The holiday season is upon us, and decorating our homes with festive lights is a beloved tradition. From simple tree lights to extravagant displays, the type of bulbs we choose can have a significant impact on our electric bill. In fact, a recent survey found that Americans spend an average of $384 on outdoor holiday light decorations, excluding the cost of electricity. But fear not, there's a simple way to determine how much your light display will affect your electric bill.

The Formula

Before purchasing your lights, you'll want to find the wattage of the strand. This information is usually printed on the box or available in the specifications section if you're buying online. Once you have the wattage, use the following formula:

1. Multiply the wattage by the number of hours the lights will be on each day, then divide by 1,000 to find kilowatt-hours (kWh) per day.
2. Multiply the kWh per day by the cost of power usage (found on your electric bill) to find the cost per day.
3. Multiply the cost per day by the number of days your lights will be on.

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Comparing Different Light Styles

To give you an idea of the cost differences between different light styles, here are some comparisons based on LED and incandescent bulbs. For these comparisons, we'll assume six hours of usage per day over 30 days.

• A strand of 300 white mini LED lights on a typical green wire consumes 21 watts, while the same style with incandescent bulbs consumes 72 watts. Using the national average cost of 16.29 cents per kWh and the specified usage, the LED lights will cost about 62 cents, whereas incandescent lights will cost about $2.11.
• For a strand of 100-light C9 LED lights consuming 4.8 watts, the cost would be approximately 14 cents. In contrast, a 25-light strand of C9 incandescent lights consuming 175 watts would cost about $5.13. Similarly, a 25-light LED C7 strand using 21 watts would cost about 62 cents, whereas the incandescent version using 125 watts would cost approximately $3.67.

Remember, these costs are for a single strand of lights. To determine the overall cost of your display, multiply the above values by the number of strands you plan to use.

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Variation in Cost

It's important to note that the total cost of powering your lights depends on the local electricity rates. For instance, residents in Hawaii, where the average cost is 41.52 cents per kWh, could expect costs ranging from 36 cents to $9.34 for the same light styles mentioned above. On the other hand, those in Washington, with a rate of 11.38 cents per kWh, would pay between 10 cents and $3.60.

In Illinois, the average residential price is 14.79 cents per kWh. Using this rate, the costs for the mentioned light styles would range from about 12 cents to $4.66.

LED vs. Incandescent

While LED light strands may have a higher upfront cost (ranging from $32 to $80 compared to incandescent strands that range from $13 to $28), they are more cost-effective in the long run. Incandescent lights will put a greater strain on your electric bill over time.

The Cost of Clark Griswold's Lights

If we were to calculate the cost of Clark Griswold's iconic light display from the movie "National Lampoon's Christmas Vacation," using the data from Illinois where the film was set, here's what we would find. Assuming he used a set of white incandescent string lights with 25,000 bulbs, he would need 1,000 strands. Using the formula above, the display would cost him around $186.30 after a month. However, if he opted for a similar set of LED lights, he would only need 250 strands, costing him approximately $31.93.

Regardless, neither option would make the outlet look any less overwhelming.

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Frequently Asked Questions

Q: Can I use the same formula for calculating the cost of other electrical devices?

A: Yes, you can use the same formula to estimate the cost of powering any electrical device by knowing its wattage and the duration of usage.

Q: Are LED lights more energy-efficient than incandescent lights?

A: Yes, LED lights consume less energy than incandescent lights, making them more energy-efficient and cost-effective in the long run.

Q: How can I reduce the electricity cost of my holiday light display?

A: To reduce electricity costs, consider using LED lights instead of incandescent lights, limit the hours of usage, and make sure to turn off the lights when not needed.

Q: Should I consider solar-powered lights to save on electricity costs?

A: Yes, solar-powered lights can help you save on electricity costs. They harness energy from the sun during the day and illuminate your display at night without using electricity from the grid.

Q: Are there any other factors I should consider when calculating the cost of my light display?

A: Other factors to consider include local electricity rates, the number of strands used, and the duration of your light display. These variables will impact the overall cost.