How Accurate is the "Now" reading?

#1

I know that the “Always on” number is like an average. At least that is what I have been told here previously. Because at one point I flipped every breaker except the one for Sense and the router/modem, and the “always on” figure didn’t change. And so I was told that it is a kind of daily average.

When I add that number to the other devices and “other” I get the total number that it is telling me. So that begs me to ask the question(s):

is the total number accurate, or:
is it a figure based in part on the “always on” estimation, or
is the number of W being issued to other devices and “other” an estimation based on the accurate total minus “always on”

You know what I mean? in order for all the devices to add up perfectly, if “always on” is not perfectly correct, then there must be a mistake with one of the other categories as well.

edit: at the end of the month, my power usage pretty much matches up with the meter. there is always a small difference, but I don’t know what time the guy from Entergy reads my meter. It’s not digital either, so there is a margin of error there. but I wonder if the data is accurate in the present, or if it is corrected by Sense later on after some time has passed, and the current reading is more of an estimate.

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#2

Always On is a little different calculation than an Average. Without smart plugs it is pretty much a rolling MIN function for all readings over the last 48 hour period of time, with some filtering to remove possible data dropouts (where usage drops to zero for a short period). It gets a little more complicated when you add smart plugs, because the Always Ons for each smart plug get subtracted from the overall Always On, because they are now part of the total energy usage of a known device.

As such, Always On is a good approximation of how much power has been consumed at a constant level in your house over the past couple days. “Other” becomes what’s left after subtracting all the device usage plus Always on from the Total Usage.

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#3

I just replaced all my dead light bulbs, then flipped them off at the light switch command center (We wired this house before the advent of smart-bulbs :wink: ) because they weren’t necessary anyway. 4 cans out of 20 is enough light for just me. but during the day, But it can get depressing sometimes with a lack of light so it is nice to be able to turn more on if need be. But it is nice to know that the bulb that is burnt out or even (in the case of burnt out CFLs) prone to smoking… and shut off my desktop. Always On plus everything else is now adding to be more than the total usage. so I guess that makes the immediate total usage a reliable number :slight_smile:

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#4

This is weird… why am I using a baseline of 200W (the Now usage, not the “always on” figure) more than last year. I haven’t changed anything. I’m now walking around the house looking for something that ought not be plugged in. lol.

edit: 3 days ago on the 7th. that’s the last day with a baseline of 110 at 7:49 AM on the 8th. the Furnace turned on. and since then…

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#5

Doh!!! I forgot to turn off the Attic Fan after I was finished checking my furnace the other night… Dagnabbit!
Got to wondering if I forgot the attic lights on. and then a moment later it hit me.

Peace and order are restored in the universe.

@kevin1 that’s good. Because I don’t feel comfortable with that fan running. it makes me nervous. There is no reason for me to think or feel this, but the fact that it is a big metal fan, runs on electricity, and I can’t see or hear it, and it’s a hassle to get to (I have a light switch in the house that controls it). I’m just nervous the thing might catch on fire.

Furnace probably ran a lot more in the last couple days too.

Way to go Sense! :slight_smile: too bad you haven’t detected it. I could have known I forgot it on sooner. lol. but I’m too afraid to run it often enough for Sense to detect it.

Can’t totally blame the attic fan for that 2.5 hours of furnace run time… but is a pretty unusual length of runtime. and if I learned anything in my Physics coursework… it certainly makes sense that it would contribute.

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#6

Glad that peace and order are restored. Not sure I ended up answering your original questions about accuracy, but I think in the context of your question:

Sense “Now” is typically quite accurate. The accuracy of “Now” doesn’t depends on Always On estimation - It’s entirely based on the data flowing from voltages on your mains and the CTs on your mains (plus solar CTs if you have them). “Other” is the bubble category that is impacted by any estimation inaccuracies in Always On.

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#7

A bit OT, but you need not worry that your attic fan is going to burst into flames or anything - electric motors are very reliable in modern day - anything that would cause a fire is typically going to result in a popped breaker to begin with…and usually a LOT of noise beforehand that would tell you something is failing likely for days or weeks before anything serious happens.

Back in the 70’s and 80’s (before the days of central AC being commonplace) we lived in a very large ranch style house with no AC - there were 3 attic fans that ran 24/7 for months at a time to evacuate the hot air and help keep the house cooler. Never had an issue.

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#8

it was probably installed in 90s. it’s just in a hard to reach location, and after the issues with my blower motor where the capacitor exploded and the motor failed (not necessarily in that order), and the circuit board died. Had to replace all of it myself. it just makes me nervous. Except with the blower motor I knew immediately because of the smell.

I don’t know about keeping the house cool though. I’ve read both arguments, and my training in Physics tells me both sides make good points. On the one hand, a cooler attic does slow down heat transfer. on the other hand, the fan keeping the air moving through the attic across my ceiling, the air ducts, and ac unit, can also increase heat transfer.

in my case, I would rather the hot air in the attic at this point in time. 2 years ago i had my ac recharged and immediately afterwards it filled up with water and ruined the insulation. I realized that this occurred because the condensation that collected on the outside dripped down into the ceiling and did some water damage. minor enough that I haven’t bothered to fix it (sheetrocking was never my strongsuit. I was better at insulating lol, my older brother and dad handled the sheetrock). anyways, I had to rip out the old insulation and dry out the inside, and then discovered that a regular joe like myself can’t buy the insulation that goes inside the unit. and I couldn’t afford to pay a guy.

so the part of the air supply that comes after the evaporator coil (where the air ducts attach) is missing some of its insulation on the inside. this helped with the condensation forming on the outside, since the heat capacity of aluminum (or whatever the air handler is made of) is much much less than the heat capacity of water that was being held in the box and soaked in the insulation. But I still have aluminum pans under it to collect the drippings. and while circulating the air in the attic might keep it cool, it will also keep the relative humidity of air passing over the air handler high. so, I barely run my ac as it is anyway.
I graduated from school in December, if I ever find a job… I need to buy a new unit. my hvac guy says only the air handler (and its components) actually need replacing. he can save me some money and just retrofit the outside unit for the newer, more environmentally friendly, refrigerant.

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