"Oven" Driving Me Crazy

My Sense is telling me we have an Oven that is running almost every hour. It used almost 14Kwh last week. The pattern seems pretty consistent. The device starts at 450w, then goes to 400w for the duration. And, then it drops to 1w or 0w until the cycle starts again.

This device used to run sporadically, but something changed in the afternoon on February 1. Now it runs almost every hour.

I am not at home and am curious what people think this might be. Since the frequency of this device running has increased, I should be able to turn off circuits until I find the one that’s controlling this device.

Do you have a screenshot showing a single day??

Here you go. Here’s a 24-hour view and a partial day view as well.

The spikes at the beginning of each cycle look like a motor starting. Usually my motors or compressors have a mich higher spike. At 400 watts it would have to be a 3-3.5 amp device at 120 volts. Do you ha e a Hot Tub?
Hot tubs usually run hours long cycles or all the time with a tiny motor.
I’m just trying to give you ideas. Somebody with a lot of experience will probably recognize it immediately.

I agree that this looks more like a motor than an oven. We don’t have a hot tub. Our pool has a much larger draw (it hasn’t been identified by Sense yet). The pool pump pulls around 1,800w.

My wife’s current theory (pun?!)… this is the fridge. We purchased a new fridge and had it delivered on Feb 1. Once I told her the usage went way up on that day she made the connection. The fact that there is activity pre-Feb 1 has to be because this device signature matches another device on the property?

When I’m home and see it running, I’ll unplug the fridge and see what happens.

That’s a lot for a fridge, but very possible. If you open your fridge and read the label it will tell you what the wattage or amperage is for the compressor and usually the heating element. Amps times current equals watts. 3.5 x 120 =420 watts.
I’m now curious if you’ll tell her she was right?

400W for a fridge; seems quite excessive. The compressor on the fridge would be 110-130W

Definitely a lot, mine is 93 watts for Frigidaire Gallery and it’s big. It’s 92 for a small chest freezer. Both are watts for compressor only.

Now that you mention it, I agree. 400w is a lot for a fridge. Also, I’m used to see a higher start-up draw for motors. 50w extra at start-up seems pretty low. Maybe that’s because it isn’t a very large compressor.

Our other fridge runs at 105w. We unplugged our mini-fridge because it was less efficient that the 105w fridge!

I will update this post when I can do some onsite detective work.

Take note that forcefully unplugging a device when it’s running may not provide sense with the normal “off” signature expected with a normal shut down, therefore Sense can sometimes continue to show the device running in the device view, even though it’s not…

Whenever possible, use a control on the device to turn it off as close to as what would be considered “normal” as possible, so it the case of a refrigerator, raise the thermostat to to trigger a “normal” off signature.

If you must unplug something for diagnostic purposes, you need to be looking at the “now” display (not the device display) to see if you got the expected wattage drop.


Thanks for that. I’ll change the temp on the unit and stop it that way.

I’m suspecting it could be your air handler blower motor.
Motors like that have a spike at startup similar to a
compressor but the spike is much smaller. If you have
a variable speed blower then it could draw that much
if it’s on the high setting. It would also cycle many times
an hour based on many variables and settings.
When i say air handler fan. I’m only talking about the fan
motor for circulation inside the house.
Typical cycles per hour for:
heat pump 3
Gas or oil 5
electric strips 9
But depends on how installer set it up.

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Hmm. I agree that the spike isn’t as high as other compressor motors. I was looking at the other fridge and it has a much bigger spike.

I’m fairly certain is isn’t an air handler though. We aren’t running any HVAC systems at all. One zone is out of service (oops, I cut the thermostat wire during construction this weekend!), one zone is powered off, and one zone is set to 60 degrees.

Just a quick update…

Short Version: I can’t find the device.

Long Version: I’ve spent two weekends at the breaker boxes on my property. I started by turning off the pool house (where we are actually living). The Oven persisted. Then I turned off the house (we are renovating). The Oven disappeared. I then turned on half of the breakers. Then the other half. When I found the Oven still persisted, I split in half again. I continued this “binary search” until I narrowed it down quite a bit, but I ran out of time. For now, I have everything except one AC unit breaker turned on. The Oven hasn’t returned since Sunday. Odd since this doesn’t make any sense. I left the AC unit’s breaker off because when I turned it back on I heard crackle/sizzle. I’ll be replacing it, I think. But, again, 400 watts isn’t enough for a 1+ ton AC unit that we actually have not been using at all (OFF at the thermostat).

I’ll update again if I find anything that’s interesting enough to share.

Oh, I did actually see a 1w “Oven” entry yesterday. But I have not seen its signature 451w or 401w activity since Sunday.

I still haven’t found what the Oven may be.

I did my binary search at the beginning of March. The Oven stopped showing up every hour for 20 minutes. It has only showed up 5-6 times in the past 2 weeks. In February, it showed up over 1,000 times! In the first three days of March, it showed up approximately 100 times. Now it rarely shows up, but it still does very infrequently.

All I did was turn off a bunch of circuit breakers whenever I saw it online. I never figured out what the device is and now that it doesn’t pop up as frequently it is nigh impossible to find.

If I do find it, I’ll update this thread.

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I echo what others said above, that looks very very similar to the fan in my HVAC furnace. 400 W, similar cycling, and similar starting spike. And it makes sense that it would change how long it runs, depending on how cold / hot is outside where this unit is.

Can you zoom in on just one instance catching the positive going side and the negative going side?

What do you mean by that positive/negative question?

The beginning and end of one on cycle

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I wanted to start with showing the last time the Oven was on a lot. You’ll see it stopped occurring all the time on March 3. There are five other days in March where it turned on at least once. The only day in March the HVAC turned on was the 4th.

The next screenshot shows a few months of on/off. If you were to zoom in far enough you’d see the frequency changed on February 1 around 2pm.

The next screenshot shows March 3 through to the last on/off.

The next screenshot shows what was requested… three on/off patterns.

I will do an HVAC fan test when I am next at home.