There is a ritual in many households that begins with a tangle. A box of Christmas lights comes down from the attic, the strands have knotted themselves over eleven months in the dark and one in three refuses to light. People fight with them, replace a few bulbs, give up and drive to the store for new ones. At the shelf, they meet the question that has divided lighting aisles for years: LED or incandescent?
The answer has shifted over the last decade. LEDs, once expensive and cold-looking, now match the warm glow of the old bulbs, last far longer and use a small fraction of the electricity. But incandescent lights have not disappeared, and they still have a place. This guide explains how the two technologies differ, what that means for how many strands you can run, how to compare brightness and color and how to choose bulbs for the indoor and outdoor places where you will use them. It is general information, and the manufacturer’s ratings and instructions take priority. We do not give electrical installation advice.
In brief
- LEDs use a fraction of the power and run many more strands per circuit.
- Check the outdoor rating and the maximum connected strands.
- Warm-white LEDs can match the old glow, but test before mixing.
- Buy certified products and never exceed the ratings.
How the bulbs work
An bulb has a thin filament that glows when electricity heats it. The warm, slightly yellow light is familiar. The filament wastes most of the energy as heat, which is why the bulbs are warm to the touch and why a long run of strands draws a lot of power.
An bulb produces light by passing current through a semiconductor. It makes little heat, uses far less energy and can be made in many colors and shapes.
Power use and what it means for your circuit
This is the most practical difference. Incandescent mini lights typically draw several times as much power per strand as LEDs. That limits how many strands you can connect end to end and how many you can run on one circuit.
Manufacturers print the maximum number of strands that may be connected end to end, along with the wattage or amperage, on the packaging or the plug. Do not exceed it. Overloading a strand or a circuit can cause overheating, blown fuses or fires. Extension cords and outlets also have limits, which are marked on them. Follow the ratings. If you are unsure about the capacity of a circuit, ask a licensed electrician.
Comparison
| Factor | Incandescent | LED |
|---|---|---|
| Power use | High | Low |
| Heat | Warm to hot | Cool |
| Lifespan | Shorter, bulbs burn out | Much longer |
| Durability | Glass bulbs break more easily | Often plastic or tougher |
| Strands per circuit | Few | Many more |
| Light color | Warm, with soft glow | Warm white, cool white and many colors |
| Dimming | Naturally dims | Depends on the product |
| Upfront cost | Lower | Higher, but falling |
| Running cost | Higher | Lower |
Brightness and color
Brightness is measured in lumens, though many holiday lights do not list them. Bulb count and size give a rough guide. LEDs often look brighter than incandescent bulbs of the same wattage, because they are more efficient.
Color is described in two ways. For white lights, the color temperature, in kelvins, ranges from warm (around 2,700 K, similar to the traditional glow) to cool white (above 5,000 K, bluish). For colored lights, check whether the color is produced by the LED itself or by a colored coating, which can fade.
Many people find that the warm white LEDs that mimic an incandescent glow are the most pleasing, but this is a matter of taste. Some LEDs look harsh next to older strands, so avoid mixing types in the same display without testing.
Bulb shapes and sizes
- are the small bulbs on thin wire, used on trees and wreaths.
- are larger, cone-shaped bulbs, often used on rooflines and outdoors.
- are bigger still, for traditional roofline displays.
- are round and used for a modern look.
- are designed for eaves and shrubs.
- are flexible tubes for outlining.
- use thin copper wire with tiny bulbs, often battery powered.
Choose the shape for where you will use it. Bigger bulbs are visible from the street, while mini lights suit trees.
Indoor versus outdoor ratings
Look for a rating that says the product is suitable for outdoor use. Outdoor lights are built to resist moisture and temperature changes. Indoor lights used outdoors can short, fail or become a hazard. Check the packaging and the markings on the plug and the cord.
- with outdoor lights, and keep connections off the ground and out of puddles, using covers designed for the purpose.
- if available. We do not give installation instructions. If you do not have an outdoor outlet with the right protection, ask a licensed electrician.
- or under rugs.
Safety certifications
Look for a recognized safety certification mark on the packaging. It indicates that the product has been tested to a standard. Avoid uncertified lights, and do not use damaged strands with frayed wire, cracked sockets or exposed copper. Replace them.
Replaceable bulbs and fuses
Some strands have replaceable bulbs and fuses in the plug, and others do not. Replaceable bulbs allow repairs when one burns out, though matching the replacement bulb to the strand matters. A replacement of the wrong rating can overload the strand. Keep spare bulbs and fuses as supplied. Many LED strands are sealed and cannot be repaired. Check what you are buying.
Cost over time
LED strands cost more to buy, and they save money in the long run through lower electricity use and longer life. The savings depend on how many strands you run and for how many hours. Even for a modest display, the difference can be noticeable on the electric bill, and for a large display it can be substantial. We do not quote prices, which vary.
Special features
- can be controlled with a remote or an app.
- turn lights on and off automatically. Check the rating of the plug.
- can suit small outdoor areas, but they may be dim in winter.
- suit places without outlets, but batteries run down.
Features add cost and complexity, and consider whether you will actually use them.
How many strands do I need?
A rough guide for mini lights on a tree is about 100 lights per foot of tree height for a full look, with more or fewer to taste. For rooflines, measure the length in feet, and compare with the strand length. Our guide to planning an outdoor light display explains how to measure and plan, and our guide to choosing an artificial tree covers pre-lit options.
Care and storage
Handle strands gently, and store them on a spool, a reel or around a piece of cardboard so they do not tangle. Test them before hanging, and replace faulty ones. Our guide to storing decorations offers more tips.
Choosing: a short guide
- LED mini lights in your preferred white or color, with a certification mark.
- outdoor-rated LED C7 or C9 or icicle lights, with a total load within the ratings.
- warm-white LEDs designed to resemble incandescent bulbs, or incandescent if you accept the higher power use.
- LEDs, for the power savings and the ability to connect more strands.
The short version
LED lights use a fraction of the power, last much longer and allow more strands per circuit, while incandescent lights offer the traditional glow at a higher energy cost. Choose by where you will use them, check the outdoor rating and the maximum strand connections, buy certified products and never exceed the ratings. A little attention to power and safety makes for a good-looking, trouble-free display.
What to do next
- Decide where each strand will go.
- Check indoor or outdoor rating on the pack.
- Add up the wattage per circuit and cord.
- Test every strand on the ground before hanging.
- Keep spare bulbs and fuses with each strand.
