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How to measure the power consumption of electrical devices

How to measure the power consumption of electrical devices

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Following my how much power do each of my household applicances use you may be wondering how to measure the power consumption of your own devices both at home and perhaps at work too.

I used a device very similar to the plug-in main power and energy monitor as advertised at the afore mentioned link - many alternative devices are available of course from a wide range of vendors. I simply plugged a multi-way mains extension strip into the energy monitor and then each of the devices I wanted to test into the power strip - turning each on and off according to the combination I wanted to test. If you do this yourself be careful not to overload the power rating of the power strip.

Note: I didn't test the actual consumption of the heated towel rail as it's consumption was clearly labeled on the applicance itself.

There are some much more sophisticated devices available including those like the Wattson01 which is available from diykyoto. The Wattson01 appears to have a cool design and can be linked to a PC to provide ongoing analytics - it's also much more expensive than the basic energy monitors I mentioned earlier. I haven't tried one of these for myself though according to the website it's pretty straightforward to setup - you can read all about how it works on the website - it's based on a clip that you place around the power cable you want to measure the consumption of.

Here's a picture of the device:

I've even heard of people who find it compulsive to test different combinations and work out the deltas of how many Watts they can save!

BTW thanks to Cristiano Betta for letting me know about this device

Comments
  • The Wattson has been criticised for its own power usage -- something like 7W -- but it is a very nice looking device.

    There are cheaper alternatives that are less attractive, and several of the UK power companies will give you one free if you switch to one of their "greener" tariff schemes.

    See http://www.electricity-monitor.com for a nice summary of the various options.

    I found it most enlightening; in particular my old eMac consumed the same power (9W) on standby as it did when "switched off"!

  • Nik> That's a very good point re. the power consumption of the Wattson.

    I'm using a device that's very similar to the one sold by Maplins - it uses a couple of watch batteries to power it's display and I think that's about it

  • I use one of the plugins, they're very handy for fine tuning low power PCs.

    Re the Wattson it's a tradeoff; if having such a device means you save more than it consumes (which is pretty likely), then you're in "credit" so to speak.

  • Thanks to the Imagine Cup this year, I've spent quite a lot of time talking to government agencies, NGOs

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