Halloween Display Wattage Calculator
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Inflatables plus light strands → total watts and whether one 15-amp circuit is enough at 80% safety load.
Display load
Total display load
850 W
Fits one 15 A circuit (80% load)
- Total watts
- 850 W
- Max per circuit (80%)
- 1,440 W
- Fits one circuit
- Yes
- Circuits suggested
- 1
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Halloween décor electrical load
Outdoor Halloween displays stack inflatables, projector bulbs, and LED or incandescent strings on the same garage or porch circuit. This calculator sums inflatable count × watts each plus strand count × watts per strand, then compares the total to a typical 120 V circuit at your chosen amperage with an 80% continuous-load safety factor.
US residential circuits are often 15 A (sometimes 20 A for dedicated outdoor receptacles). At 15 A and 120 V with 80% headroom, plan roughly 1,440 W before tripping breakers or overheating extension cords — not the full 1,800 W nameplate.
Example: three inflatables at 150 W each plus ten light strands at 40 W each totals 850 W — fits one circuit with margin. Three inflatables at 150 W plus ten strands at 40 W on a single 15 A line is comfortable; adding a fourth 150 W inflatable and more incandescent strands can push past one circuit.
LED strands draw far less than vintage incandescent — update watts-per-strand to match your box label. Inflatables spike briefly at startup when compressors kick — stagger timers if breakers nuisance-trip at dusk.
Use outdoor-rated cords and GFCI-protected outlets; keep connections off wet ground. This tool does not model voltage drop on long cheap cords.
Split loads across left and right porch circuits when possible — map breakers before Black Friday inflatable season sales.
Limits: planning math only — not an electrical inspection. Consult a licensed electrician for permanent install or if breakers trip repeatedly.
Common questions
Why use 80% of circuit amperage?
Continuous loads (lights and inflatables running for hours) should stay below 80% of breaker rating to reduce heat buildup — a common NEC planning guideline for homeowners.
Where do I find watts per strand?
Check the product box or tag — LED sets may be under 10 W; incandescent mini-lights are often 40–50 W per short strand.
What if I need more than one circuit?
Run separate outdoor-rated extension cords to different receptacles on different breakers. Avoid daisy-chaining many high-watt inflatables on one cord.