5 things you need to know before buying LED bulbs

If you haven't switched to LED bulbs, now is the time. The reasons why are compelling. For starters, LED bulbs last much longer than incandescent bulbs, and they put out the same amount of light using significantly less energy. That's great for the environment, and it can save you money on your electricity bill in the long term. 

If you're smart home-inclined, LEDs open the door to many interesting and worthwhile features, including bulbs that change colors and bulbs that sync with your security system or voice assistant of choice. Besides, several incandescent bulbs -- including the 100-watt incandescent -- are being phased out, so you'll need to make the switch eventually in any case.

Lumens, not watts

Forget what you know about incandescents -- your watts are no good here.

When shopping for bulbs, you're probably accustomed to looking for watts as an indication of how bright the bulb will be. The brightness of LEDs, however, is determined a little differently.

Contrary to common belief, wattage isn't an indication of brightness, but a measurement of how much energy the bulb draws. For incandescents, there is an accepted correlation between the watts drawn and the brightness produced, but for LEDs, watts aren't a great predictor of how bright the bulb will be. (The point, after all, is that they draw less energy.)

For example, an LED bulb with comparable brightness to a 60W incandescent is only 8 to 12 watts.

But don't bother doing the math -- there isn't a uniform way to covert incandescent watts to LED watts. Instead, a different form of measurement should be used: lumens.

The lumen (lm) is the real measurement of brightness provided by a light bulb, and is the number you should look for when shopping for LEDs. For reference, here's a chart that shows the watt-lumen conversion for incandescents and LEDs.

As you can see in the chart above, an incandescent can draw up to five times as many watts for the same number of lumens. Get a sense of the brightness (in lumens) you need before heading to the store, and throw away your affinity for watts.

Choosing the right color LED

Incandescent bulbs typically put out a warm, yellowish hue, but LEDs come in a range of colors.

As shown off by Philips Hue, LED bulbs are capable of displaying an impressive color range, from purple to red, to a spectrum of whites and yellows. For the home, however, you're likely looking for something similar to the light that incandescents produce.

The two most popular colors available for LEDs are soft white (also called warm white) and bright white (also called daylight). Not confusing at all, right?

Soft white and warm white will produce a yellow, candle-like glow, close to incandescents, while bulbs labeled as bright white or daylight will produce a whiter light, closer to daylight and similar to what you see in offices and retail stores.

If you want to get technical, the color of light on the white light spectrum is called color temperature, and it's measured on the Kelvin scale. The lower the number, the warmer (yellower) the light. Your typical, soft white incandescent is somewhere between 2,700 and 3,500K, so if that's the color you're going for, look for that range while shopping for LED bulbs. Want something daylight toned? Look for bulbs rated at 5,000K or higher.

You'll pay more for an LED bulb (but you'll save in the long run)

LED bulbs are like hybrid cars: More expensive upfront, but cheaper to operate.

It used to be that you could grab an incandescent bulb at the hardware store for a buck or so. Then, LEDs came along -- most of them costing a lot more. Thankfully, several years of development and competition have brought prices down to the point where you'll find plenty of LED options in the light bulb aisle available for $5 or less.

But the dollars and cents don't stop there. You need to factor in the cost of using the bulb -- and the great thing about LEDs is that using them doesn't cost very much at all. For instance, a traditional 60-watt incandescent light bulb will add about $7 to your energy bill each year if you use it, on average, for 3 hours a day. A 60W-replacement LED that puts out the same amount of light will draw as little as 8 watts, and only add about a buck to your energy bill over that same year-long span.

In other words, even if the LED costs $5 and the incandescent is a freebie that you found rolling around in a drawer somewhere, the LED is still the less expensive option after less than a year of use. In the meantime, you'll enjoy less heat production, longer bulb life and even the option of controlling them with your smartphone -- and it won't burn out after a year, either.

Watch out for non-dimmable LEDs

Because of their circuitry, LEDs are not always compatible with traditional dimming switches. In some cases, the switch must be replaced. Other times, you'll pay a little more for a compatible LED.

Most of the existing dimmers in homes today were likely designed to work with incandescents. Dimmers like those work by cutting off the amount of electricity sent to the bulb in rapid-fire succession, faster than the eye can detect. LEDs draw a lot less energy, so they don't always work well with dimmers like that (here's a handy guide that goes a little deeper into the reasons why).

The first thing to do if you're buying LEDs that you want to use with a dimmer switch is to make sure that you buy bulbs that are, in fact, dimmable. Most manufacturers offer non-dimmable LED bulbs with no on-board dimming hardware whatsoever, and while those are fine if you want to save a buck or two on a bulb intended for a non-dimmable fixture, they're the last thing you want if you like the lights dimmed down low.

My second recommendation? Start with a single bulb from a major manufacturer and hang onto the receipt. Try it out with the dimmers in your home, and if it works, feel free to buy as many as you need. If not, most major retailers will be happy to let you return the bulb and exchange it for something else. At some point, you might also consider upgrading your dimmers to newer models designed to work with LEDs. Big names like Lutron and Leviton are your best bet there.

One last point: If dimming is truly important in your home, then you should really consider smart bulbs. Most use their own, built-in mechanisms to handle dimming, so you don't need a dimmer switch at all. Dimming mechanisms like those are great because they won't flicker or buzz, and you'll usually be able to sync things up with a voice assistant like Siri or Alexa, which opens the door to commands like, "set the lights to 20%."

Not all light fixtures should use LEDs

Knowing where it's OK to place an LED will ensure that the bulb won't fizzle ahead of its time.

You probably know that LED bulbs run a lot cooler than their incandescent cousins, but that doesn't mean they don't produce heat. LED bulbs do get hot, but the heat is pulled away by a heat sink in the base of the bulb. From there, the heat dissipates into the air and the LED bulb stays cool, helping to keep its promise of a long life.

And therein lies the problem: The bulb needs a way to dissipate the heat. If an LED bulb is placed in an enclosed housing, the heat won't have anywhere to go, sending it right back to the bulb and sentencing it to a slow and painful death. Remember, LED bulbs are electronic devices -- just like with your phone or your laptop, it isn't good to let them overheat. 

That's why it's fine to stick with incandescent, fluorescent and halogen bulbs for enclosed fixtures. LEDs will work, too, but in some cases, the heat build-up inside the fixture will reduce the bulb's lifespan.