Lighting Tips

Tips for Buying High Efficiency Bulbs

It can be a daunting task to figure out how to switch your bulbs from incandescent to fluorescent. You know you want to do it because it will lower your electricity bill, but you don’t know how to get the right bulbs for your fixtures. You want to keep the same type of lighting and avoid the cold blue light you have so often seen in fluorescent lights. This handout will help you make the right choices at the store.

What Fluorescents are sold at the store?

Compact fluorescent lamps are the work horses of high efficiency lighting. If you have not tried CFLs recently, please do so. The reliability and the light colors are much better than the first CFLs that came on the market in the early 2000s.

When you start shopping for high efficiency light bulbs or “lamps”, you will see that there are several new things to consider. (In professional lighting lingo, a ‘bulb’ is called a ‘lamp,’ and what you call a ‘lamp’ is called a ‘fixture’ by the pros.) Let’s take a look at what you will need to know.

Although many packages will help you by providing the wattage equivalents, to figure out what you need you it is helpful to know about these:

  • Lumens
  • Color temperature
  • CRI
  • Dimmable or not

Lumens: How bright will it be? The quantity of light put out by a ‘bulb’ is measured in lumens. An old style 60 watt incandescent light bulb puts out about 800 lumens.

Color temperature: How warm will the light be? The color of the light is measured in degrees K (Kelvin). The higher the ‘color temperature,’ the whiter the light. (Think ‘white hot’ versus a candle.) Thus a warm yellowish color is around 2700 degrees K, while the color temperature in a retail store is typically around 4100 degrees K. A hospital operating room might have lights with a color temperature of 6000 degrees K. Lights labeled ‘warm white,’ have a color temperature is in the 2700 – 3000 K range. “Daylight” is in the 4000 K range.

CRI: How will colors look in the light? Color rendering index refers to the ability of light falling on an object to show its true color. Have you been in a parking lot at night where it’s difficult to tell the color of the cars? That’s because the lights have a low CRI. If you want to see the colors in your food, or the art on your walls, you want lights with a high CRI. The index tops out at 100. Incandescent lights have a CRI of 100. Compact fluorescent lights have a CRI of around 82. Most LED lights have a CRI of around 75 – 80.

Dimmable lights:

Yes, you can have energy efficient dimmable lights. However, you need to select the right one. Here are some of your choices.

CFLs: Many compact fluorescents are labeled “dimmable,” but they give very poor performance. Unless you are paying over $10/lamp, you can expect to be returning them to the store where you bought them. Caveat: Some manufacturers make CFLs that are specially matched to dimmer switches. You buy the lamps and dimmers together. These perform very well, but you have to change the dimmer switch. No biggie for a handy person.

CCCFL: Cold cathode compact fluorescent lamp. These are the real ‘dimmable’ CFLs. They cost more than regular CFLs and use a bit more energy than regular CFLs, but way less energy than incandescent lamps. You can use them on any type of dimmer. Color rendering index is typical of CFLs, around 82.

LED lights: They are not dimmable unless you connect them to a special custom ballast. They are very expensive but use very little energy, less than half that of a compact fluorescent and one tenth that of an incandescent. A few years from now, we will start to see them everywhere. Best application right now is for security lighting where lights are on continuously for 12 to 24 hours/day.

Buying Lights

Replace all lamps at one time: If you are thinking about installing more efficient lighting, then replace all lights at once. Do not wait for old incandescent lights to burn out. It’s actually cheaper to replace an incandescent bulb, even if just installed yesterday, than to operate it until it burns out.

Before you go shopping, be sure to:

1. Take an inventory of the types of fixtures you have. Some have sockets that will not accept fluorescent bulbs (such as small high intensity lamps).
2. Note what wattage you are currently using in each lamp.
3. Look at the room and consider if you want a warm or cool color: “Warm white” is a lower temperature than “daylight.”
4. Note which fixtures are dimmable. Plan to order cold cathode CFLs on-line, or get new dimmer switches that are matched to new ‘lamps’ (bulbs).
Finally: Don’t forget to consider vacancy sensor switches for circuits that tend to get left on when rooms are unused. Vacancy sensors turn off the lights auto-magically after everyone leaves.

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