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Choosing the right bulb

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More choices in color appearance  -  Different colors (or temperatures) affect how the human eye perceives light. Choosing bulbs that fit your needs - whether for mood lighting, reading, or detail work - has never been easier. All bulb packaging now includes information on color appearance, brightness, efficiency, and estimated life.

Light bulb options used to be simple—and limited. Residential choices were between incandescents and tube fluorescents; shops, basements, and laundry rooms got the fluorescents and everywhere else the incandescents. The only thing to decide was how many watts you needed.

What about watts? 

Watts are a measurement of energy usage that became a convenient shorthand for describing the brightness of an incandescent bulb. Today, with so many types of bulbs to choose from, knowing the wattage of a bulb tells us little about other important characteristics: brightness, color temperature, lifetime, or environmental impact. As consumers, we need to change how we evaluate light bulbs to ensure we match our lighting needs with the proper bulbs and fixtures.

Lumens: the real measure of brightness

The lumen is a measure of the brightness of light as perceived by the human eye. It is measured independently of the type of bulb or the bulb’s wattage and provides a more accurate view of how we actually perceive the illumination. A typical 60-watt incandescent bulb provides about the same amount of lumens as a 13-watt CFL, for example. The higher the rated lumen output of a bulb the “brighter” the light is. Lowlumen output (under 600) may be best suited for decorative or mood lighting. Higher lumen bulbs (over 2,000) may work best for task lighting, especially if the bulbs are directional, such as a spotlight.

Color temperature makes a big difference

The human eye perceives redder colors as “warmer” and thus more natural for general illumination; bluer or “cooler” colors are perceived as providing sharper detail, well-suited for task lighting. All light bulbs emit different frequencies (or colors) of light, depending on the type of bulb, materials used in the manufacturing, and coatings on the inside of the glass. The lower the color temperature (measured in degrees kelvin or “K”) the warmer the light. Incandescents are typically in the range of 2,700K to 3,300K; fluorescent bulbs can range from 2,700K to “brightwhite” bulbs of 5,000K. Halogens may have color temperatures of 3,500K to 6,500K and LEDs are now available with color temperatures ranging from warm 2,700K to cool 6,000K. Choose the color temperature best suited for your use.

Labeling makes selections easier

Thanks to labeling requirements from the Department of Energy and the Federal Trade Commission, choosing light bulbs based on lumens, color temperature, and efficiency is now considerably easier. These labels also include information on estimated annual energy costs, estimated lifetime, disposal requirements, and whether the bulb meets ENERGY STAR standards. When shopping for light bulbs, consumers can more easily compare characteristics between several bulbs, and make choices to best fit their needs.

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Light bulb comparisons

The table below illustrates differences in cost, efficiency, and environmental concerns for selected light bulbs;different products may have different characteristics. Electricity costs are based on current statewide average, not projected costs. Bulbs selected for comparison have similar lumen outputs and are currently available retail products. Watts, lumen output, estimated bulb life, and retail prices are from retailers/manufacturers.

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1. Cost to keep a bulb operating 3 hrs/day at 11¢/kWh for 30 years (the estimated life of the longest-lasting bulb) plus the  cost of needed replacement bulbs.

 

2. Number of bulbs required over 30 years, operating at 3 hours per day, based on estimated life of bulbs.

 

3. Emissions per year x 30. Based on 1.8 lbs. CO2 per kWh (MN avg) for 3 hours/day of operation.