Household Power Consumption

As we face limits to energy resources and increased greenhouse gases, we have to think more about how to generate clean energy and reduce consumption. For example, replacing a 60-watt incandescent lightbulb with a 12-watt LED saves on energy and cost. But many of us don't know how much energy we use, confused by strange units (e.g., watts and watt-hours).

It's not hard if you think of a 60-watt incandescent bulb lit for 4 hours a night, which thus consumes 240 watt-hours per day (60 W x 4 h) and costs 2.4 cents a day at a typical $0.10/kWh rate. To count your daily power use, fill in the power rating and average time used below for your household appliances/devices and press CALCULATE to see your total power use, percentage, and cost. Our household sample numbers are given as a guide.

E21 Power Counter

The E21 Power Counter calculates average daily household power consumption. In our house, we use roughly 33 kilowatt-hours (kWh) every day or 1,000 kWh per month on average, fairly typical of first-world consumption. And since our utility company charges us about 10 cents per kilowatt-hour, our bill comes to about $100 each month. Fill in your details below (item power rating and time used in minutes) and see what your average daily power consumption is.

Rate($/kWh) Daily consumption:  kWh/day  Amount due:  $/month

ITEM: P (watts) t (minutes) ITEM: P (watts) t (minutes)
Fridge         kWh Microwave         kWh
Oven         kWh Kettle         kWh
Toaster         kWh Dishwasher         kWh
Computer         kWh Printer         kWh
TV         kWh Router         kWh
Stereo         kWh Charger         kWh
Washer         kWh Dryer         kWh
Vacuum         kWh Mower         kWh
Hairdryer         kWh Iron         kWh
Hot water         kWh Radiators         kWh
Heaters         kWh AC         kWh
Dehumidifier         kWh Other         kWh

1. If an appliance shows only voltage (in volts) and current (in amps), the power is the voltage times the current, P = IV.
2. The monthly amount due from daily use assumes 30 days in a month.
3. You will have to do some pre-averaging for some appliances. For example, 2 laundries a week at 90 minutes each is 26 minutes a day. One automatic dishwasher a month at 90 minutes is 3 minutes a day.
4. There is no separate winter/summer use, so prorate heat in winter and AC in summer through the year.
5. I'll add a downloadable Excel file later.

Hopefully, by better understanding how much power we use each day and which items use the most energy, we can help reduce unnecessary consumption. And, hopefully, many of us have already changed those old 60-watt bulbs with modern 12-watt LEDS!

Energy in the 21st Century: Rethink, Rebuild, Rewire -- coming soon

Energy in the 21st Century takes the reader through the history of power generation and the basics of each of the main watershed technologies since the beginning of the Industrial Revolution - wood, coal, oil, gas, nuclear, renewables - and examines the many maturing industries competing for our energy needs today. We have no choice but to find more efficient ways to generate power for heat, electricity, and transportation, recognizing that clean, sustainable energy is the only way forward for a warming planet with finite resources.

About the author

John K. White received a B.Sc. in Applied Physics from the University of Waterloo, Canada, and a Ph.D. from University College Dublin, Ireland.

He has worked around the world as a physicist, lecturer, project manager, and computational analyst over a 25-year career. He has worked as a project manager and technical writer for Sun Microsystems, The Netherlands Organization, and Berminghammer Foundation Equipment, consultant for Interactive Image Technologies, ScotiaBank, and the Ontario Government, and as a lecturer and research fellow at University College Dublin, and has analyzed game playing strategies, from professional sports teams to the stock market as well as many other thought provoking systems.

He is also active in promoting physics and numeracy in schools, and has published widely in academic journals, contributed chapters to edited volumes, and authored numerous technical publications. Born in Dublin, Ireland, he grew up in Toronto, Canada, and now lives and works in Dublin.

Do the Math! On Growth, Greed, and Strategic Thinking

John K. White
Softcover, 350 pages, Sage Publications (2013)

Better numeracy, Do-it-yourself analysis, Social inclusiveness, Foster critical and strategic thinking, Uncomplicated mathematical discussion

Our world has become more complicated, and the notion of growth at any cost has led to constant economic uncertainty, a permanently stressed-out workforce, and everyday stories of government and corporate abuse. John K. White argues that a better knowledge of basic systems is needed to understand the world we live in, from pyramid scams to government bailouts, from sports leagues to stock markets, from the everyday to the seemingly complex.

   John K White