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High Performance Lighting Guide

Replacement Compact Fluorescent Light Bulbs

Replacement, or "screw-in," compact fluorescent light (CFL) bulbs are a direct substitution for a standard incandescent bulb. Replacement CFL bulbs integrate both a ballast and a lamp. Replacement CFL bulbs generally last about six times longer than standard incandescent bulbs and use approximately 66% less energy.

Recommended Specification

Color: Fluorescents should be specified as 80 Color Rendering Index (CRI) and 3000 K color temperature. The CRI of daylight is 100, and so a CRI of 80 gives very good indoor color rendering. Color temperature is a measure of how “warm” or “cool” the light is with standard incandescent bulbs at 2700 K and the old cool white fluorescent at 4100 K. The color of quartz halogen lights is 3000 K and represents an excellent fresh white light. A numeric representation for the desirable properties, the number 830 (80 CRI, 3000 K) often appears printed on the bulb or on the packaging.

Ballasts: Virtually all replacement bulbs have electronic ballasts which give “instant on” and do not hum.

Dimming: Only very specially selected replacement CFL bulbs are suited for dimming. They are specifically noted in catalogs and on lamp packaging.

Dimensions: Be sure that replacement CFL bulbs fit the fixture as well as the incandescent that it replaces. CFL bulbs are usually a bit larger in dimension than their incandescent equivalent. Manufacturers continue to refine the size to come closer to the shape of traditional incandescent bulbs.

Types of Replacement, CFL Bulbs

A-Lamp Replacement: Currently, the most complete source of replacement CFL bulbs in the recommended color temperature, 3000 K, and color rendering index, 80+, (830) is the new line from Sylvania, which is available at some major hardware stores. Many other manufacturers make replacement CFL bulbs but virtually all are lower color temperature, typically 2700 K, which may be too off-color and murky to be acceptable for HPL applications. Below, a list describes the Sylvania 830 CFL bulb sizes and their approximate incandescent equivalents:

R Lamp / PAR Lamp Replacement: There are CFL replacements for incandescent R-lamps (reflector) and PAR lamps, but they are not as well developed as the standard lamp replacements described above. There are some significant shortcomings of CFL conversion reflector lamps. With poor beam control, due to the large size of the light source, the replacement R lamp may provide acceptable flood lights but they cannot replace spotlights. The lamps have slow starting characteristics, and none are currently available in the desirable 3000 K color temperature.

MR Lamp Replacement: There are currently no satisfactory replacement CFL lamps to replace small accent lights such as MR11, MR16, or PAR 20 incandescent lamps. Current fluorescent technology cannot offer the sharp point light source that gives these lamps their distinctive sparkle.

Cost

There is a considerable range in the cost of replacement CFL bulbs, plug-in CFL lamps, and linear fluorescent lamps. Replacement CFL bulbs range in cost from roughly $3 to $28 or more. Replacements for the standard incandescent A-lamps range from $4 to $8, and considering they last six times as long and use 1/4 of the electricity, they are an excellent economic choice. At the upper end of the cost range, a few replacement CFL bulbs are dimmable.