LED vs Incandescent vs Halogen vs CFL: A Complete Comparison

For most of the last century, choosing a light bulb meant choosing a wattage. Today the decision has more layers. Thanks to federal efficiency rules, the bulbs you'll actually find on the shelf have changed for good. Four technologies still shape the conversation: incandescent, halogen, compact fluorescent (CFL), and the light-emitting diode (LED). Each creates light in a fundamentally different way, with real differences in energy use, lifespan, running cost, light quality, and even what you're legally allowed to buy.

This guide compares the four on the factors that matter to a real purchase, whether you're specifying a commercial retrofit or replacing a single burned-out lamp, and explains where the U.S. market is clearly heading. The short version: LED has become the default for nearly every application, but understanding why helps you choose the right one rather than just the cheapest.

The Four Bulb Types at a Glance

Before the detail, here's how the technologies stack up on the numbers buyers ask about most. Figures reflect typical mainstream products; specialty lamps vary.

* Manufacture and sale of most general-service incandescent and halogen bulbs ended in the U.S. in 2023. Certain specialty types remain exempt, and bulbs you already own are still legal to use (more on that below).

How Each Bulb Makes Light

The way a bulb produces light explains almost every difference in the table above, from efficiency to heat to lifespan.

Incandescent

An incandescent bulb runs electric current through a thin tungsten filament until it glows white-hot. It's a beautifully simple design that gives warm, flattering light with perfect color accuracy. The catch is physics: roughly 90% of the energy leaves as heat and only a small fraction becomes visible light, which makes incandescent the least efficient and shortest-lived option of the four.

Halogen

Halogen is a refined incandescent. The tungsten filament sits inside a small capsule filled with halogen gas, which recycles evaporated tungsten back onto the filament. That "halogen cycle" lets the filament run hotter, producing brighter, whiter light and a modestly longer life with slightly better efficiency than a standard incandescent. It still runs very hot and remains far behind newer technologies on energy use.

CFL (Compact Fluorescent Lamp)

A CFL is essentially a fluorescent tube shrunk and curled to fit a standard socket. Current excites a small amount of mercury vapor, which emits ultraviolet light; a phosphor coating inside the glass converts that into visible light. CFLs use around 70% less energy than incandescent bulbs and last several times longer, which made them the go-to upgrade in the 2000s. Their trade-offs are a brief warm-up to full brightness, limited dimming, and a few milligrams of mercury that require careful disposal.

LED (Light-Emitting Diode)

An LED produces light by passing current through a semiconductor, which emits photons directly, with no filament to burn out and no gas to excite. That efficiency is why LED bulbs and lamps now dominate: they deliver the most light per watt, last the longest, turn on instantly at full brightness, run cool to the touch, dim well with the right control, and contain no mercury. Early LEDs drew criticism for harsh color and high prices, but both issues have largely been solved.

Energy Efficiency: Lumens per Watt

Efficiency is measured in lumens per watt (lm/W), which tells you how much light you get for each watt of power. Incandescent bulbs manage only about 10–17 lm/W, halogens roughly 15–25, CFLs around 50–70, and modern LEDs anywhere from 75 to 180 lm/W, with mainstream household lamps comfortably above 100.

Put another way, to produce the ~800 lumens of a classic "60-watt" bulb, an incandescent needs about 60 watts, a halogen about 43, a CFL roughly 13–15, and an LED only 8–10. This is exactly why the industry has shifted from shopping by watts to shopping by lumens. If that distinction is new to you, our guide on lumens versus watts breaks it down with examples.

Lifespan and Maintenance

Lifespan is where the gap becomes dramatic. A standard incandescent lasts around 1,000 hours; a halogen about 2,000–4,000; a CFL roughly 8,000–10,000; and an LED commonly 15,000–50,000 hours, with 25,000 a typical rating. At a few hours of use per day, an LED can run for well over a decade.

For homeowners that means fewer trips up the ladder. For facility and property teams it means something bigger: labor. Replacing lamps in a warehouse, parking structure, or high ceiling often costs more in time and equipment than the lamps themselves, so a longer-lived source quietly cuts maintenance budgets year after year.

Upfront Price vs. Total Cost of Ownership

LEDs cost more per bulb than the alternatives, and that sticker price is the main reason people hesitate. But the upfront cost is only a sliver of what a bulb actually costs to own once you count electricity and replacements.

Consider one socket running a 60-watt incandescent versus a 9-watt LED over the LED's 25,000-hour life, at a U.S. average rate of about 17¢ per kWh. The incandescent burns roughly 1,500 kWh of electricity; the LED about 225 kWh. That's near $215 in energy savings, before you add the cost of buying and changing the 20-plus incandescent bulbs you'd go through in the same period. Net lifetime savings land well above $200 per socket, and they multiply fast across a whole home or building.

Light Quality: Color, CRI, and Dimming

Efficiency isn't the whole story. How the light looks and behaves matters just as much, especially in living spaces and retail.

Color temperature (Kelvin)

Color temperature describes whether light looks warm or cool, measured in Kelvin (K). Around 2700K reads as warm and cozy, 3000K as soft white, 3500–4000K as neutral, and 5000K as crisp daylight. Incandescent and halogen are effectively locked into a warm 2700–3000K glow, while CFLs and LEDs are sold across the full range, so you can match a bulb to the room rather than the other way around.

Color rendering (CRI)

The color rendering index (CRI, on a 0–100 scale) measures how accurately a light source shows the true color of objects. Incandescent and halogen sit near a perfect 100. Good LEDs typically range from 80 to 95-plus, and CFLs around 80–85. For kitchens, bathrooms, showrooms, and anywhere color matters, look for an LED rated 90 CRI or higher.

Dimming and warm-up

Incandescent and halogen bulbs dim smoothly and turn on instantly. CFLs take a moment to reach full output and most can't dim at all. LEDs are instant-on and dim beautifully, but only when paired with a compatible LED dimmer. Using an old dimmer built for incandescent loads is the usual culprit behind flicker or buzz, so matching the control to the bulb is worth the small extra step.

Heat Output and Safety

Because incandescent and halogen bulbs convert most of their energy to heat, they get genuinely hot, enough to pose a burn risk and, in enclosed or unventilated fixtures, a fire concern. In air-conditioned spaces they also add to the cooling load. CFLs run warm, while LEDs stay cool enough to handle moments after switching off, which makes them a safer fit for closets, recessed cans, and fabric-adjacent fixtures.

Environmental Impact and Disposal

Every CFL contains a small amount of mercury, usually a few milligrams, so spent or broken CFLs should be recycled at an appropriate drop-off rather than tossed in household trash, and a broken one warrants careful cleanup. LEDs contain no mercury and are recyclable as electronics. On top of that, the far lower energy draw of LEDs and CFLs translates directly into lower carbon emissions over a bulb's life, which is a core reason regulators have pushed the market toward them.

What U.S. Regulations Mean for Buyers

This is the part that has changed most recently, and it directly affects what you can purchase today and in the next few years.

The 2023 incandescent and halogen phase-out

Under a U.S. Department of Energy rule finalized in 2022 and fully enforced from August 1, 2023, general-service light bulbs must produce at least 45 lumens per watt. Standard incandescent bulbs (~15 lm/W) and most halogens can't meet that bar, so manufacturing and selling them is no longer permitted. A handful of specialty types remain exempt, including appliance, bug, plant, colored, and certain shape lamps. Importantly, the rule restricts sale and manufacture, not use: any incandescent or halogen bulbs you already own are perfectly legal to keep using.

The 2028 CFL phase-out

In April 2024 the DOE finalized a stricter standard that raises the minimum to more than 120 lumens per watt, effective July 25, 2028, for newly produced bulbs. Most CFLs fall short of that threshold while a broad range of LEDs clear it easily, so the rule effectively phases CFLs out as well. Several states, including California and Vermont, have moved to restrict CFLs even sooner, largely because of their mercury content.

What this means going forward

The trajectory is unambiguous: the U.S. lighting market is converging on LED. If you're buying or specifying today, choosing LED across the board avoids the cost and hassle of replacing soon-to-be-unavailable technology down the line.

How to Choose the Right Bulb and Switch to LED

For the vast majority of fixtures, the practical question is no longer "which technology" but "which LED." A few quick checks make the swap painless:

• Shop by lumens, not watts. Match the brightness you want, not the old wattage. Our room-by-room lumens guide gives target ranges for each space.
• Match the base and shape. Most household lamps are A19 bulbs, while recessed cans and track heads often use PAR lamps, and older fluorescent fixtures can be retrofitted with LED tube lamps.
• Pick the right color. Choose a Kelvin temperature to suit the room and a CRI of 90+ where color accuracy counts.
• Confirm dimmer compatibility. If the circuit dims, pair the LED with a control rated for LED loads.

Are there cases where another technology still makes sense? Occasionally: an exempt specialty application, an appliance or oven lamp, or a vintage fixture where a warm filament look is the whole point. But for general lighting, LED is the clear, future-proof choice.

Which Bulb Should You Choose?

Incandescent and halogen bulbs gave us a century of warm, accurate light but lose decisively on efficiency, lifespan, and (now) availability. CFLs were a worthwhile bridge yet carry mercury and are on their way out. LEDs lead on virtually every measure that matters and have become the standard the entire U.S. market is moving toward. For new installs, retrofits, and everyday replacements alike, LED is the choice that saves money, lasts longest, and won't be regulated off the shelf.