electrodacus wrote:
But I will calculate for you as an example what a 10W difference will save you on electric bill. I will assume you use the computer 12h a day 7 day a week for one year. So you have 10W x 12h x 365days = 43800wh this is 43.8kWh at 10 cent /kWh is 4.38$ so less than 5$ :)
I do not think you can make any upgrade for 5 or 10 $ I live in Canada and the price here is about 10 cent/kWh but is not completely true because if you use as I do about 300kWh/month the I pay about 60$ for this since there is a fix monthly surcharge + some municipal surcharge and some taxes and in the end I pay 20 cent /kWh
1. Let's assume 10 cents per kWh. You were going to have to pay those fixed costs no matter what (until you go to wind and sun - and even then you have to pay another form of fixed costs).
2. Saving 10 watts will produce a savings of 87600 watt hours if you calculate it at 10W x 24 hrs x 365 days
(electrodacus why did you use 12 hours in your calculation?)
3. So Saving 10 Watts = Saving 87.6 kWh per year
At 10 cent /kWh this produces a savings of:
8.76 over one year
$26 over three years
$44 over five years
$88 over 10 years (not calculating in the time value of money which reduces the savings)
Other Factors:
(a)
Manufacturing Costs. As Ksanderash points out, if the purchase of a new system or new components results in non-use of the old system or the manufacture of a new system that otherwise would not be manufactured, you actually are increasing total energy usage in the world by the amount of energy it costs to manufacture the new system.
(b)
Capital Cost of Producing the Extra Watts. If you plan to go off grid, generating your own energy by wind or solar, the reduction of the need for 10 watts, might save you a lot more money in reducing the capital cost of generating that 10 watts (and I guess your time and/or labor costs). I don't know what that costs. My guess would be maybe $50 or $100 for an additional 10 watts of peak air or sun generated energy - what with batteries and all.
One major correction to the above
So the one thing I am missing is that 1kw of energy generates 4kw of air conditioning load, if you are in a climate where you are running air conditioning you need to multiply the above numbers. Let's say you are running air conditioning for 6 months of the year you need to multiply the above numbers by 2. And you get:
Saving 10 Watts = Saving 87.6 kWh per year x 2
At 10 cent /kWh this produces a savings of:
$18 over one year
$52 over three years
$88 over five years
$176 over 10 years (not calculating in the time value of money which reduces the savings)