So I wanted to get myself a Kill-a-watt. Being who I am, I wanted information regarding its accuracy, especially at low power draws. I found a comparison with a industry grade equipment (Fluke is about the best out there in handheld electrical meters). It’s not encouraging, so I thought about a more proper meter, but it’s not easy to find an actual power meter that is accurate at low loads, isn’t a hassle to install and doesn’t cost an arm and a leg.
What do you use? Am I overthinking it?
Edit: thanks everyone for chiming in! To clarify a few things:
- I wasn’t (at least initially) looking for a permanent installation on my home server, but rather a good instrument to measure things around the house once I’m done fiddling with the server.
- the comparison with Fluke was just to illustrate what kind of error we can expect from a Kill-a-watt. It would be nice to have a Fluke power meter, but there’s nothing I do at home would even come close to justify it. The kill-a-watt is such an old design and the company behind it seems to focus on cheap trinkets. I was just hoping to find something a bit better than what P3 offers. Wouldn’t mind paying up to $75 for the same features and better accuracy.
- I looked for a multimeter that measured power somehow as I need a better one that can measure capacitance too anyway. Didn’t find it.
In terms of raw data, any properly calibrated equipment should be identical.
You could build one yourself or have a look at how to get readings from your actual electricity meter. Both can be found on the open energy monitor project page. If you self build i guess you could use a lower value CT that amplifies lower currents and just not use it at higher loads?
Mains power fluctuates a LOT though so youll definitely need averaging to some extent
Many residential tools can’t even be calibrated. Even if they are, calibration stability is a concern. The difference between a cheap instrument and a good one is short and long term repeatability.
Thanks for pointing open energy monitor, that seems overkill for what I need.