Do the Flex Sensor net usage from Other or Always On category? Or is it double counting the energy?

After installing my Sense a few months ago I’ve noticed a large Always On category. Most of my big items have been detected, and I’ve put a few smart plugs to monitor the rest (TV’s, monitors, desktops, etc.) I added the Flex Sensors on a breaker that goes to a sub panel when it was installed. I am curious if Sense net’s that usage out of the Always On/Other categories, or is it double counting the energy? Since I installed the Flex Sensors in the beginning, there weren’t any devices discovered yet.

To start with, most devices have both a dynamic / switched and Always On components to them - so it takes a little more digging to understand how to sort out Always On when dealing with devices on Flex Sensors or smartplugs vs. native detections.

As an example, my upstairs furnace on a smartplug uses a constant 8W (Always On) to power the internal control board and the associated thermostat - that device level Always On is even calculated by Sense. When the AC kicks in, the furnace blower turns on, causing the usage to go to 350W. That additional 342W is what I would call a dynamic power component. Sense native detection would only be capable of finding dynamic components part, but not the Always On part, but smartplugs/Flex Sensors see everything.

So when you add a smartplug or Flex Sensor, here’s what happens:

  • Sense uses the measurements from the smartplugs for the device
  • Sense subtracts off the entire usage of the device(s) on the smartplug(s)/Flex Sensor(s) as well as all the other devices it has detected as on at that point in time (including the house level Always On) to calculate the Other bubble.
  • Sense does NOT currently subtract off the calculated Always On for the smartplug from the total house Always On.
  • So just to restate you have to think about the device on the smartplug/Flex Sensor as having two different components, an Always On part and a dynamic part. Each gets treated a little differently for purposes of accounting. When you add a device on a smartplug, Sense will subtract off the full usage of that device (Always On and dynamic) to get Other. But the Always On component from the smartplug is NOT subtracted from the house level Always On. So the Other gets reduced a bit due to double subtraction of the Always On part.

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I think I’m following. As I read this breakdown on my Always On, many of the devices that are on Smart plugs are broken down as their share of the Always On. So that Always On share, may double count when those devices are on in the Other category. In this current example, the estimated unknown of 932w is where I’m still having trouble. It’s not showing tied to any device.

I don’t have any major appliances that use that kind of energy that are truly Always on. Let alone ones that haven’t been recognized when they turn on an off (Most major ones have been found)


You are correct about the double counting of the Always On component for those smartplugs and via the whole house Always On, which actually artificially shrinks Other a little. But let’s put that aside and answer your other question.

From what I see in your Always On list, you have a total of 283W + 932W or 1215W of house level Always On right now - that should roughly be the number reflected in the Always On bubble. Of the 1215W, Sense is aware of the sources of 283W, either via the smartplugs or thank to you adding in known devices that have known Always On (like the Google Nest Wifi Points or Sonos Play:3).

There are a number of ways to search for that remaining 932W of house level Always On.

  • Subtractive - you can watch your Sense Power Meter when your house is at its quietest (probably early AM), when your total usage is probably close to 1300W, while you flip off breakers or unplug devices. The flips / unplug that give the biggest drops in usage are the biggest potential Always On “offenders”
  • Sleuthing - you can also use a traveller smartplug to try every device in the house that is plugged in and easy to access. After 24 plus hours, the smartplug will give you the Always On for that device. But that won’t work for wired devices (lights, some furnaces) and 240V equipment.

Adding to @kevin1 comments:

I didn’t see in your posted list all of the very small devices that can add up quickly.

Do you have:

  • smoke detectors
  • garage door openers
  • doorbell transformers
  • wired thermostats
  • Smart devices - that send Z-Wave, Zigbee, Wifi communications
  • clocks
  • TV’s that are actually ON when they are turned OFF
  • Satellite receivers
  • Anything with a small LED light
  • Night lights
  • Outdoor lighting - nighttime
  • battery chargers in the garage

You can probably think of more. Start an EXCEL spreadsheet and make a note of every item plugged in. You will be amazed at how many devices are using power continuously. I have 113 ‘Always On’ devices in my home. Measure, check the Mfg wattage or guess a wattage (like 1 watt) - I think your numbers will add up more quickly than you realize.

Good Luck!


I’ll have to try that subtractive method. At least that will give me the circuits that the major loads are coming from.

I definitely have a lot in that 1W range that falls below the screenshot, but nowhere near the amount that would make up 900+ watts. Almost everything I have has been detected, or on a smart switch, or has minimal load.

Just make sure you do it watching the Sense Power Meter, not the Always On bubble. The Always On bubble number uses a statistical calculation on all the data for the past 48 hours, so it changes relatively slowly, and won’t reflect the full affect of flipping the breaker off for 48 hours or so.

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