt some consumers to relax an otherwise robust commitment to reducing home and business electricity consumption. Conservation and energy efficiency are hard work, and harder still to turn into regular habits, especially when energy costs are low.
However, with days growing shorter and nights growing longer as we head into autumn, lighting costs will be on the rise for consumers, even if rates per kilowatt hours are ticking down. Now may be the best time to make a switch to more efficient, energy-saving light bulbs to reduce energy consumption, but there is no need to get carried away. Instead, we suggest folks start slowly with a deliberate approach that targets fixtures that are lit most frequently and for the longest periods. This often leads our customers who want to reduce energy consumption outside.
Green Light Bulbs Reduce Energy Consumption
Exterior fixtures come in as many configurations as indoor lights and they mainly serve three purposes: security lighting, accent lighting and convenience lighting. In some cases, single fixtures perform double or even triple duty.
The greatest savings, in both dollars and reduced carbon emissions, are most easily realized by installing energy-saving light bulbs in any fixtures which are lit from dusk-to-dawn but aren’t controlled by a motion sensor. This could be a floodlight above the driveway or back deck or a pair of decorative sconces or lanterns straddling the front entrance. Post lights are commonly lit all night as well. If you’re like us, you get peace of mind knowing that these lights make the home look very much occupied while you sleep.
Choosing energy-saving light bulbs with the highest efficiency ratings for the amount of light desired will reduce energy consumption and have the greenest impact. Consider this comparison:
Table 1: Traditional (Incandescent) Bulbs
| Watts |
Lumens |
Efficiency (Lumens/Watt) |
Annual Use (Hrs)1 |
Annual Cost to Light2 |
CO2 Emissions (Lbs)3 |
|
25 |
200 |
8 |
2,920 |
$8 |
97 |
|
40 |
500 |
13 |
2,920 |
$13 |
155 |
|
60 |
850 |
14 |
2,920 |
$20 |
233 |
|
90 |
1,400 |
16 |
2,920 |
$30 |
349 |
Table 2: Energy Efficient Bulbs
|
Watts |
Lumens |
Efficiency (Lumens/Watt) |
Annual Use (Hrs)1 |
Annual Cost to Light2 |
CO2 Emissions (Lbs)3 |
|
5 |
200 |
40 |
2,920 |
$2 |
19 |
|
9 |
425 |
47 |
2,920 |
$3 |
35 |
|
15 |
825 |
55 |
2,920 |
$5 |
58 |
|
26 |
1,300 |
50 |
2,920 |
$9 |
101 |
Notes:
18 hours per day
2National average residential retail price of electricity per kilowatt hour of 11.38 cents; year-to-date through May, 2009. Rates vary significantly by region. Source: Energy Information Administration.
31.33 lbs of CO2 per kilowatt hour. Source: EPA.
Look at the third row of each table: $15 annual savings per socket is more than enough to upgrade to energy-saving light bulbs in order to reduce your energy consumption. Your energy efficiency investment will be paid back in less than one year. As for CO2 emissions, a 75% reduction won’t do your eco-conscience any harm.
For homes, Compact Fluorescent Lamps (CFLs) are a solid choice for dusk-to-dawn lighting scenarios. They’re available in a wide array of wattages, shapes (including decorative), sizes, and colors and are typically designed to last 8,000 hours or more. One drawback of CFL energy-saving light bulbs in an exterior setting is that they’re affected by ambient temperature. Our advice: if you live in a colder climate, look for lamps with “amalgam” technology for best performance or buy ones with the next higher incandescent watts equivalent (example: if you’re replacing a 60 watt incandescent, buy a CFL equivalent to a 75 watt bulb). Also, if a fixture isn’t weather protected, be sure to select a bulb rated for use in a wet location.
Light Emitting Diode (LED) lamps are hitting the market at a rapid pace and are also worth considering for their superior ability to reduce energy consumption and extremely long life. Interestingly, LEDs don’t emit ultraviolet light and don’t attract insects. For an overnight fixture near a door, an LED would be a good alternative to a yellow bug lamp. Advice: insist on UL listed LEDs (not easy to find) for safety’s sake. Harder to find still are LEDs which are UL listed for use in a wet location so be choosy here.
Energy-Saving Light Bulbs for Motion Sensors and Electronic Timers
For multiple reasons, energy-saving light bulbs, such as CFLs, are a poor choice for fixtures that light automatically by motion detection. These are typically used for security purposes but are also a feature of garage door openers. CFLs are not engineered to produce short bursts of light and their electronics aren’t generally compatible with sensors. Thus, a traditional incandescent bulb is a fine choice (and probably what’s in the fixture now). Advice: when the existing bulb burns out, consider a high-efficiency halogen lamp to reduce energy consumption. Currently, these energy-saving light bulbs are 30 to 40% more energy efficient than traditional incandescents. Expect these savings multiples to grow as lighting manufacturers continue to improve their halogen technology in anticipation of lighting efficiency requirements that go into effect in 2012.
As for LEDs, while they do reach maximum brightness instantly, they are still very pricey and thus not a good investment for the short bursts of light delivered by motion control sensors. Prices will come down as demand increases for energy-saving light bulbs. Advice: wait.
Some people rely on electronic timers to switch on exterior lights as darkness settles in. Again, CFLs aren’t suited for this application. In this application, once on, the light may remain lit during overnight hours; an LED lamp, which generally works with electric eyes (check with the manufacturer) would be an excellent choice to reduce energy consumption and extend bulb life versus an incandescent bulb.
Fall’s the Time to Make the Switch to Energy-Efficient Exterior Light Bulbs
They say that the cheapest, cleanest kilowatt hour of electricity is the one that is never produced in the first place. As the shorter days of fall approach and your energy demands grow, put on your green glasses and look at the lighting fixtures outside your home. You’re almost certain to find opportunities to reduce energy consumption and live more lightly with energy-saving light bulbs.

