Thursday, May 22, 2008

Energy consumption of a cable box

Or another reason to dislike your cable company

Abstract: Cable TV box apperently responcible for 1% of my entire household energy consumption.

I recently bought Energy Meter - the device you can plug between electrical/hydro outlet and your appliances and it shows you exactly how much power this or that device/appliance consumes. Not that I'm too concerned about my hydro bill, I'm paying about $100/month for a big house with 6 people living in. Wouldn't call it a unreasonable bill.

So it's more about curiosity. Tried simple things - my laptop - 50 Watts. Desktop lamp with Energy efficient bulb – 9 Watt. Microwave Oven 1475 Watts!!! Scary, but you run it few minutes a day. TV – 50-70 Watts depending on volume level.

How does all that translates into the electricity bill I got at the end of the month? Relatively simple. What you pay for is kWh – or Kilo Watt Hour. Kilo stands for one thousand, so you need to run an appliance, consuming one watt of energy an hour for 1000 hours to consume 1 kWh. Now in Ontario, where I live, consumer pays about 10 cents a kWh. Let’s calculate, amount of energy that would consume energy efficient bulb running 24/7 for a whole month:

9 Watt * 24 (number of hours in the day) * 30 (number of days in the month) / 1000 = 6.48 kWh.

So, giving the price of energy about 10 cents per kWh – you’ll pay about 65 cents at the end of the month.

Rule of thumb – every 10 Watts of energy you consume on ongoing basis cost you 70 cents a month.

If you’ll do the same calculations for microwave oven – replace 9 with 1475 and you’ll get 1062 kWh or $106 hydro bill. For sure you are not running you microwave 24/7, normally it sits idle and consumes only fraction of watt of energy, enough to light up electronic clock on a control panel. Let’s say you run microwave only 10 minutes a day:

1475 Watt/60 (minutes in the hour) * 10 (minutes a day) * 30 (days in the month) / 1000 = 7.375 kWh or 74 cents a month.

With very few exceptions like refrigerator or electric water heater your electronics and appliances do not consume a lot of energy on ongoing basis. But a lot of them are guilty in what is called idle energy consumption.

Idle Energy Consumption

TV, waiting for a wake-up signal from a remote control. Microwave oven, radio clock, wireless telephone base – they all consume a little, but, unlike light bulb or microwave oven warming your milk - they consume this idle energy 24/7. And this 24/7 can add up.
So I’ve tried few of my home electronics and appliances for this idle energy. TV and microwave did great. Energy Meter was just unable to catch any activity unless you let it run for at least half an hour. Wireless telephone 3 Watts. Well probably it have to listen all the time for a phone to wake up.

What really surprised me was my Rogers cable box. It consumes 15 watts than up and running and 12-14 while idle. Do the math we did above for a light bulb, you'll get 86 cents a month just for idling cable box. Sounds not that much, but at the same time it’s almost 1% of my total monthly bill!!!

There is this black thing, doing nothing most of the day and still responsible for 1% of my entire house’s energy needs. Looks really wired! You may try to think of it another way – every 100 Roger’s customers without their knowledge consume electricity enough to keep single household up and running. Just because this Rogers box is there.

Take a look here for details on Energy Meter: In Kingston, ON you can actually borrow Energy Meter for free in a local library! Such a great idea.


Anonymous said...
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