Getting a sense of energy

Growing up, my parents drilled to my bones that energy should never be wasted. Turn off the lights, the AC. I became afraid of using, imagining the smokestacks and polar bears.

But today I finally decided to take a look.

US average electricity price is 0.18/kWh(€0.29 0.18/kWh (€0.29~0.31/kWh in the EU, ~0.35/kWh,Massachusetts 0.35/kWh, Massachusetts ~0.29/kWh); ad. Or 16 cents for using an appliance that runs at 1000 watts for an hour.

A typical light bulb now runs at 10W (the “60W” means it shines as bright as old 60W bulbs), so that’s 0.16/1000W∗hour∗10W=0.16/1000W*hour * 10W = 0.0016 per hour.

For 12 hours a day, thats 0.0016∗12=0.0016*12=0.0192 (2 cents!) per day, and 0.0192∗365=0.0192*365=7.01 per year.

Should save for sure, but not panic-worthy.

Let’s get a sense of perspective

Humans

1 Calorie (on food labels) = 1000 cal (heat to raise 1g of water by 1° C) = 1kcal \approx 4000 J

What are we actually limited by? Not caloric energy, so brain chemicals?