the information you enter here runs only on your browser on your machine, no data is transmitted to a server unless you use bookmark URL button, then it submits to same page (nothing active on server side) and builds a URL. the equations for PF,W,VA are on rapidtables.com and are used by permission. I found out my equations for that were incorrect as of 2/2014.

## Appliance Cost Calculator Application

Note: appliances with cooling or heating will only be on a percentage of the time, probably 20%-50%. so you can halve the cost or the time.

VA is not Watts(W).

$\mathrm{VA}=\mathrm{rmsVolts}\times \frac{\mathrm{rmsAmps}}{\mathrm{PF}}=\frac{W}{\mathrm{PF}}$

$\mathrm{PF}=\frac{\mathrm{VA}}{W}$

Where PF is power factor. (rms is Root Mean Squared).

When measuring my computer, PF was 0.68. see article on VA vs. Watts.

$\mathrm{V(olts)}\times \mathrm{A(amps)}=\mathrm{W(atts)}$

Using the Kill-A-Watt EZ or PS 10 power WattMeter is a good way to get the real wattage used.

feed it into your calculator one of 2 ways:

$\frac{\$}{\mathrm{month}}=\frac{W\times \mathrm{HoursOn}\times \mathrm{31days}\times \mathrm{\$0.0816perkWH}}{1000}$ $$

or

$\frac{\$}{\mathrm{month}}=\frac{V\times A\times \mathrm{HoursOn}\times \mathrm{31days}\times \mathrm{\$0.0816perkWH}}{1000}$ $$

or

$\frac{\$}{\mathrm{month}}=\frac{\frac{\mathrm{VA}}{\mathrm{PF}}\times \mathrm{HoursOn}\times \mathrm{31days}\times \mathrm{\$0.0816perkWH}}{1000}=\frac{\frac{\mathrm{VA}}{0.68}\times \mathrm{HoursOn}\times \mathrm{31days}\times \mathrm{\$0.0816perkWH}}{1000}$

See Clark PUD article on the equation. It's actually 120V not 115V, because I measured it. that was probably a typo or some accidental misinfo (or maybe it didn't get updated in years).

most plug-in appliances run on 120V (120VAC). clothes dryers & stoves: check your circuit breaker & multiply by 220V. your clothes washer 15A, dishwasher 20A, microwave 15A-20A, fridge probably run on 15A (check your breaker or back of fridge).

remember, this is worst-case cost.

found the equation on the PUD web site (cool!). hard to find.

There is also the P3 International Kill-A-Watt Power Usage Meter for $21-60. Also at Home Depot and Lowe's.

device/appliance | power rating | power actually used | time on | $/mo | $/yr |
---|---|---|---|---|---|

An HP OfficeJet Pro 8500 Wireless a909g | 120V@1800mA=1.8A=216W | 120VAC@0.14A=16.8W:sleep 120V@0.58A=69.6W:print | 23hrs55min7d/wk:sleep print:5min3d/wk | $0.73:sleep $0.44:print |
$8.71:sleep $5.23:print |

250W old 2004 xp desktop computer | 250W | 172W | 12h7d/wk | $5.22 | $62.65 |

160W old win98 computer | 160W | 47W | 8h6d/wk | $0.82 | $9.78 |

regular desktop | 430W | 185W | 12h7d/wk | $5.62 | $67.39 |

23" LED monitor | 120VAC@2.1A=252W | 50.4W | 12h7d/wk | $2.04 | $24.48 |

Logitech high-end speakers | 200W | 26W | 24/7 | $1.58 | $18.94 |

top-end desktop PC with 3 video cards | 960W | W | 4h7d/wk | $ | $ |

top-end desktop PC with 4 video cards | 1200W | W | 4h7d/wk | $ | $ |

top-end desktop PC with 4 video cards | 1500W | W | 4h7d/wk | $ | $ |

top-end desktop PC with 1 medium-high-end video card, multithreaded work | 850W | 135W | 12h7d/wk | $4.10 | $49.18 |

Cuisinart coffee pot | 900W | 120V@7A=840W | 1-2h7d/wk | $4.25 | $51/yr |

1200W hair dryer | 1200W | 1200W:HI, 340W:LO, 62W:COOL | 10min7d/wk | $0.51:HI, $0.14:LO, $0.03:COOL | $6.07/yr:HI, $1.72/yr:LO, $0.31/yr:COOL |

1875W hair dryer | 1875W | 1405W:HI, 390W:LO | 10min7d/wk | $0.59:HI, $0.16:LO | $7.11/yr:HI, $1.97/yr:LO |

toaster | 1600W | 1600W | 10min7d/wk | $0.67 | $8.09/yr |

Toaster | 900W (120VAC@7.5A) | 900W | 10min7d/wk | $0.38 | $4.55/yr |

Mono Laser Workgroup Printer | 800W | 24W:standby, 600W:print, 300W:avg | 8h5d/wk | $0.35:standby $8.67:print $4.34:avg |
$4.16/yr:standby $104.07/yr:print $52.04:avg |

Color Laser Workgroup Printer | 1200W | 100W:standby, 600W:avg | 8h5d/wk | $1.45:standby $8.67:avg |
$17.35/yr:standby $104.07/yr:avg |