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How to Buy Light Bulbs

This complete guide will teach you everything about how to buy light bulbs. Here’s what you need to know.

Updated: 06/26/2024
How To Buy Light Bulbs

Lighting technology has made some pretty exciting leaps over the past few years, and outside forces such as legislation and market competition have made formerly expensive options available to everyone. But this doesn’t mean that everyone immediately got on board with new lighting trends.

If you are feeling confused about the vast selection of light bulbs in front of you at the hardware store, don’t feel too bad about it. Like most people, you probably grew up using some version of an incandescent light. In fact, people have been relying mainly on incandescent lights for nearly 140 years. So, walking into the lighting section and seeing the vast array of new options and unfamiliar terms might cause anyone to throw up their hands in frustration and walk out without getting what they came for.

This is exactly why we have compiled this complete guide to modern light bulbs. Our intention is to break everything down and take the mystery out of what used to be an utterly mundane task (i.e., buying light bulbs).

Let’s begin by talking about the different options available to you in most stores.

Incandescent Lights

Incandescent lights are what you picture when you think of the term “light bulb.” They are the glass bulbs surrounding a tungsten filament that heats up and gives off light. You have probably screwed or unscrewed dozens of these in your lifetime – which brings us to the first important point about incandescent lighting.

Energy Efficiency

If we were awarding letter grades to each type of light bulb, the old-style incandescent light would receive an “F.” Out of all your options, incandescent lights draw the most power and give off the most heat. On average, you can expect every incandescent light in your home to cost you somewhere around $5.50 each year.

Halogen Lights

Halogen lights are incandescent bulbs that use halogen gas in the glass bulb rather than argon or nitrogen, as was used in old-style incandescent bulbs. This may seem like a small difference, but it can increase energy efficiency by up to 25%.


You may have noticed that it’s becoming harder to find the incandescent light bulbs you are used to in stores. This is because in 2007, President George W. Bush signed the Energy Independence and Security Act (EISA). Among other things, this act states that the US will begin phasing out old-style incandescent light bulbs due to their energy inefficiency. Inefficient light bulbs will no longer be imported to the US, and they will no longer be manufactured here. In other words, you are not imagining things. It really is more difficult to find old style light bulbs.

Compact Fluorescent Lamp (CFL)

This type of lighting is also known simply as “fluorescent light.” While many of us recognize the long, thin tubes present in the overhead lights of many schools and offices, CFL light bulbs have also been available to consumers for many years. If you have any of those “twisty” looking light bulbs in your home right now, these are CFLs. Many people think these are a recent invention, but CFL technology has been around since the 1930s.

Energy Efficiency

CFLs offer a good improvement over the energy efficiency of their incandescent counterparts. A CFL bulb will cost approximately $1.70 in electricity each year. Furthermore, these bulbs do not draw as much wattage as incandescent lights do. This is why you will often see equivalency notations on the packaging of CFLs. For instance: “20W = 60W,” or in other words, “this bulb only draws 20 W of energy to run, but you can expect it to be as bright as the 60 W incandescent.”

Issues With Lifespan

Generally speaking, a CFL will have a significantly longer lifespan than an incandescent light. However, many consumers noticed that when CFL bulbs were turned on and off relatively rapidly, it shortened the lifespan of the bulb. So, some experts recommend the use of CFLs only in lights that tend to stay on for longer periods of time to help maximize lifespan and energy efficiency.

Light Emitting Diode (LED)

LED lights make use of a semiconductor, causing reactions on the quantum level, which release their energies as visible light. This technology was first invented in the 1960s, and it has undergone some pretty exciting transformations since then. While the first LED lights were both tremendously harsh and tremendously inefficient, the technology has been perfected to the point where LEDs can now emit many different colors and levels of light, and some can offer quadruple the lifespan of even the most efficient CFL bulbs.

Energy Efficiency

Energy efficiency is where LED lights really take center stage. An LED bulb will cost approximately one dollar per year to run. Compare that to the $1.70 of the CFL bulbs, and the $5.50 of the incandescent bulbs, and you can see how efficient LEDs are in comparison. For a long time, even though people knew about the efficiency of this light source, few made the switch because the technology was still cost prohibitive. Luckily, LED bulbs are now comparable in price to their incandescent and CFL counterparts.

Heat Concerns

You may sometimes run across information that seems to indicate that LED lights give off no heat whatsoever. This is not entirely true. While most LED lights will be cool to the touch, it is important to know that they still give off heat, as anything that draws electrical power will do. The heat from LED lights is handled by a heatsink on the bottom of each of bulb. For this reason, it’s important that you do not use LED bulbs in enclosed or deeply recessed fixtures unless they are specifically rated for that purpose.

Lumens, Watts, and What They Mean for You

Having used incandescent bulbs for so many years, we came to accept the general concept that the higher the wattage, the brighter the bulb. This is generally true, but in reality wattage is a measure of how much electricity the light bulb draws in order to work, not its level of brightness.

Brightness is measured in something called “lumens,” abbreviated “lm.” The more lumens a light bulb has, the brighter it will be. Today, when you go shopping for light bulbs, you will see some startlingly low wattage, with some light bulbs clocking in with numbers like 6 W or 8 W. But more to the point, you will also see each light bulb advertising how many lumens it gives off. This is what you want to focus on.

While there is no exact conversion formula for you to memorize, there are some handy equivalencies to keep in mind.

  • 40 W incandescent bulbs give off at least 450 lm
  • 60 W incandescent bulbs give off at least 800 lm
  • 75 W incandescent bulbs give off at least 1100 lm
  • 100 W incandescent bulbs give off at least 1600 lm

The lower wattage numbers you are seeing on some of these bulbs are actually a very good thing in terms of overall efficiency and energy costs to you. You can replace bulbs that draw 75 W of energy for bulbs and now only draw 12 W, yet still shine as brightly.

So remember: Watts are a measure of energy, but lumens are a measure of brightness.

Color Temperature

Another new term to remember is “color temperature.” Even though the word temperature is involved, this does not have anything to do with actual heat, but rather where the light falls on a scale from “warm” to “cold.” Color temperature is usually measured in degrees of kelvin.

Light that falls on the low end of the color temperature spectrum tends to be more yellowish in color. Most people have come to prefer this warmer yellowish light because it is the same type of light given off by incandescent bulbs.

As we move to the center of the spectrum, you will see light that falls more in the bright white range. Some may also call this color temperature “daylight,” as it is the closest to natural sunlight.

Progressing beyond this, we get into what many people refer to as “cold” or bluish light. In fact, this is the color that many people associate with LED lights, as the first iterations of LEDs tended to come in this harsher, brighter color.

Here are your ranges to remember:

  • Soft white light = 2700K – 3000K
  • Bright white light = 3500K – 4100K
  • Cool white light (brightest) = 5000K – 6500K

When looking to add layers of light to your interior design, it is a good idea to consider color temperatures all along the spectrum, as each has its purpose and use within the home. Ambient lighting tends to be more of the warmer yellowish light, while task lighting would be closer to the middle of the spectrum, mimicking daylight. Finally, accent lighting or lighting meant to highlight specific areas of your home or landscape, would probably be closer to the bluish end of the spectrum so that it can outshine even natural daylight.

Color Rendering Index (CRI)

Not every light bulb lists the CRI – also known as “color rendering index” – however, many choose to do so, and it is helpful for consumers to understand what it means.

CRI is rated on a scale from 1 to 100, and it refers to the light’s ability to accurately reflect colors. So, in other words, daylight would receive a CRI of 100, and any light bulbs mimicking daylight would receive that score as well. This means that colors will look the way they should.

Lower numbers may be assigned to light bulbs that give off a warmer, yellowish light, but even that will not distort colors too much. The lower the CRI rating, the less accurately you will be able to see colors in that light, and the less appropriate the light becomes for ambient or task illumination.

Lifetime Hours

The life of any given light bulb is measured in hours. This is another area where we have come a very long way since the time of Edison’s light bulb. The first electric light bulbs would last no more than a few hours before burning themselves out.

Let’s take a look at how things stack up in modern times.

  • Traditional incandescent light bulb – 1000 hours, or approximately one year
  • Halogen incandescent light bulb – 3000 hours, or approximately three years
  • CFL light bulb – 8000 to 10,000 hours, or approximately 8 to 10 years.
  • LED light bulb – 25,000+ hours, or approximately 25 years (or longer!)

As you can see, human beings have gone from measuring the lives of their light bulbs in hours, then days, and now in decades.

Special Features and Compatibility

As ready as you might be to upgrade every light bulb in your house to more efficient, longer-lasting options, it is important that you are aware of a few special cases first.


If you have dimmer switches in your home that were set up for traditional incandescent light bulbs, chances are pretty good that they will not work with CFLs or LED lights. At best, nothing will happen – but at worst, you will probably see some flickering or hear some buzzing when trying to operate the dimmer switch. Your options are to look for bulbs that are specifically rated as compatible with traditional dimmer switches or to upgrade your dimmers to be able to handle the new style of light bulbs.

Indoor/Outdoor Use

Some lights, especially CFLs, sometimes have trouble working below certain temperatures. This means outdoor lighting might begin to fail during the coldest parts of winter. Always check to make sure that your lights are rated for outdoor use, and check to see the lowest temperature at which they will still operate.

Motion Sensors

This is another case where modern light bulbs may not immediately work with dated technology. Check with the manufacturer of your motion-sensing equipment to find out which light bulbs they recommend, or consider upgrading your motion sensor so that it can be compatible with newer CFLs or LED lights.

Light Sensors

If you have lights that switch on in response to darkness, you should check to make sure these are compatible with the fixtures you have installed currently. There may be some updating required here as well.

3-Way Bulbs

3-way lamps allow for three different levels of lighting from the same lamp (i.e. low, medium, high.) While they were mainly designed to work with older-style light bulbs, some LED manufacturers are beginning to make three-way bulbs that are compatible with these lamps.

Bulb Shape

The average light bulb will come with what is known as an A19 base, but different lights in your home may call for bulbs of different shapes and sizes. For instance, a nightlight might take a C7 bulb, and a chandelier might take a CA10 bulb. It is important to know the size and shape of the bulb you are looking for, but the good news is that manufacturers of  LEDs offer bulbs in many shapes and sizes, which can accommodate every fixture in your home.

The Perfect Bulb for Typical Usage

If you’re ready to make the switch, let’s walk you through switching out the average household light bulb.

What You Have Now

A 60 W incandescent light bulb in a floor lamp. The lamp provides a soft white light and fits a standard bulb.

Terms to Look for on the Packaging of Your New Light Bulb

  • LED – LED light bulbs produce less heat, require less energy, and save you money in the long run
  • 2700K – This light temperature appears in the “warm light” or “soft white” range, like most incandescent bulbs
  • 6-12W – Look for a 60W equivalent or replacement on the LED light bulb packaging. LED bulbs require a fraction of the wattage of incandescent or CFL bulbs
  • 800 Lumen – This “amount” of light will be comparable to a 60 W incandescent bulb
  • CRI 82 (or above) – The higher the CRI, the higher the “accuracy” of the light
  • A19 Base – This is the standard size of household light bulbs
  • 20 + Year Lifetime – The longer lifetime means you pay less for light bulbs over time

Common Questions

Is It Possible to Get Warm Light Out of CFLs or LEDs

Yes! Remember to check for color temperature on each light bulb you are considering, and look for LEDs or CFLs that give off a warmer, yellowish color.

Will These New Bulbs Fit My Current Fixtures

Yes! Just remember to check the base size for each bulb you want to replace and look for the LED equivalent of the same size. For a while, many people assumed that LED lights were only available in odd shapes or in very small sizes. This is not the case, and the average LED light bulb will look very similar to the incandescent bulbs you are used to.

Is There Mercury in Fluorescent Lights

There is Mercury present in fluorescent light bulbs, but as long as the bulbs are not broken, there is no need to worry. Even if the bulbs are broken, only trace amounts of mercury will be released. Should a fluorescent bulb break inside your home, open some windows and allow the room to air out for about 10 minutes before sweeping up the debris and disposing of it properly.

Are Incandescent Lights Illegal

No. Incandescent lights are being phased out thanks to legislation, but owning incandescent lights is not illegal. You will even still see some for sale in stores, but they are usually more energy-efficient versions of the traditional incandescent light bulb.

Hopefully this guide takes some of the mystery out of how to buy light bulbs. The good news is that there are many energy-efficient and long-lasting options available to you as a homeowner, and you will see lower energy costs as a result of upgrading.

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