Are LED Christmas Lights Better Than Incandescent for a Roofline?

LED Christmas lights beat incandescent for most outdoor jobs. They use far less power, run cool, resist breakage and let you connect longer runs. Incandescent bulbs still offer a glow some people prefer and often a lower price per string. This guide compares the two on power use, running cost, cold weather, durability and string limits, so you know what to buy or what an installer is quoting.

LED vs incandescent Christmas lights at a glance

The difference that adds up on a house is power draw. It shapes running cost, how long a run you can feed and how much you can plug in without trouble.

Do LED Christmas lights use less electricity? How to work out running cost

Yes. Natural Resources Canada says ENERGY STAR certified LED light strings use 75% less energy on average than conventional incandescent strings, and single-colour LED strings save up to 90%. That is for certified products, so check for the label.

To find what your own lights cost to run, use this:

1. Find the wattage on the package or tag. If only amps are listed, multiply by 120 volts.
2. Multiply watts by the hours the lights are on each night and by the number of nights, then divide by 1,000. The answer is kilowatt-hours.
3. Multiply by your electricity price per kilowatt-hour.

Here is an illustration with made-up round numbers, so use your own labels. Say an incandescent string is rated 40 W and an LED string of the same length is 5 W. Run each for 6 hours a night over 40 nights, which is 240 hours. The incandescent string uses 9.6 kWh and the LED string uses 1.2 kWh. Whatever your rate is, the LED string costs one-eighth as much.

Ontario rates depend on your plan. Time-of-use, tiered and overnight plans price electricity differently, so look at your bill and check which price period your lighting hours fall into. A timer or photocell that limits the hours does as much as the bulb type.

How many strings can run together on a long roofline

Every string has a label that states how many sets you may connect end to end. That label is the limit, and you should not exceed it. The Electrical Safety Authority's holiday guidance advises connecting no more than three light strings together. Many LED strings are labelled for longer chains because each draws so little current, but follow the package, not a guess.

Do not mix LED and incandescent strings in one connected chain unless the label allows it. Their ratings differ.

The circuit is the second limit. A typical outdoor outlet shares a 15-amp circuit with other outlets, and at 120 volts that circuit is rated for 1,800 watts. A common rule of thumb keeps long-running loads to about 80% of that, or 1,440 watts, and the other outlets on the circuit use some of it too. Twenty incandescent strings at 40 W each is 800 W, more than half the allowance. Twenty LED strings at 5 W is 100 W.

For a long roofline, plan zones. Each zone gets its own plug and stays within its label limit. Use outdoor-rated cords and plug into a GFCI-protected outlet. If the roofline needs more power than an outlet can give, or there is no outdoor outlet, adding one is electrical work that Ontario assigns to a Licensed Electrical Contractor under ESA rules. Do not run a cord through a closed door or window instead.

Cold weather, breakage and lifespan outdoors

Natural Resources Canada reports that certified LED strings last up to 10 times longer than incandescent ones and are more durable and shock-resistant. Outdoors in Ontario, that means fewer dead bulbs to chase on a cold ladder in December.

Cold affects every cord. Insulation stiffens below freezing, and sharp bends can crack it. Unroll and test strings indoors, lay them out in a warm space, and handle them gently when you hang them. Buy lights rated for outdoor use and look for a recognized certification mark on the package.

Incandescent bulbs have a few extra weak points. Glass bulbs break when dropped or knocked by wind, and a dead bulb in some series-wired strings can darken a section. They also give off heat, which keeps clips and cords warm, so check that nothing is touching dry material.

LEDs have one quirk outdoors. Because they stay cool, wet snow and ice can sit on the bulbs and dim them. Let the snow melt or slide off on its own, and do not chip ice off or tug on the cords.

Brightness, colour and the look of the house

Incandescent bulbs give a warm, slightly yellow glow that many people remember. LEDs come in several whites, from warm to cool, as well as in colours, and descriptions vary between brands. A string sold as warm white may not match the one you bought last year.

Buy one string first and look at it after dark before you commit to a whole roofline. Check it against your existing strings if you are adding to a display, and make sure all strings on one run are the same type so the colour matches.

If you want dimming or colour effects, confirm the controller is made for the lights you chose. Not every dimmer works with every LED string.

Which should you choose? Decision rules

Choose LED if:

• You are lighting a long roofline or several rows.
• The lights stay on for many hours or many weeks.
• The eaves are high and you want to avoid replacement trips.
• You are limited by the outlet or circuit.

Incandescent can still make sense if:

• The display is small and you already own good strings.
• You want the classic glow and accept the higher draw.

If a company is quoting a job, ask whether it uses LED or incandescent, how many strings run on each plug and how it handles power. Our guide to Christmas light installation costs in Ontario shows what else shapes a quote. Permanent roofline systems are built on LEDs, and we compare them with seasonal strings in permanent LED lights versus seasonal lights.

D&D Home Services does seasonal installs, takedown and storage from $750 for typical Kitchener-Waterloo homes. See the holiday lighting page for details.

LED and incandescent Christmas light questions

Are LED Christmas lights better than incandescent?

For most outdoor uses, yes. LEDs draw far less power, stay cool, break less often and allow longer chains on one outlet. Incandescent lights can still suit a small display where you want a classic glow or already own good strings. For a long roofline the lower power draw usually decides it.

Do LED Christmas lights use less electricity?

Yes. Natural Resources Canada says ENERGY STAR certified LED light strings use 75% less energy on average than incandescent strings, and single-colour strings use up to 90% less. Your own saving depends on the labelled wattage of the lights you compare and on how many hours they run each night.

Do LED Christmas lights last longer than incandescent?

Yes. Natural Resources Canada reports that ENERGY STAR certified LED strings last up to 10 times longer. They also tend to survive handling and wind better because they do not rely on a fragile filament in a glass bulb. A cheap string without certification may not match that, so check the package.

How much do LED Christmas lights cost to run?

Multiply the labelled watts by hours of use and divide by 1,000 to get kilowatt-hours, then multiply by your electricity price per kilowatt-hour from your bill. An LED string usually costs a fraction of an incandescent string to run, and a timer that cuts the hours lowers the cost further.

Can I mix LED and incandescent strings on one chain?

Do not, unless the label says it is allowed. LED and incandescent strings draw different amounts of current, and the connection limits on each package assume strings of that type. Run each type on its own chain, and keep every chain within the number of strings the label permits.

Devon Moore, Operations Lead Co-Founder & Operations Lead, D&D Home Services

Devon Moore is the co-founder and Operations Lead at D&D Home Services, with hands-on experience cleaning hundreds of homes across Kitchener-Waterloo, Cambridge, and Guelph.