appliance electricity cost


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 and are used by permission. I found out my equations for that were incorrect as of 2/2014.

Appliance Cost Calculator Application

Enter either Volts and Amps, VA, or Watts.

, used with PF.

(can be in 00:00:00 or any combination of 0 hours/hrs/hr 0 min/mins/minutes/mn 0 sec/secs 0 ms/milliseconds)

Result: 0.00 cost per month

Result: 0.00 cost per year

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).

VA=rmsVolts×rmsAmps PF = W PF

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

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

V(olts) × A(amps) = 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:

$ month = W × HoursOn × 31days × $0.0816perkWH 1000


$ month = V × A × HoursOn × 31days × $0.0816perkWH 1000


$ month = VA PF × HoursOn × 31days × $0.0816perkWH 1000 = VA 0.68 × HoursOn × 31days × $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.

Appliances/Devices, their cost, and usage
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
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
Color Laser Workgroup Printer 1200W 100W:standby, 600W:avg 8h5d/wk $1.45:standby