Help understand device detection with smart plugs

Can someone help me understand the the device detection when using a smart plug.

Currently, I have a space heater in a closed off room. My Sense system is newer, so I don’t have a lot of data. However, sense recently discovered another “heat 1” that I am trying to figure out what it is finding.

Heater on smart plug:

Heat 1:

I only have one space here in the house, so I am a little confused on what would be pulling ~1,400w on average. The heater on the smart plug starts around that, then drops to ~800w.

As I was typing this, heat 1 was detected on:

After heater wattage dropped:

Could this be a conflicting detection?

The “detected” Heater could pretty much be any device that uses resistive heating (a stove burner, oven, dryer, hot water dispenser, coffee maker). It seems to be coming on far less frequently than your actual heater, though I always take the usage summary statistics with a grain of salt. Three thoughts on tracking the actual device down:

  • Set an Alert for when Heat 1 turns on and off - try to correlate the Alerts with sounds or actions in your space.
  • Use the Power Meter and the Heat 1 Power Meter (only available in iOS/Android app) rather than the usage summary / Trends to gain insight into what the waveform looks like.
  • if you do suspect something of being Heat 1 try watching the Power Meter as you turn that device or breaker off. You might not see the Bubble disappear, but you will see the Power Meter drop.

Hi Kevin1,

Thanks for the input. I think I think i managed to track it down to the hot water heater. With it being gas, I guess I just didn’t expect it to be pulling so much wattage.


That’s an awful large amount of on time and wattage for the starter on a Gas water heater.

I thought it seemed high, but it does have a power vent on it on it–based on the information panel, it claims < 12 amps, which would net another 1400w. I have been considering going the route of tankless, as this specific one doesn’t really fit the needs of my house–mainly the 130 gallon Jacuzzi tub.

One thing did confuse me, though. I setup notifications in Sense, and it seemed to correspond with it kicking on, however standing next to it, Sense was reading it was off while it was still running. I am assuming it has some sort of cycle that drops some power usage. I am considering putting another energy monitoring plug to watch it more closely.


I’ve never seen a gas HW heater with a “power vent”, so I have no opinion on what you should do next.

I’d mention that the “energy monitoring plugs” available in the US are all 110v. For those of us with electric HW it would be great if someone offered a 220v energy monitoring module we could wire into the 220v line, particularly for those all devices that Sense can’t accurately track.

When I bought a GE Geospring for my old house, i actually bought an inline kwh meter for it. It worked great for paper monitoring, but definitely wasn’t smart monitoring by any means. I know there probably isn’t much of a smart for 220v smart plugs, but I agree it would be nice.

If you don’t have solar, which it sounds like you don’t if you’re talking about a tankless gas water heater, I would steer you toward a heat pump water heater with as big a tank as you can get. Even use your existing gas tank inline as a backup and added buffer. Use a Sense DCM (Flex sensor) on the electric tank. A heat pump tank will likely save you a lot over time as gas prices increase (dramatically I’m guessing) and electricity prices fall or at least plateau.

I would tough it out for a year or so and wait for CO2-based heat pumps to become more common.

BTW: You could probably even work with a 120V system (no resistive element activation) and save on potentially having expensive wiring installed.

If its really pulling that much power and cycling that frequently, I’d be surprised. My 60 gallon unit (also power vent) draws 60 watts while running and 150 while the ignitor is on. It usually runs during times we’re using water (laundry, bathing, etc.) And it will cycle once every 10 hours or so when idle.

Sense has not been able to detect my water heater. Just last night I decided to put it on a smart plug for a couple weeks just to see if the data will show anything useful.

In my experience, detected devices are generally pretty darned accurate, especially “heat” devices. If Sense does “detect” a device that is connected to a smart plug, the statistics (avg. power, runtimes, etc.) between the two should be very similar. If v this does happen, you just “tell” Sense that the new device is plugged into the cooresponding plug so that the data for the two devices can be “merged.” I would guess that these two are different devices, and suggest you follow @kevin1 's advice if you want to track it down. A smart plug can also be very helpful for investigating mystery devices.

So, I’m scratching my head. Earlier in the thread I saw mention of it being gas, but now see GE Geospring, which is a hybrid electric (e.g heat pump…and an excellent unit) water heater. That certainly explains the relatively high wattage. It also explains Sens’s difficulty detecting it reliably, because Sense doesn’t seem to like many types of heat pumps.

Many gas water heaters use zero electricity, because they still have pilot lights that run on gas all the time. More modern units use an electronic ignition, that uses a tiny amount of electricity to generate a spark and a small amount of electricity to monitor temperature. Both of those would be unlikely to be detectable by Sense and so small that they would hardly be worth tracking for power consumption.

I think the Geospring was the “old house” and the new house has gas? That’s how I read it at least.

Side note: We actually have a Geospring as well and it pulls less than 500 watts when running in heat pump mode. Sense helped me realize how efficient that thing is.

What’s strange (to me) is that looking at the top usage graphs, it appears that “Heat 1” is pulling less than “heater on smart plug” which would make sense because the portable heater itself probably has a blower or whatever, so the Heat 1 that Sense detected is going to be a portion of the total use detected by the smart pug. However, lower in that original post where we see the currently active devices, it’s showing a higher use for Heat 1 vs the smart plug (“Snake Room heater”, eek!). So, it’s confusing…

What brand/model is the heater? Should be easy enough to look up the specs.


The GeoSpring I mentioned was for my old house .

I have another smart plug on order. I am going to throw it on once it arrives. Currently, Sense is showing it as 25% of my usage, if that is the case it seems to be a really expensive 50 gallon water heater.

Is there a way in Sense to layer two power meter graphs on top of each other to compare?

The GeoSpring was amazing–I kind of miss it. The heater I have is oil filled and proportional. The initial start up is around 1400w, then it tapers to the 800s


Anomaly heat:

Looking at them more closely, they seem to be similar on the peak, so maybe they are related and sense is just confusion the drop off of wattage.

The water heater is a Bradford White - RG1PV50S6X.

Spec states that the power vent has a 120V, 3.1A motor so you could assume an average of around 370w so your mystery Heat 1 is very likely something else

It would also be (very) rare for Sense to mistake a motor device (the power vent) for a “heat x” device. The signatures (which are a lot more complicated looking than what you see in the displayed waveforms) are very different for those types of devices.

Sense really doesn’t like things that ramp…it was architected to detect sharp edges. Unfortunately, LOTS of modern systems, particularly the high power draw ones, both ramp and use power proportionately to the need…everything from refrigerators/freezers to dryers, to water heaters, to heat pumps, to pool heaters, etc….even some “smart” space heaters.

My experience is that Sense doesn’t confuse heaters and motors very often, but of course with modern electronic motor and heater controls that may have made it more difficult to differentate.

I wish there were… it would make device identification much easier.

Based on power graphs, it looks like Sense’s mystery heat device IS related to the heater on the smart plug. The three heater cycles at approx. 12:46, 1:17, and 2:01 line up almost exactly with the mystery heat. The problem is the “on” cycles that Sense thinks are part of the heater, but are obviously not (between 12:30 and 12:45).

I think you’ve got two options. Delete the mystery device and hope the next detection is more accurate OR merge the mystery heat with your smart plug and hope Sense learns that the “noise” is actually something different and stops adding it to your heater statistics. I’ve seen that Sense will continue to “refine” a device’s detection signature as it collects more data.

I think i might choose to delete it, if it were up to me.

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I think that is the route I will end up going–but I think I will try to export the graphs to see if I can make any real correlation between the two first.

After pulling the graphs together, I believe they are related.

What kind of heater is it? Just curious more than anything.