Frequently Asked Questions About Eco-Friendly Light Bulbs

Mar 1


Peter Ellinwood

Peter Ellinwood

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Buying eco-friendly light bulbs can be a challenge with so many choices now available. Many consumers are still unsure what casts the most flattering light and what equates to the most dollar savings. When it comes to deciding between CFL bulbs, LEDs, or halogen lamps, learn what to look for.

The era when buying a light bulb was as simple as buying a carton of milk is drawing to a close. Beginning on January 1,Frequently Asked Questions About Eco-Friendly Light Bulbs Articles 2012, general purpose light bulbs will need to be 30% more efficient than traditional incandescent lamps. We field questions from progressive customers regularly about eco-friendly alternatives. Here's a list of the most common inquiries.

Q: When does it make good financial sense to consider eco-friendly light bulbs?

A: Eco-friendly light bulbs are a smart choice for lamps and fixtures that are on for at least three hours a day. This is based on a September 2009 national average residential electricity rate of $0.12 per kilowatt hour. In the dozen U.S. states (1) where hourly rates exceed $0.15, two hours of daily use is sufficient.

Depending on the lamp type, you should save enough on electricity costs for a payback period under two years. And since all types of eco-friendly light bulbs last longer than traditional ones, there should be plenty of life left in them after payback.

Q: What is a compact fluorescent lamp (CFL)?

A: CFL bulbs use electric current and gas to create ultraviolet (UV) energy. In turn, this energy excites phosphors which coat the inside of the glass which creates the structure of the lamp. The phosphors transform the UV to visible light.

Many CFLs have traditional screw-in bases and are suitable, energy efficient replacements for old-fashioned incandescent bulbs.

Q: What are the benefits of CFL bulbs?

  • CFLs use less energy so they cost less to operate. CFL bulbs use roughly 75% less electricity to create the same amount of light as an incandescent bulb.
  • Less energy used means less pollution. Think about it. By reducing electricity demand, we reduce production and by extension the harmful gases that are a byproduct of electricity generation. So long as CFLs are recycled when spent (to recapture the very small amount of mercury they contain), using CFL bulbs is a great way to help the environment and our wallets
  • These eco-friendly light bulbs are designed to last a long time...typically 8,000 to 12,000 hours. Traditional light bulbs last only 750 to 3,000 hours.
  • CFL bulbs are cool. Since they generate less heat than an incandescent, CFLs can reduce air conditioning costs.
  • CFL bulbs are offered in a wide range of light colors ranging from warm white (similar to an incandescent bulb) to very cool white...virtually the same as daylight on a cloudless day.
Q: Do CFL bulbs have drawbacks that should be considered?


  • Frequent on / off switching will shorten the life of these eco-friendly light bulbs.
  • CFL bulbs don't tolerate higher temperatures well so using them in a fixture that traps heat will reduce their life.
  • The light output of CFLs will gradually dim over time.
  • Standard CFLs shouldn't be used in fixtures controlled by a dimmer switch.
  • CFL bulbs contain mercury, a toxic substance, and must be recycled properly. If a CFL shatters, it should be cleaned up carefully.
  • CFL bulbs take time to warm up to full output. At normal room temperature, 30-45 seconds is about what to expect. The cooler the room though, the longer it will take.
  • CFL bulbs used outdoors in cold temperatures will not be as bright.
  • Screw-in dimmable CFL bulbs are available but their dimming performance is inferior to incandescent and halogen lamps. They have a reduced dimming range and may flicker and cut off at the low end.
Q: What other eco-friendly light bulbs besides CFL bulbs should I consider?


  • High-efficiency halogen lamps are a great choice. These eco-friendly light bulbs, which transform infrared heat into visible light, have hit the market in the last few years. Consider HEHLs where beautiful light quality and / or superior dimmability is desired. Unlike CFL bulbs, halogen lamps last longer when dimmed consistently.
  • Light emitting diode (LED) light sources are being rapidly developed and show great promise for their high energy efficiency, extremely long life spans and light quality.
Like CFL bulbs, both of these light sources already meet the coming U.S. mandate (starting 1/1/2012) for a 30% increase in energy efficiency for general purpose light bulbs.

Q: Are eco-friendly light bulbs a good choice for the dimming fixtures I already use in my home?

A: Yes but first, keep in mind that dimming any bulb is an effective way to reduce electricity costs, carbon emissions and waste because even incandescent bulbs will last longer the more frequently they are dimmed.

Consider how often these fixtures are lit. If the fixture is lit for more than three hours per day, eco-friendly light bulbs are a smart choice.

For maximum energy savings at a reasonable cost, dimmable CFL bulbs are a good choice.

High efficiency halogen lamps are preferable if you desire superior light quality and maximum dimmability for great ambiance.

Q: When selecting eco-friendly light bulbs, how do I decide the right wattage so I get the amount of light I need?

A: Consumers have been buying traditional incandescent bulbs for so long that they've come to think of watts as the amount of light the bulb yields. In fact, "lumens" are the measure of light output at the source, while watts are the amount of electricity consumed.

The best way to choose eco-friendly light bulbs is to start by deciding how many lumens will do the job. Then read the package label and choose the lamp with this output.

As far as traditional incandescent "A" type lamps, 25 watts equals approximately 210 lumens; 40 watts=500 lumens; 60 watts=850 lumens; 75 watts=1,200 lumens; 100 watts=1,700 lumens; and, finally, 150 watts is equivalent to about 2,800 lumens.

Tip: when selecting a CFL, remember that their light output will diminish by about 25% over the bulb's life. Think about buying one with higher initial lumens than required so as their brightness fades (and your eyes age), you'll still have enough light in your space.

Q: I'm uncomfortable with the fact that CFL bulbs contain mercury. Are there mercury-free options among eco-friendly light bulbs?

A: Yes! High efficiency halogen lamps and LEDs are mercury-free.

Q: I hear a lot about LED lights. When are they worth considering?

A: Premium quality LEDs from reputable manufacturers are still expensive. For most consumers LEDs only make financial sense in light fixtures that are on at least six to eight hours a day. LEDs might make sense in these situations:

  • Recessed downlights in kitchens, family rooms or great rooms
  • Exterior lights on porches or posts or any security lights that are lit from dusk to dawn
  • Task lamps in home offices or workshops
  • Under cabinet lights in kitchens
Q: Should I replace all the light bulbs in and around my home with eco-friendly light bulbs?

A: No. We think that would be a mistake. Take a hall closet light for example: maybe it gets switched on once every other day for two minutes. Its annual electricity draw is practically nothing. Why spend $5 on a light bulb to replace one that's working just fine and costs almost nothing to operate?

Focus on the 3-5 fixtures that are on for at least 2-3 hours every day. Pick these low-hanging fruit - where electricity and pollution savings can be had for a minimal investment. If money is still burning a hole in your pocket and you want to satisfy your eco-conscience, hire a qualified energy auditor to check your home. You'll get a punch list where green investments will make much greater contributions to your savings.

Works Cited

1. AK, CA, CT, HI, NH, NJ, NY, MA, MD, ME, RI and VT

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