Guide to Energy Efficient Light Bulbs

Comparing Energy Saving Light Bulbs from LEDs to Fluorescent Light Bulbs

Energy efficient light bulbs are ever changing consumer landscapes with new bulbs and fixtures hitting the market every month. There are many energy saving light bulbs options to choose from that save money and reduce carbon dioxide emissions.

Today, there are three major competitors for your lighting dollars: conventional incandescent light bulbs (which will actually be phased out of many states, provinces, and countries in the coming years), compact fluorescent light bulbs (CFLs), and light-emitting diodes (LEDs). We’ll go into the details below on how each of these compare to the others, but for now, just know that LEDs are by far the most energy efficient, though they do require a higher upfront investment. Before we delve into the details, let’s cover a few helpful tips for buying energy saving light bulbs:

  • Become watt conscious: Before heading to the store, check the wattage on your current bulbs so that you know what to look for at the store.
  • Confirm size and shape: Next, look at the size of the bulb (you want your new bulbs to fit into your light fixtures and with existing lamp shades) as well as size (the size of the ballast or the screw-in part of the bulb).
  • Jot down special features: If you need dimmable lights, tri-stage lights, or those with a particular color, be sure to make note of these special features as well.

With this information at hand, you will come home with a better match for your current lighting needs.


Incandescent Light Bulbs

Remove the shades from your current lamps and you’ll likely find incandescent bulbs underneath. Using old technology (heating a metal filament wire until it glows), incandescent bulbs are the cheapest, but also the least energy efficient. Incandescent bulbs function more like little heaters since 90% of the energy used by these bulbs is converted into heat rather than light. They also have very short lifespans, shining for somewhere between 700 and 1,000 hours each.

Here are the basic specifications of incandescent light bulbs for comparison with the other energy saving light options below:

  • Purchase price (per bulb): $1.25
  • Energy costs (50,000 hours @ $0.20/kWh): $600
  • # Bulbs needed for 50,000 hours: 42
  • Total cost: $652.50
  • Fixture options: There are numerous styles for most available light fixtures


Compact Fluorescent Light Bulb (CFL)

Using a much more efficient design than incandescent bulbs, CFLs require significantly less energy and last much longer – 10,00 to 20,000 hours each. They function similarly to larger fluorescent lamps – electricity is used to excite mercury vapor, which produce ultraviolet light that causes a phosphor to fluoresce, producing light.

  • Purchase price (per bulb): $4
  • Energy costs (50,000 hours @ $0.20/kWh): $140
  • # Bulbs needed for 50,000 hours: 5
  • Total cost: $159.75
  • Fixture options: Most CFLs come with standard light fittings, making them useful in almost any light fixture.

CFLs contain mercury, which is considered a neurotoxin. However, each bulb contains about 1% of the amount in your Mom’s thermometer and about one-fifth of that in your watch battery. While this amount isn’t significant compared to other sources of the stuff (consider that a coal-fired power plants spews a ton of the toxin into the atmosphere every day), the bulbs should not be trashed with the rest of your garbage.

Thankfully, new CFL recycling programs are popping up across North America and Europe. So grab that box of spent bulbs and get ready to lighten your conscience. The two biggies accepting dead bulbs are The Home Depot and IKEA. Both have collection boxes conveniently located at all of their stores where you can drop those hard-working illuminators. Learn more about recycling CFL light bulbs.

Many conventional CFL ballasts perform poorly in cold temperatures, so be choosy when looking for a bulb for your exterior fixtures. Since some CFLs have been developed to withstand colder temperatures, a quick glance at the package’s temperature rating should help you find the right option for your outdoor application. Reflector bulbs in particular seem suited for colder duty. Average CFL lamps may function satisfactorily outdoors with delayed start-up time, but be aware that this harsher treatment may shorten their life.

ENERGY STAR has a great CFL Buying Guide to make it simple for you to find a replacement for your current incandescent bulbs.


Light Emitting Diodes (LED)

If you’ve already converted all of your light fixtures to CFLs and want a bigger challenge, consider opting for LEDs. They use at least 75% less energy than standard bulbs and last 15 times longer than incandescent light bulbs.

They come with many other advantages:

  • Instant-on functionality (unlike some CFLs)
  • Focused light allowing for precise light placement
  • Creates little to no heat, so they won’t add to air conditioning load
  • Very durable and can be used outdoors and in cold temperatures

Though they can be pricey, the money you’ll save in energy costs is significant.

  • Purchase price (per bulb): $36
  • Energy costs (50,000 hours @ $0.20/kWh): $60
  • # Bulbs needed for 50,000 hours: 1
  • Total cost: $96
  • Fixture options: Expanding product lists provide a wide range of options, including dimmable lighting

LEDs can be used in a variety of applications, including:

  • Under cabinet lighting
  • Shelf-mounted display lighting
  • Task lighting
  • Desk lamps
  • Recessed down lights
  • Wall-mounted lighting indoors and outdoors
  • Step lights outdoors
  • Pathway lighting

The flexibility of this type of lighting is due in large part to the many different styles of LED bulbs. Consider these styles, for instance:

  • Diffused lights: LEDs are clustered together and covered with a dimpled lens to spread the light over a large area. These can be purchased as high-power versions for use in fixtures where you’d use 100-watt standard bulbs.
  • Track and spotlights: In this style, the LED bulbs are again grouped together but focused more precisely, making them ideal for lighting that needs a narrower focal area.
  • Flood lights: As with the other options, these again involve many LED bulbs, but this time they are spread more widely to provide a bright, wide angle light.

When buying LEDs for your residential lighting needs, you’ll need to keep a few other considerations in mind. Most importantly, you’ll need to know how to adjust for differing brightness measurements – you buy LEDs based on lumens not on watts. This quick conversion chart should help you out with this:


LEDs - Watts

CFLs - Watts

Incandescents – Watts













Check out our light bulb recycling article, "How to Recycle Light Bulbs" to ensure that you dispose of your used bulbs properly. 


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