Agree.
As mentioned, the only “good” way to measure power is to use high speed ADCs and perform simultaneous measurements of instantaneous current and instantaneous voltage. Multiply each pair, take an average over a time interval (preferably an integer number of cycles) and then display it on the LCD. It will be real, average power, which is what you want. And with this technique you don’t have to worry about true RMS, phase angles, etc.
This obviously varies depending on your electricity provider, but mine has a web page that allows you to view your hourly whole-house electric usage. That’s not going to tell you which device is using power, but it’s an easy way to compare total usage across various times, days and seasons.
Most power draws -
AC (summer); dryer; electric stove; dishwasher (heat element dry cycle); hot water heater; furnace fan (assuming you don’t use electrical heaters);
I would wonder if you had a hot water drip somewhere too…or did a lot more laundry or dishes compared to last year, or took longer showers.
Surely, the “good” way to measure power is to use the same technique that your electric meter is using, whatever that is.
It’s the same as I described:
The metering engine is given the voltage and current inputs and has a voltage reference, samplers and quantisers followed by an analog to digital conversion section to yield the digitised equivalents of all the inputs. These inputs are then processed using a digital signal processor to calculate the various metering parameters. (Cite)
Today electronic metering technology uses Digital Signal Sampling of the analogue values of voltage and current and transforms them into a series of digital values, or a series of samples. The more samples in a specific period of time the more accurate the reading. (Cite)
If it is relevant, I assume you have to know exactly what they charge you for a low “power factor” or for a really crazy load.
There usually isn’t any surcharge for a low power factor, harmonic distortion, etc. in residential metering.
Yea, so far they haven’t hassled homeowners about poor power factor. Could change in the future, though.