Quote from: BombaUcigasa on June 08, 2013, 02:06:19 PM

Quote from: phillipsjk on June 06, 2013, 02:36:56 AM

They have devices that read the glass bubble for you and calculate power usage as well.

http://www.mymeterstore.com/p3982/power_cost_monitor.php

According to that page, the Blueline Innovations 28000 is now discontinued though.

The listed price is 20 USD or so, so it would be on par with a watt-meter. Since it's discontinued, you can only safely measure your consumption by using a dedicated watt-meter or looking at your electric meter.

Other unsafe methods involve using an amp-meter on your power cable (unsafe and costly) or an induction amp-meter (possibly unsafe and costlier). Personally I have this:

http://i.imgur.com/RU6Zb8K.jpg

Things like that and the Kill-A-Watt are the best solution.
You can't get an accurate measurement just by measuring the current, because you aren't measuring voltage and calculating power factor.
Also, with inductive ammeters, you still have to separate the wires in the cable and clamp around only one of them. If you clamp around the all of them, it will read zero.