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Electricity at Home: from the Power Plant to Your Socket · EPISODE 4 · 2:37

Your Bill — Watts, Hours and kWh

A phone charger left plugged in for TEN years uses about as much energy as a heater for ONE evening. So what really costs you money? Watts vs kilowatt-hours, how to read your electricity meter, and the appliances that are the real big spenders — explained simply. Episode 4 of Electricity at Home, in under 3 minutes.

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What you'll learn

  • Watts = how fast something uses energy: a heater ≈ 2,000 W, an LED bulb ≈ 10 W.
  • Your bill charges for energy = watts × hours. 1,000 W for 1 hour = 1 kWh = one "unit" on your bill.
  • A 2,000 W heater for 1 hour = 2 kWh; a 10 W bulb needs 200 hours to use the same.
  • Your meter is a counter that adds up every kWh. Read it today and again in a month; the difference is what you pay for. The pulse light blinks for every tiny bit of energy (e.g. 1,000 blinks = 1 kWh) — faster blinks = more power now.
  • In a month: a kettle 3 times a day ≈ 9 kWh, an LED bulb 5 h a day ≈ 1.5 kWh, a charger left plugged in ≈ 0.07 kWh.
  • The big spenders are things that make heat or cold: heaters, air conditioners, water heaters, ovens, dryers. A charger or a TV on standby usually costs less than $1 a year.
  • Cost = watts × hours ÷ 1,000 × your price per kWh (prices vary a lot by country).
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Quick refreshers

EP.47 · Home Electrical · 6What is 1 unit of electricity? (kWh) MYTH EP.74 · Myth or FactMyth or Fact: "A TV on standby uses no power" EP.90 · QuizQuiz #5: A 1000 W heater runs 3 hours — how many kWh? MOSTLY MYTH EP.153 · Myth or FactMyth or Fact #12: "A charger left in the socket wastes lots of power" — MOSTLY MYTH EP.199 · Home Electrical · 11Home Electrical Part 11: smart meters — how your meter talks to the power company EP.242 · Home Electrical · 12Home Electrical Part 12: time-of-use — why evening power costs more