How Wireless are you at home..

[Siddhartha]

I have finally flash in the tomato firmware into my wireless router and everything works very nicely. Not only can I toggle wireless on/off, I can also reduce the transmission power from the defect 42 mW to 5 mW. Thus saving more on electric bill.

While that sounds like a spectacular reduction in wireless transmission of about 88%, I am sorry to inform you that the savings in your power-bill will be peanuts, if at all any.

The power consumption of your router is usually (pre-) determined by the adaptor. Check it: it probably consumes at least 10W.

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However, for theory's sake, let's assume that reduction in wireless transmission power is going to reduce electricity consumption by an equivalent amount. In that case, you have reduced your power consumption from 42 mW to 5 mW i.e. you have saved 37 mW.

This is a saving 0.037 Watt-Hour.

Assuming you keep your wireless router switched ON 24 x 7, you have achieved an annual power saving of: 0.037 x 24 (hours / day) x 365 (days / year) i.e. 325 Watt-Hours.

Electric Power is measured (and purchased) in Kilowatt-Hour.
So, your annual saving of power is 0.325 Kilowatt-Hours.

Out here, electricity costs 20 Euro-Cents per Kilowatt-Hour i.e. 0.42 Singapore Dollars per Kilowatt Hour.

So, your annual saving in power is = 0.325 * 0.42 = 0.137 Singapore Dollars.

LOL!! That's your saving, in a year.

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Now, let's assume that you switch your adapter OFF for 8 hours a day when you are sleeping.

Let's assume that the wireless router's adapter consumes 10 Watts.
(Many / most consume more... )

Your annual saving in power consumption then stands at = (10 * 24 * 365) = 87600 Watt-Hours = 87.6 KWH.
So, your annual saving in electricity bill by simply switching off that router when you are asleep is = 87.6 * 0.42 = 37 Singapore Dollars.

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That's the math. If you want to save power, switch the router off when you don't need it!

PS: If people unplug their TVs, Stereos, DVD-players, cell-phone and other battery chargers, laptops and PCs when they stop using them, they would save well over 100 Euros / year (over 150 USD / year) - thus doing themselves a big favor and helping the environment too.