We measure the power consumption of household appliances

Hello colleagues, I want to tell you about my little experience in the real measurement of the power of home appliances and your computer.

Preamble
After billing me with large electricity bills, I decided to audit my electrical appliances and check which appliance actually consumes how much and how much it will cost me. As a result, I decided to purchase a local (i.e. plug-in device, rather than an electrical box) a kWh counting device.

Device selection
What is sold in the shops of my city, to put it mildly, did not suit me at all for the price (from 1k rubles) and even by functionality, therefore I bought something from the Chinese for the EU Version Power Balance Energy Meter for just 600r. A little about the device. The device allows you to measure power from 1 W to 3 kW, stores information about the electricity consumption during the session and for all the time, considers the cost of consumed electricity at a given price of kWh, shows the mains voltage, there is a bunch of alarms for exceeding any threshold. Overall very comfortable.


We measure everything and everyone
Lamp
The first thing I decided to measure is how much the instrument actually shows the power of the electrical device. Take an ordinary incandescent lamp and check

Lamp power, W	60	90	100
Instrument readings, W	60.5	89.8	101

Yeah, great, we see that the device shows exactly and there are no double standards in power measurement in the Russian Federation and China.
')
Computer
I immediately want to point out that my home computer is very specific and, I think, most people still have normal computers. So, I have supermicro x6dvl-eg, 2 x Xeon 3GHz, 4GB ECC, 2 HDD, 500W FSP, radeon 5670 512Mb. In short, the old server Nurse remnant of the deceased server, soldered and returned to the system.
Monitor DELL U2212HM

Turn on the computer through the device and see the power consumption.

Mode	Instrument readings W,
Loading computer	350
Torento mode	190
Render video	350
Gamay in Diablo 3	300
Wife + classmates	270

Question: Why do I need a 550 W power supply if, together with Monique, the system does not go well, the edge is 400 W? Cheating on consumers?
In general, the results are sad: the whole system consumes an average of 250 watts. What a bit too much.

I decided to leave the device in the network and see how many it will run over a long period. As a result, we have
12 days uptime, of which the 3rd day torrent mode, the rest 2-4 hours per day, 12-day power consumption was 24kWh, which is equivalent to the cost of 2.22 per kWh (I have) 60p.

Calculate the cost per month. We get 60/12 * 31 = 155r. Here is such an interesting mathematics. that is, connecting the Internet home for 400 rubles / month, we have overhead costs for a computer for another 155 rubles for electricity without weak use.

Other electrical appliances
Pomeryv comp, set out to measure all electrical appliances in the house. The results surprised. ALL devices that I measured, it turns out, have a power less than that declared by the manufacturer by about 20%! Robbery gentlemen! Were measured at full power: iron, washing machine, microwave, vacuum cleaner.
The only electrical appliance that matched the declared capacity was the 1978 samovar of the year of release. Its heating element on the passport 1kW, in fact 950W.
As a joke, I measured the cost of washing 15 pairs of socks (at the same time) in a washing machine. Out 2 rub.

Updated 09/29/2012
At the request of habrovchan lay out the results of measurements

Device	Instrument readings W,
DSL wifi router	five
TV samsung 40`` 2011 onwards LCD standby	0.0 (!)
TV samsung 40`` 2011 onwards LCD in TV mode	70
Sharp TV 14`` CRT 1993 onwards In standby	7
Sharp TV 14`` CRT 1993 onwards in tv mode	47
Phone charging	2.8
Charging netbook Aser aspire one - off	15
Charging netbook Aser aspire one - included	20-30
Microwave samsung 2008 onwards In standby	four

Now, if someone is interested in the measurement of any device, I think, if there is one, I can post information.