How many Christmas lights does a house need? Measure every edge you want lit, add about 10 per cent for corners and slack, then divide by the length of one string. A two-storey front 12 metres wide, with a gable and a porch, comes to about 27 metres (89 feet) in the worked example below. Then check the package for how many strings may link together.
In This Article
- How many feet of Christmas lights for a house: measure first
- A worked example for a two-storey Kitchener-Waterloo front
- How long Christmas lights for a house should be: lengths to strings
- How many LED Christmas lights can you string together?
- How many LED Christmas lights on one circuit
- When a crew should measure and install it
- Christmas light quantity questions homeowners ask
How many feet of Christmas lights for a house: measure first
Buy nothing until you have a number. Use a tape or a length of string and write down each edge you want lit, in metres, with the feet in brackets if your packages use feet.
- Straight eaves. Measure along the eavestrough or fascia. From the ground, measure the wall below it, since the roof edge usually matches the wall.
- Sloped edges on gables and peaks. These are longer than the width suggests. Measure half the base of the gable, then multiply by the factor in the table below.
- Corners and returns. Add the short runs where a line turns a corner or wraps a porch.
- Extras. Windows (perimeter is 2 x width plus 2 x height), the door frame, railings, and tree trunks (each wrap is about 3.14 x the trunk width).
The roof pitch is written as rise over run, such as 6/12, which means the roof climbs 6 units for every 12 units across. The sloped edge is that much longer than its horizontal run.
| Roof pitch | Multiply the horizontal run by |
|---|---|
| 4/12 | 1.05 |
| 6/12 | 1.12 |
| 8/12 | 1.20 |
| 10/12 | 1.30 |
Do not climb a roof to measure it. Ground measurements and a rough pitch from your house plans or a photo are close enough. Then add about 10 per cent to the total for corners, small dips between clips and the ends of each string.
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A worked example for a two-storey Kitchener-Waterloo front
Take a made-up but common layout: a house front 12 m (40 ft) wide, a centre gable 5 m wide with a 6/12 pitch, a small porch roof and a short wrap around each corner. These are assumed sizes, so swap in your own.
| Section | Working | Length |
|---|---|---|
| Main eave across the front | Measured straight | 12.0 m |
| Both sloped edges of the gable | 2 x (2.5 m x 1.12) | 5.6 m |
| Porch roof, front edge and two returns | 3.0 m + 1.0 m + 1.0 m | 5.0 m |
| Corner wraps | 1.0 m each side | 2.0 m |
| Subtotal | 24.6 m | |
| Add 10 per cent | 24.6 m x 1.1 | about 27 m (89 ft) |
So this front needs about 27 m of lit line. A shorter bungalow with a plain eave could need half that. A house with several gables, dormers and a garage may need twice as much. Height alone does not add length. It adds edges, because a second storey often means a second row of eave to light.
How long Christmas lights for a house should be: lengths to strings
Now divide your total by the length of the string you plan to buy. Round up, never down, and expect a little spare at the end of each run.
- Mini strings. Natural Resources Canada's own example uses 7.3 m (24 ft) strings. At that length, 27 m needs 4 strings (4 x 7.3 m = 29.2 m).
- Larger bulbs. Check the spacing on the package. If a set has a bulb every 30 cm (12 in), 27 m takes about 90 bulbs.
- Lead wire. The bare cord before the first bulb and after the last one is not lit. Count it when you plan where each plug will reach.
- Net and curtain lights. These are sold by coverage, so measure the shrub or wall in square metres and compare with the label.
- Cut-to-length systems. Commercial roofline lighting is usually made to the measured run, which cuts waste.
Test every string on the ground before it goes up. A dead section found on a ladder costs you a second trip.
How many LED Christmas lights can you string together?
The package decides. Each string lists the most sets that can link end to end, and that number is the one to follow. Mixing brands or types in one chain is not covered by the label.
The Electrical Safety Authority (ESA), Ontario's electrical safety regulator, advises connecting no more than three light strings together. Many LED strings are made to link far more, but only if the package says so. If you cannot find a stated limit, use three.
The limit exists because of the thin wire inside each string. The first set carries the current for every set plugged in after it, and the plug has a small fuse. LEDs draw so little power that the allowed number goes up, but the wire still has a ceiling.
In the worked example, 4 strings would be one run of three plus one single, or two runs of two. Plug each run into its own outlet if the reach allows, and never chain extension cords to stretch a run. Keep plugs and joins off the ground and out of puddles, and use lights rated for outdoor use.
How many LED Christmas lights on one circuit
For LED mini strings, the circuit is rarely the limit. For older incandescent sets, big bulbs and added displays, it can be. The sums are simple. Watts divided by 120 volts gives amps.
A common household circuit is 15 amps at 120 volts, which is 1,800 W. For loads that stay on for hours, a usual rule of thumb in Canadian electrical practice is to stay at or below 80 per cent of the breaker rating. That is 12 A, or 1,440 W, on a 15 A circuit. Outdoor and garage outlets may share a circuit with other things, so add those loads too.
| Load | Watts | Amps |
|---|---|---|
| 4 LED mini strings (about 3.5 W each, from NRCan's example) | 14 W | 0.12 A |
| 90 incandescent bulbs at 7 W each | 630 W | 5.25 A |
| Two runs like that | 1,260 W | 10.5 A |
| Those two runs plus a 300 W motorized display | 1,560 W | 13 A, over the 12 A guide |
NRCan says ENERGY STAR certified LED strings use 75 per cent less energy on average than incandescent ones. That is why the first row is so small. Use the wattage printed on each label, not these figures.
Plug outdoor sets into a GFCI-protected outlet. If a breaker trips, remove some load. Do not fit a bigger breaker. A new outdoor outlet or any hardwired connection is electrical work for a Licensed Electrical Contractor under ESA rules.
When a crew should measure and install it
A measurement is a good DIY job. The climb is not always. A second-storey eave, steep gables and a frosty November morning are the riskiest conditions for ladder work. Keep ladders at least 3 m from overhead power lines and clear of the service mast, and use three points of contact.
If the front is high, complex or both, a company can measure, supply cut-to-length lighting, install it, take it down and store it. D&D Home Services offers holiday lighting from $750 for typical Kitchener-Waterloo homes, covering install, takedown and storage, with the final quote confirmed in writing. For what changes a price, see the Christmas light installation cost guide.
If you would rather not hang anything every year, compare permanent LED lights and seasonal lights. Those systems are measured the same way, one run at a time, and their installation steps start with the same walk around the house.
Christmas light quantity questions homeowners ask
How many feet of Christmas lights do I need for the front of my house?
Add the length of every edge you want lit, then add about 10 per cent. A 12 metre (40 ft) front with a gable and a porch comes to roughly 27 metres (89 ft) in our example. Measure your own eaves, sloped edges and corners, because rooflines vary a lot between houses.
How many LED Christmas lights can you string together?
Follow the maximum printed on the package, which is set by the string's wiring and fuse. ESA advises connecting no more than three strings together. Many LED strings allow more, but only when the label says so. If there is no stated limit, stop at three and start a new run.
How many LED Christmas lights can go on one circuit?
Add the watts on every label, divide by 120 to get amps, and keep long-running loads to about 80 per cent of the breaker rating, which is 12 amps on a 15 amp circuit. LED mini strings use very little power, so older incandescent sets and motorized displays are the usual cause of overloads.
Do I need more lights for a two-storey house?
Usually yes, but not because the house is taller. A second storey adds eaves, gables or window lines you may want to light, and each adds length. Measure each edge you plan to light. Height makes the job riskier on a ladder, so many owners hire a crew for the upper edges.
Key Takeaways
- Measure each lit edge in metres, multiply sloped edges by the pitch factor and add about 10 per cent.
- Divide the total by string length and round up, then test every string on the ground.
- The package sets how many strings link together. ESA's general advice is no more than three.
- Add the label watts, divide by 120 for amps, and keep long-running loads near 12 A on a 15 A circuit.
- A new outdoor outlet is licensed electrical work, and high eaves are often a job for a crew.
Sources & References
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