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How much will a really good power supply reduce my electrisity bill?

By gamingguy27 ยท 13 replies
Oct 8, 2005
  1. At the moment i have a dodgy Generic 500W psu, could someone tell me the dangers of dodgy psus and how much differnce a good one will make to my electisity bill.

    P.S = I was thinking of getting the Hiper 580W Modular PSU.

  2. chaz d.

    chaz d. TS Rookie Posts: 35

    This is everything you will ever need to know about buying a power supply....

    P.S. Your power supply is not going to have ANY effect on your electric bill....that is also in that link....

    Hope that helps...
    Chaz D.
  3. Merc14

    Merc14 TS Rookie Posts: 171

    As Chaz said, not much of a difference. Few bucks a year maybe if it is on 24/7/365.
  4. blue_dragon

    blue_dragon TS Rookie Posts: 190

    might be yuor cpu eating most of the juice
  5. howard_hopkinso

    howard_hopkinso TS Rookie Posts: 24,177   +19

    The dangers of using a "dodgy" psu are, it could blow up, and take some major parts of your pc with it.

    A good psu is one of the most overlooked parts in a pc.

    You wouldn`t put a crap graphics card in your pc, and expect good performance. The same applies to psu`s.

    The thread that chaz d pointed out really is excellent, and should give you some insight as to the problems with cheap no name psu`s.

    You might also want to take a look at this handy psu wattage calculator HERE. Remember to add another 30% to whatever figure it comes up with.

    This is because even a good quality psu will only achieve around 70% efficiency. A cheap psu won`t get anywhere near that figure.

    Regards Howard :) :)
  6. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

    the more inefficient your PS, the more it will act like a space heater. Good PSUs convert more electricity into usuble power, cheaper ones will simply make more heat.

    The electric bill is negligable. You'll still suck the same amount of juice in either case, but only the more efficient PSU will power more stuff.
  7. gamingguy27

    gamingguy27 TS Enthusiast Topic Starter Posts: 168

    I took your advice and bought a Hiper Type-R 480W PSU, it seems to acctually make the pc more reliable. Was this a good choice?


  8. howard_hopkinso

    howard_hopkinso TS Rookie Posts: 24,177   +19

    I`d say that was a very good choice.

    Hopefully, you can now look forward to many hours of stable computing.

    Regards Howard [​IMG]
  9. VcBoy87

    VcBoy87 TS Rookie Posts: 20

    Wow I'm posting long after everyone is done on this thread talking but...

    I looked at the link chaz d. put out, and I couldn't find any information on power supplies not affecting your electricity bill. But from just piecing things together and context clues, I'm assuming that a 500 watt power supply would not continually suck up 500 watts every hour? And that the power supply only takes in however many watts your computer components need/use?

    I just need some clarification, thanks.
  10. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

    it will suck 500watts.-- most of which is wasted as heat.

    No power supply delivers its rating. a 500 w powr supply delivers anywhere from 400 to 470 watts... this is due to heat loss.

    better PSUs are more efficient.
  11. Merc14

    Merc14 TS Rookie Posts: 171

    This should answer your questions (from PC P&C website):

    This is the biggest myth of all. First, it's important to understand that a power supply only delivers the power that's needed by the system, nothing more. If your PC currently has a 400W supply and the system needs 350W, it will still need and use only 350W - if the only change is upgrading to a 500W power supply (the upgrade makes sense since there are many advantages to running a power supply at a lower percentage of its rated capacity). Whether the electric bill goes up or down is solely determined by the efficiency of the new power supply. Greater efficiency means a lower electric bill because more of the AC power is converted into DC for the computer, rather than wasted as heat. The savings can really add up over time. For example, when the money saved in electricity over the course of its 5-year warranty is taken into account, the efficient, next-gen Turbo-Cool 850 SSI is no more expensive than a standard unit such as the Antec True Power 550. Here's the math:

    Efficiency @ 550W

    Input Power @ 550W
    Turbo-Cool 850 SSI

    Antec True Power 550


    For the same output power, the Turbo-Cool 850 uses 73W less input power.

    5-year savings = .073KW x $0.10/KWH x 24 x 365 x 5 = $319.74
  12. VcBoy87

    VcBoy87 TS Rookie Posts: 20

    What I don't understand now is the numbers for the input power (672 and 745), how did you get them and what do they mean or stand for?

    Thanks in advance.
  13. Merc14

    Merc14 TS Rookie Posts: 171

    Sorry, that didn't cut and paste well. The original is here:

    and a more in-depth discussion is here:

    No PSU is 100% efficient. The work of turning AC into DC creates waste heat and the more efficient a PSU is, the less heat it produces. If the PSU was perfectly efficient it would pull only 550w of AC from the wall to deliver 550w of DC to the system with 0w of waste heat.

    This table compares two PSU's, the PC P&C 850SSI and the Antec True Power 550. The figurative system is asking for 550w of power:

    The 850SSI numbers are 672w AC (pulled from the wall) to produce 550w DC (needed by system) with 122w of waste heat produced
    The Antec True Power 550 numbers are 745w AC (pulled from the wall) to produce 550w DC (needed by the system) with 195w of waste heat produced.

    What that means is the 850SSI pulls 672 watts from the wall to make 550 watts giving you a 81.9% efficiency while the less efficient Antec True Power 550 has to pull 745 watts from the wall to make 550 watts giving you an efficiency of 73.8%. This is meant to illustrate two things. One, efficiency matters and two a larger PSU does not necessarily use more energy to produce DC for your PC and in fact, if it is more efficient, will use less energy.

    Does that help?
  14. VcBoy87

    VcBoy87 TS Rookie Posts: 20

    Yes, thank you so much, your comments have helped me a ton especially your last explanation, that was going an extra mile and perfectly illustrated everything clearly to me.

    In other words, you have enlightened me o-wise one hahaha, thanks again I really appreciated your help!
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