Incandescent Replacement Lamp Guide

a guest post by Lisa J. Reed, Lighting Designer

It used to be so easy. When it was time to replace a light bulb there was one question to answer: How many watts? But that was before lighting legislation, before energy efficient replacement options and before energy codes.

Today you have to decide whether to use halogen, compact fluorescent or LED. You have to know how many Lumens and what color temperature, plus ambient temperature, how the fixture is controlled and whether or not it is enclosed. There are scores of questions to answer before you even begin to shop for a replacement lamp.

To help you decide, here is a quick guide to the strengths and weaknesses of the three major replacement options.

Halogen Advantages

Lighting Halogen bulb
  • Just like incandescent, only more efficient
  • Classic shape
  • $3.00 energy savings over lifetime
  • Dims to 0%
  • Color temperature warms as it dims
  • Instant-on
  • Color Rendering Index (CRI) is 100
  • Can operate in any ambient temperature
  • Low initial cost
  • Lasts 2x longer than incandescent (life extended if occasionally operated at 100% brightness)

Halogen Disadvantages

  • Doesn’t save as much energy as other sources
  • Produces heat, increasing cooling load in space
  • Sensitive to vibration

Compact Fluorescent Advantages

Lighting Blog CFL image
  • Various shapes, not just spiral
  • $50-$100 energy savings over lifetime
  • Color temperature must be carefully selected
  • Color Rendering Index (CRI) over 80 is best
  • No flicker at start-up if quality CFLs are purchased
  • Low mercury options are available
  • Fairly low initial cost
  • Lasts 10x longer than incandescent

Compact Fluorescent Disadvantages

  • Doesn’t work well in cold environments without special ballast
  • Doesn’t dim without special ballast and dimming equipment
  • Requires a brief warm-up time - not best for places with quick in-and-out visits
  • Life shortened if turned on and off frequently, like with occupancy sensors
  • Use with caution in totally enclosed and vapor-tight fixtures – life may be shortened
  • Not a directional source
  • Special disposal required due to mercury content

LED Advantages

3 Incandescent Replacement Lamp Guide LED bulb IMG
  • $240 in energy savings over lifetime
  • Dimmable (to 10% and without color shift)
  • Instant-on
  • Color Rendering Index (CRI) over 80 is best; Also look for R9 value over 0, and higher is better (R9 indicates how well strong red is rendered.)
  • No mercury
  • Lasts 25x to 50x longer than incandescent

LED Cautions

  • Check for fixture size compatibility when using LED replacement lamps
  • Inherently sensitive to high temperatures – look for a good heat sink
  • Some flicker, especially with incompatible dimmers or transformers
  • The technology is still working out some of the "kinks"

LED Disadvantages

  • Highest initial cost
  • Most replacement lamps don’t work in completely enclosed fixtures

Have a question? Post a comment below and we'll help.


Lisa J Reed photo - Lighting Blog

Lisa J. Reed has been attracted to lighting (like a moth to a flame) for 20+ years. She is the Founding Principal at Envision Lighting Design, LLC in St. Louis, where she designs, teaches, and writes about architectural lighting.


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