Christmas light bulbs come in two large sizes. The C7 is 2 inches tall on an E12 candelabra base, a finer scale best for displays viewed up close; the C9 is 3 inches tall on an E17 intermediate base, best for displays that stand out from a greater distance. Both come in LED and incandescent, in a wide range of colors and finishes.
Kringle Traditions® vs OptiCore® vs FlexFilament®
For quality C7 and C9 Christmas lights on a budget, Kringle Traditions® bulbs offer loads of upgrades over the bulbs you'll find at big box stores. Shatterproof lenses provide durability, SMD LED technology provides brightness, and diamond-faceted lenses provide the sparkle. Available in ten colors, these are bulbs you can enjoy year after year.
If you're looking for the gold standard in Christmas light bulbs, you've found them. OptiCore® C7 and C9 Christmas lights from Wintergreen Lighting® feature thick polycarbonate lenses that not only make them shatterproof, but give them a magical glow as the light from inside the bulb resonates through the lens. Available in diamond-faceted or smooth opaque lens styles, in a wide variety of colors and color combinations, and in both C9 or C7 Christmas lights, these bulbs are designed to take the worst that winter can throw at them, and keep shining beautifully
Vintage-style Edison bulbs evoke a special kind of Christmas nostalgia. FlexFilament® Christmas light bulbs from Wintergreen Lighting® feature graceful, curved filaments lined with LED diodes, to give you a bulb packed with old-world charm, and all the advantages of modern LEDs. Available in glass or lightweight, shatterproof PolyFlex PET, the transparent lens on these bulbs lets the beauty of the visible filament shine right through.
C7 vs C9 Christmas Light Bulbs
C7 and C9 are the two large Christmas bulbs; they differ in scale and base. The C7 is the smaller cone-shaped bulb at 2 inches tall from base-to-tip — a finer scale that shows well where a display is viewed up close. That suits railings, window and door frames, mantels and small Christmas trees, and homes with less exterior footprint like condos and townhomes. C7 bulbs use an E12 candelabra screw base, so they drop straight into matching C7 socket wire.
The C9 is the larger cone-shaped bulb at 3 inches tall from base-to-tip — 50% taller than the 2-inch C7 so it stands out from a greater distance. That makes it the standard choice for rooflines, driveways, large Christmas trees, and other outdoor displays that need to look great from the street. C9 bulbs use an E17 intermediate screw base, so they drop straight into matching C9 socket wire.
Both fit C-series stringers with matching sockets, but the two are not interchangeable: a C7 won't seat in a C9 socket, and vice versa, so match your bulbs to your sockets before you buy. Shop C7 bulbs and C9 bulbs.
LED vs. Incandescent Christmas Light Bulbs
C7 and C9 bulbs are available in either LED or incandescent, and the choice comes down to what you want from the display.
LED bulbs are rated from 20,000 to 60,000 hours with no filament to burn out, which means the same bulbs light your display season after season. An LED bulb draws under a watt, 90% less than the 7-watt C9 incandescent it replaces so you can safely run longer lines of light. They stay cool to the touch making it safe for pets, kids, wreaths, garland and Christmas trees. LED bulbs are dimmable for full control of the look and work great in steady or animated displays (sold separately).
Our LED C7 and C9 bulbs span three lines. OptiCore® is the professional-grade bulb the pros use because it is built for commercial displays and anyone who wants a professional result at home. On FlexFilament®, a curved LED filament glows through the lens like an antique Edison bulb, giving your display old-world character with modern LED efficiency. On Kringle Traditions®, shatter-resistant polystyrene means the bulb survives on the roofline and the storage bin with color that never fades, chips or cracks.
Incandescent bulbs produce the classic glow of a traditional Christmas, giving you the look that has lit displays for generations. Incandescent bulbs carry the lowest initial cost per bulb, so you can light a full display for less at the start. C7 bulbs come in 5 watt (plus a 7 watt option available in clear); C9 bulbs in 7 watt (plus a 10 watt option available in clear), so you can pick brighter bulbs or more of them on a single line of light. Commercial Grade bulbs rated for an average life of 3,000 hours light six seasons of nightly use, so you replace fewer bulbs over the life of a display.
On both, nickel-plated bases resist corrosion and connect cleanly, saving you time and hassle every season, and bulbs are rated for indoor and outdoor use, so one string works anywhere you install it.
As a rule of thumb, choose LED for larger and long-term displays, and incandescent when lowest initial cost is priority one.
Vintage & Retro Christmas Light Bulbs
If you want a traditional, old-fashioned Christmas look, you have three options.
FlexFilament® is Wintergreen Lighting's vintage Edison-style LED line. A curved LED filament glows through the lens like an antique Edison bulb, giving your display old-world character with modern LED efficiency, and a transparent lens leaves the curved filament in full view. The bulbs use lightweight PolyFlex PET for worry-free, shatterproof bulbs, with select products available with a satin glass lens for a true vintage look.
OptiCore® offers a traditional smooth opaque finish alongside its diamond-faceted one. That is the finish to reach for when you want the classic look in a durable LED.
Incandescent bulbs produce the classic glow of a traditional Christmas, giving you the look that has lit displays for generations, and they carry the lowest initial cost per bulb, so you can light a full display for less at the start.
Choose FlexFilament® for the Edison-filament look, smooth opaque OptiCore® for the traditional look, both in durable LED, or incandescent for the classic glow at the lowest initial cost.
Choosing Color, Finish, and Light Display
C7 and C9 bulbs come in a wide range of colors. On OptiCore®, ten color options including a 3000K warm white give you the full palette for traditional and modern displays alike. On Kringle Traditions®, ten colors cover the classic Christmas palette plus the shades most sets leave out, allowing you to match any display. On FlexFilament®, eight colors give you range across warm vintage tones and true Christmas color. Available in red, green, blue, white, clear and other colors, incandescent bulbs give you the traditional Christmas palette to build a display around. Triple-dipped color goes on the transparent bulbs in three passes, resisting fading and cracking for rich color that lasts.
Finish is how the bulb's lens interacts with the light. OptiCore® bulbs come in diamond-faceted and traditional smooth opaque finishes, allowing you to match the bulb to the look you are building. On Kringle Traditions®, diamond-faceted bulb designs reflect a spectacular light and color halo that carries from a distance. On FlexFilament®, a transparent lens leaves the curved filament in full view, and a satin finished glass lens softens the filament into an even, candle-like glow. On incandescent, transparent bulbs show the filament, while opaque finishes diffuse the light into a soft, even glow.
Light display is another choice point. On LED, steady and twinkle versions come in the same finishes, so you can add movement without changing the look of the bulb. On incandescent, twinkle bulbs pulse on and off at random, adding movement to a display that would otherwise sit steady.
Pro Tip:
Pro Tip: Match the bulb to your socket before you buy. C7 bulbs use an E12 candelabra screw base and C9 bulbs use an E17 intermediate screw base; the two don't interchange — a C7 bulb won't fit a C9 socket, or the reverse. If you're replacing bulbs on an existing display, check the base size before ordering. You can mix colors and finishes on one string if you like, but the base sizes must match.
Frequently Asked Questions:
What are the different types of Christmas light bulbs? Christmas light bulbs come in two large sizes, C7 and C9, and two technologies, LED and incandescent. LED bulbs are rated from 20,000 to 60,000 hours with no filament to burn out, which means the same bulbs light your display season after season. Incandescent bulbs produce the classic glow of a traditional Christmas and carry the lowest initial cost per bulb. Both come in a variety of colors and finishes.
What is the difference between C7 and C9 Christmas light bulbs? The C7 is the smaller cone-shaped bulb at 2 inches tall from base-to-tip, a finer scale that shows well where a display is viewed up close. The C9 is the larger cone-shaped bulb at 3 inches tall from base-to-tip, 50% taller than the 2-inch C7 so it stands out from a greater distance. C7 bulbs use an E12 candelabra screw base and C9 bulbs use an E17 intermediate screw base, so the two are not interchangeable in the same socket.
What is the largest Christmas light bulb? Among standard Christmas light bulbs, C9 is the largest common size, 3 inches tall from base-to-tip and 50% taller than the 2-inch C7, so it stands out from a greater distance. Both are much larger than mini lights, which is why C7 and C9 bulbs are the choice for rooflines, driveways and displays seen from a distance.
Will your C bulbs fit my stringer? Yes, as long as you match bulb size to your stringer socket size. C7 bulbs use an E12 candelabra screw base, so they drop straight into matching C7 socket wire; C9 bulbs use an E17 intermediate screw base, so they drop straight into matching C9 socket wire. They are not interchangeable: a C7 bulb won't screw into a C9 socket, or vice versa. Before ordering replacement bulbs, check the base on your existing stringer or an old bulb so the new bulbs fit.
