Is there a difference between kill-a-watt devices?

[Limmin]

@Machine_Elf

This PDF file compares the features of the three available models of the Kill-A-Watt branded power meter.

A device’s power consumption can vary over time, so if you’re trying to understand power consumption over time for a device, you need a meter that can tell you total kW-h for the time it was plugged in. For your purposes, any other data (volts, amps, phase, etc.) is extra. You can also do the cost math yourself based on the price per kW-h listed on your electricity bill.

Basically, the cheapest meter that reports kW-h is the best value for you.

Agreed! I bought a kill-a-watt over a decade ago. It is really useful. While it can report instantaneous (i.e., right now) levels for current, voltage and power consumption, what is best is the long term energy use, that is, kW-hours.

So, get one, and plug it into various electrical devices for, say, a full day each, and write down the reported kW-hr for each device. Even devices with small power draws will have tallies if they’re recorded for a full day.

I used one to find out that my 1970’s refrigerator used, on average, 360 W of power. It was running almost all the time, super inefficient. The power savings I gained by switching to a newer fridge that only used 60 W on average was enough to pay for the refrigerator, with a break-even term of about 1.5 years.

I then loaned my kill-a-watt to my company’s IT department. They were VERY reluctant to part with it when I had them return it. (Their boss was a micromanager who liked to know how much it cost to run the company’s servers, etc.)