Another Always On Question…

I’ve read several posts, explanations of how always on is calculated but as a non-electrical engineer by profession…I’m a bit confused although I’ve worked electrical sub-systems in past jobs. My question I think is simple but concerned there is not a simple answer.

If I have say a fan that runs 24 hours a day on a TP-Link/Kasa plug (I have several…trust me) if I scheduled it to not run say 2 hours a day, would that change my daily Always On even though I see this plug usage separately?

We’ve completed a long of home repair/improvements over the last year and my energy usage has increased significantly but I’ve seen my Always On also go up a lot since installing Sense basically 2 years ago. Several of the items show usage plus “Always On” so I’m trying to confirm or not if there is a “double dip” of usage. Fairly sure that my utility usage has been less than (not a lot) than my Sense usage (not a lot, could be day range difference always moving by utility company) but really want to make sure.

My monthly budget has went up a lot from last year (yes I have added a lot of needed things that drain electricity) but seems excessive for some reason. Just want a sanity check that if I peeled back some of these 24 hr run time systems to say 20-21 hours a day if that would show a change or not. I realize per articles it is average of mains but I’m not 100% following what that really means to all the stuff I have running and all the TP Link/Kasa plugs I have.

Appreciate any guidance or understanding. As I’m a mechanical engineer and not electrical engineer, explaining what is being done for Always On in the simplest terms would be great for my understanding! I do home improvement wiring so I do know enough but how it pertains to Sense and my dashboard is what I really want to understand on a simplistic level.

I’m going to start with the definition, deconstruct what that means using my home data, then try answer your question with a little more of a foundation as well.

Always On Definition
Always On is a calculation of the lowest power of each of your mains, added together, where “lowest” refers to the 1% bin of the observed wattage histogram over the previous 24-48 hour period. It is updated every half second, though most users will not see significant real-time changes given the 48 hour lookback window.

Example
Here’s a visualization of Always On calculation based on data from my house for the past 48 hours. I’m using data sampled from my Sense every 2 minutes (1440 samples), instead of the every 1/2 second analysis Sense uses, so my results will be a little different (higher) than what Sense comes up with.

Here’s the past 48 hours on my Power Meter

And here’s the same sampled power data in an environment where I can do analysis.
The top chart is essentially the same as in my Sense Power Meter for the same period. The bottom is the all those power data samples arranged in a histogram, where each bin is 200W.

The statistical value Sense uses for Always On, the 1% bin, is the value where 1% of all the samples are less than that number. So the Always On is essentially the near minimum over the trailing 48hr period. For this data set, that calculates to 560W. Another way to think about the 1% bin is that means there are roughy 1/2 hour of data points over the past 48 hours that are smaller than Always On and 47 1/2 hour of data points greater than Always On.

Answer
Back to your question about known devices that are on pretty much all of the time, you really have two options.

  • Try to peel back to the minimal Always On by turning off the “sorta Always On” devices for an hour or two as you suggest. You’ll want to turn them all off at the same time window, at the time when you think your house is at it’s quietest. That still might leave you with a number that’s a little higher than the underlying Always On, because that time window might miss some of the lowest data points, but it should collect most of them.

  • There’s also the option of simply leaving those devices on all the time, letting them all contribute to Always on, then measuring each devices’ Always On, and manually adding it as a broken out item in the Always On list. See the send of this for a little more on adding Always On estimates.

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