This looks very similar (although less expensive) to my Kill A Watt, only with the outlet you'll need: Plug-In Energy Consumption Monitor
From the page:
Ideal to find the electricity consumption and running costs of:
- Fridges and Freezers
- Computers and all associated peripherals
- Standby Costs of TV, DVD, computer, stereo, video, chargers etc
- Washing Machines - Find the cost of your 30, 40, 60 degree wash
- Dehumidifiers & Air Con units
- Pond pumps, Swimming pool pumps (if they have a plug)
- Televisions - CRT, LCD or Plasma
- Anything that plugs into a wall socket !
Simply plug this monitor into the wall then plug the item into the monitor and you'll see exactly how much electricity it consumes. Once you have this figure it's easy to work out the running cost.