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Backyard Review

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How many holiday lights do I need?

Measure the roofline, count the windows and trees, and get a shopping list with the circuit load checked, so you do not trip a breaker on the first night.

What are you lighting?

ft
ft
ft

A 3 × 4 ft window is 14 ft.

ft

About 2 strands each.

ft

What lights?

Bulb technology

Roofline style

Edit strand length and wattage

These are typical values. Use the numbers printed on your strand or box.

LED mini

LED C9

Printed on the box. Many incandescent sets allow only about 3 to 5; many LED sets allow far more.

$/kWh

Example value. Use the rate on your bill.

Strands to buy

22

6 mini + 16 mini for trees and shrubs

Season running cost

$4.49

26 kWh at 6 h × 40 nights

Total load

110 W

0.9 amps at 120 V

Plug points to plan

5

1 circuit suggested

Circuit load

110 W of a safe 1,440 W continuous limit (8%) on a 15-amp circuit.

Comfortable headroom on a single circuit, as long as little else shares it.

Shopping list

  • 6 × LED mini strands (about 144 ft of roofline, windows, rails and fence, with 10% to spare)
  • 16 × mini strands for 2 trees and 4 shrubs
  • 5 outdoor-rated extension cords and a GFCI-protected outlet or adapter for each run
  • 1 or 2 outdoor timers or smart plugs so lights switch off on schedule
  • Insulated clips for gutters and eaves (never staples or nails through the wire)
How this is calculated

Linear feet = roofline × 1.1 + window edges + rails × 1.1 + fence × 1.1; the extra 10% covers corners and sag. Strands = feet ÷ strand length, rounded up. Trees use one mini strand per 6 ft, 3 ft or 1 ft of height depending on how dense you want them, the last matching the common rule of about 100 lights per foot of tree.

Load = watts per strand × strands. Amps = watts ÷ 120 V. A circuit should carry no more than 80% of its rating for continuous loads such as holiday lights, so a 15-amp circuit tops out at 1,440 W and a 20-amp circuit at 1,920 W. Cost = kWh × your rate.

Strand length, wattage and link limits come from the label, not from us. Use outdoor-rated lights and cords, plug into GFCI-protected outlets, keep cords out of standing water, and stay well away from power lines when using a ladder.

Keep going

Quick answers

How many Christmas lights do I need for my house?

Measure the roofline and any other edges you want to outline, add about 10 percent for corners and sag, and divide by the length of one strand. A typical LED or incandescent strand runs around 20 to 25 feet, but check the box for the real length.

How many lights do I need for a tree?

A common rule is about 100 mini lights per foot of tree height for a fully lit tree, so a 6-foot tree takes roughly 600 lights. For trunk-and-branch wraps on outdoor trees, plan about one strand per three feet of height.

How many strands can I connect together?

Whatever the box says. Many incandescent strands can be linked only about three to five at a time, while many LED strands can be linked far more. Going past the printed limit can blow a fuse or overheat the wire.

How much power can one outlet or circuit handle?

A 15-amp circuit is rated for 1,800 watts, but for continuous loads like holiday lights you should stay at 80 percent of that, or 1,440 watts. A 20-amp circuit allows 1,920 watts. Other things on the same circuit count toward the total.

Are LED holiday lights worth it?

For most people, yes. They draw a small fraction of the power of incandescent strands, run cool, and let you link far more together, which cuts the number of outlets and the load on your circuits.

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