There are four main topics to cover:
- Light output (lumens)
- Color temperature (how warm the light looks when coming from a bulb)
Now, Rome wasn't built in a day, and we can't make you a lighting expert in 30 seconds. But give us this one page here and we'll make you an expert in most people's eyes.
Bonus Expert Tip #1: Experts are so crazy that they call light bulbs (the items that provide you with light) "lamps" and they call "lamps" (the things you put light bulbs into) "fixtures" or "luminaires." This is industry terminology, which you can use to look like a pro. But we'll stick with more common household terminology in this article.
Light Bulb Shapes
In the lighting industry, the shape of the traditional "idea" bulb is called an A19. That's because experts like to confuse people who aren't in their industry. But now you know their secret, and if you're looking online for this sort of bulb, search for A19 and you'll find what you need. You can remember this name by thinking that you get an "A" (like in school) for bright ideas.
Bonus Expert Tip #2: You don't really need to know what the letter stands for in a bulb name, but the number refers to its size. So for example, some A-shaped bulbs that provide more light could be a little larger, and you might see them as A21 and A23. They're all basically the same shape, but the size could matter depending on what kind of fixture you're putting it into.
Bonus Expert Tip #3: You can buy these and practically any other type of light bulb from Lighting Supply and then naturally be considered a genius. Plus you'll get great prices and fast shipping. For instance:
As you know, A19 bulbs are used throughout a home, like this:
But there are a few other primary shapes worth knowing about for household settings:
These are indicated by the letter G (that was easy, wasn't it?), and again, the larger the number the larger the bulb. So you'll see globe bulbs like G16, G25, and G40. These might be used as decorative string lights or in some ceiling settings, and are especially common around bathroom or vanity mirrors.
DECORATIVE or CANDELABRA BULBS:
These are the little bulbs often used in chandeliers, sconces, or some outdoor porch or post lights. "Decorative" is probably the best name for them because "candelabra" really refers to the size of the base ... and they do NOT all have the same size base.
With the rare exception of a European (E14) base, most have a candelabra base (E12) or medium base (E26). Just think of those in terms of "small" and "regular." The "regular" base is the same size as the A19 bulb you're familiar with, and the "small" is noticeably smaller -- the size of your pinky finger or smaller. So you're not likely to confuse them. If you have to replace a bulb, you should be able to tell at a glance what you need.
PAR and BR Bulbs
This is where a lot of people get confused, so pay attention and you can really save someone some grief (yourself included) when they're trying to figure out which type to choose. Take a look at these images and you'll see that PAR bulbs (left) have flat faces and BR bulbs (right) have rounded (or "bulged") faces.
So what's the point? Why do we have both of these bulbs? Think of the PA (from PAR) as standing for "Precisely Aimed" and the B (from BR) as standing for "Broad."
This is NOT what the letters really stand for, but this tip can help you to remember that PAR bulbs place their lighting more precisely and BR bulbs offer a more diffuse light. Another way to say this is that a PAR will put harder lines and shadows around its light, while a BR will blend its light more smoothly into darker areas.
What does that mean in practical terms? BR bulbs (right) are great for general lighting in recessed lighting cans (fixtures that are set into the ceiling). PAR bulbs (left) are great when you want to highlight something more specifically, whether it's a piece of art, a sitting area, or whatever.
Bonus Expert Tip #4: Bulbs like PARs and BRs also provide you with a beam angle. Maybe this sounds like another expert term meant to confuse you. But this just means how widely they spread their light -- the width of the light beam. A larger beam angle means they spread it out more. A wide beam angle is called a flood light while a narrow beam angle is called a spot light. You would normally stick with a flood BR option for general lighting.
Light Output (Lumens)
So now let's briefly talk about light output. Many people are confused by lights today because we used to choose our bulbs by wattage -- usually 25, 40, 60, 75, or 100 watts for an A19 bulb, depending on what it was used for. We knew roughly how much light that would give us (even thought it was really telling us how much energy the bulb was using). But as lighting technology advances, we get the same amount of light while using fewer watts (less energy), so you can't use wattage as an estimate of light output anymore.
Instead, we go by the term "lumens" (which basically just means "light output"). Many of today's light bulb packages will still give you an estimate of the incandescent bulbs they replace, since many people are still in the process of replacing their incandescents. (We'll talk more about these technologies later.) But it's more accurate to go by lumens, and at some point this measurement will be commonly known.
This chart from the FTC shows the approximate lumens of common incandescent A19 bulbs, so you can find bulbs of similar light output (lumens) when replacing them:
Incandescent bulbs provide us with 2700K (warm) lighting. This number goes down (gets even warmer) when you dim an incandescent. Halogen bulbs are usually slightly whiter (under 3000K). CFLs and LEDs both offer color temperatures from 2700K to 6500K (which is a very cool / cold looking whitish blue).
If you're trying to capture the warm look of an incandescent bulb with a CFL or LED, stick with 2700K bulbs. But some people prefer a crisper, whiter look, while others will choose the color temperature based on the room. For instance you might want a warm 2700K in the bedroom, TV room, living room, etc. But you might want a crisp white in the laundry room, workshop, and perhaps over the bathroom mirror. Maybe you go with something in-between for the kitchen. It's all about what feels best for you.
Bonus Expert Tip #5: As we mentioned, incandescent bulbs get an even warmer look (down to about 2200K) as they dim. If you want to upgrade to LED lights, you can get that same effect with certain bulbs. You can find these on our website by doing a search for "warm glow".
A Quick Review: Reading a Lighting Label
This is the oldest lighting technology. Incandescent lights are familiar to us all and loved by many. They have a warm look and render colors very well. They work well in both hot and cold weather, they turn on and off instantly, and they dim well on all dimmers.
The main problem with incandescent lights is that they use most of their energy producing heat rather than light, so they are extremely hot to the touch and cost a lot of money (relatively) to operate. This also makes them less friendly to the environment.
This is really a type of incandescent lighting with some halogen gasses mixed into the gasses inside the bulb. These are actually hotter to the touch than other incandescent lights. They provide light that's just a little whiter than other incandescents. They are about 30% more efficient, which is their main benefit over other incandescent bulbs. Otherwise they operate in a similar way.
CFL (Compact Fluorescent) Lighting
CFLs were an early effort to produce a highly efficient replacement for incandescent bulbs. They use only about 1/4 the wattage to produce the same amount of light, and they have the potential to last up to 10 times longer than incandescent bulbs. Those are the advantages.
But CFLs have some disadvantages too: they don't work well in the cold, most of them can't be used on dimmers, they take some time to reach full brightness, and their lives are shortened by frequent on/off switching. Many people also didn't like the quality of the light produced by early CFLs, though this has much improved. They are arguably the worst household bulbs for making colors look the way they should (called "color rendering").
While the lower energy usage is an environmental benefit (which can, in turn, reduce mercury emissions by power plants), they do contain a small amount of mercury, so special recycling is required for these bulbs.
Common household CFLs may not be around much longer, as manufacturers are looking to LEDs as the better option.
This is the latest and most efficient household lighting technology. LED bulbs use about 1/6 the energy of incandescent bulbs while producing the same amount of light. Many of them are rated to last at least 25 times longer than incandescent bulbs. And most of them dim as long as they're on compatible dimmers. (Reputable LED brands often list the dimmers that their bulbs are compatible with. Check their labels.)
There aren't many downsides to LEDs. Like incandescents, they work well in cold weather, they're not hurt by on/off switching, and they offer full brightness right away. And they do not contain mercury.
By the traditional measurement, LEDs don't render colors (make colors look like they should) as well as incandescent bulbs. But they are actually forcing a new, more detailed standard to be developed because in fact they do render colors very well -- they may render some colors even better than incandescent bulbs do.
You can find some of our best household LED deals here.
Here is our summary comparison between the different technologies:
But knowing shapes, lumens, color temperature, and technology gets you a long way in choosing most of the bulbs used in most homes. So we hope you've locked in this information and you're ready to be a light bulb expert for yourself and for the next person you see who's absolutely baffled by a lighting selection online or in a store.