We’ve tried to calculate how much sweat and human effort it would take to charge a smartphone, brew a pot of coffee and even power a refrigerator. But this whole time, we’ve been making grownups do all the work. What better time than Halloween to let the kids carry their share of the load?

Many homeowners go all-out to make their homes and lawns as spooky as possible for Halloween night, and we wondered what kind of effort it would take to keep that atmosphere going using nothing but the power of trick-or-treating.

How Much Electricity Do Halloween Decorations Use?

For our experiment, we picked a few classic Halloween decorations: LED string lights, inflatable lawn decorations and a fog machine.

As you may know, LEDs are extremely energy-efficient. A typical string of 70 bright LEDs comes in at just under five watts, so you can line your gutters and snake them through your hedges without a worry as to what it will cost you — though you might feel differently when the only way to light them up is to trick-or-treat til’ the cows come home. Let’s string up eight of them for our experiment.

Most lawn inflatables run on small air pumps, of which the wattages vary. We turned to yardinflatablelife.com for some estimates and found that a six-foot inflatable consumes about 60 watts. That’s not much, so let’s use two of them.

The fog machine — that’s the powerhouse. It may be small in size, but this model takes 400 watts to cast our lawn in a creepy mist.

Add it all up, and it will take about 560 watts to keep our house spooktacular. Let’s go easy on the kids and only make them power these decorations for three hours, long enough to distribute all our candy.

How Many Calories Will It Take?

Regardless of whether it’s the kids or their parents doing the sweating, one energy conversion remains the same: one calorie is the equivalent of 4.1868 watt-seconds, with a watt-second being the amount of energy required to sustain one watt for one second.

So let’s see how many calories worth of energy it would take to keep all 560 watts of eeriness going for one second:

560 watts ÷ 4.1868 watt-seconds = 133.753702111 calories per second

Just How Much Trick or Treating Are We Talking About Here?

To complete our calculations, we’ll need to standardize a few things. The Compendium of Physical Activities lists the standardized energy expenditures of various activities, which are expressed in terms of METs (metabolic equivalents). There’s no entry for trick-or-treating, unfortunately, but there is an entry for walking while carrying a 15-pound load. Since our kids will be schlepping around a costume, a flashlight and a big bag of candy, we’ll estimate 15 pounds as about right. This activity generates 5 METs.

We can’t do the math without knowing how much our trick-or-treaters weigh, so we turned to some charts from the Centers for Disease Control and Prevention for estimates. Let’s choose a ten-year-old boy and a ten-year-old girl, each at the 50th percentile for weight. That gives us a boy weighing about 30 kg and a girl who weighs about 35 kg.

So how many calories per hour can these kids expect to burn while walking house-to-house?

5 METs x 30 kg = 150 calories per hour for boys

5 METs x 35 kg = 175 calories per hour for girls

Now let’s see how many calories they’ll have to metabolize to keep the lights on and the fog flowing for the full three hours. Remember, it takes 133.753702111 calories per second, and there are 10,800 seconds in three hours.

10,800 seconds x 133.753702111 calories per second = 1,444,539.9828 calories total

That’s a lot of calories! In trick-or-treating terms, that’s equivalent to:

• 13,132 Reese’s Peanut Butter Cups

• 16,995 Fun Size Butterfingers

• 18,057 Fun Size Twix

• 20,636 Fun Size Kit Kats
• 24, 076 Fun Size Nestle Crunch Bars

So to hit that not-so-fun-size calorie total, our ten-year-old boy will have to trick-or-treat for 401 days, 6 hours, 15 minutes and 59 seconds to round out three hours of front lawn scary-time.

And because girls mature faster than boys, our ten-year-old girl will get the job done in a mere 343 days, 22 hours, 30 minutes and 51 seconds.

Better stretch first, kids. Have fun out there and be safe!