Power monitor outlet for refrigerator

I have been thinking for a while that it might be useful to plug my 'fridge into a power monitor outlet. It's been slowly getting noisier over the years, and I would like to see if the power use is also going up, thinking I may be able to anticipate when it's getting close to end of life.
Then it occured to me that maybe putting it on some sort of switching outlet is, perhaps, a little risky. What is the default of outlets after a power failure. I think all my bulbs default to On, but I can't see outlets designed that way since there is no way to know what will be plugged into them.
So, what is you experience with refrigerators on smart outlets? Do you have a solution to power outages (when it comes back on, of course)? Has anyone actually gotten any useful information from monitoring it's power usage?


Use the Zooz Zen15 which is appliance rated, where you can turn off the physical button, and set the power loss default. Study the manual below for parameter 21 and 30.


That looks like the perfect device. It's on the compatible devices list, reasonably priced, and designed for the job. Now all I have to do is decide if having a power monitor will actually provide any useful information (of course it will :slight_smile:)

Just noticed it's z-wave too, which means it won't interfere with Aqara stuff if I decide to go that way. I have one z-wave device now, which is a Zooz 4in1 motion sensor. It's pretty reliable, but occasionally (infrequently) the lights don't come on or have a delay, maybe this would help.

I just realize that I have a basic question regarding power monitoring. How is the data presented? That is, does the Hubitat record the data over time and provide a graph or table so trends can be seen? If not, are that apps that can be installed to do this?


I use a Peanut plug on our deep freezer to monitor power. I know Peanuts have had a spotty past but we have several of them in use and they continue to work great.

By default after a power outage it returns to the ON state.
I'm able to determine both compressor on/off, defrost cycle and defrost heater on/off from the amount of current drawn. A few months ago it helped me determine that my defrost heater was no longer turning on during the defrost cycle due to a bad temperature limit switch.


Sweet! How do you see the data? Is it a graph or table?

This unit is on ST, so its just in a log (either in the IDE or on the app). I've thought about exporting it to something else but hadn't had a need.

Power is measured in watts.

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Does the increase in power cause it to report, then it reports at regular intervals until the power goes back below a certain threshold?

It uses standard Zigbee reporting logic of minimum X seconds, maximum Y seconds with delta Z.

Which says "report at a maximum interval (Y seconds) unless a change in Z (measured in a base unit or percent) occurs but never more than the minimum interval (X seconds)".

The DTH I'm using on ST for it sets the min to 1 second, max to 600 seconds and delta to something pretty low to get small changes in current. It's actually too chatty and at some point I was going to tweak it but never got around to it. For a freezer it would be fine to only report changes every several minutes and only when changing by say 10W. With 10W you could see the lights turning on in the power updates.

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I have a couple of power monitoring plugs on devices that I want to remain on, so I setup a rule that turns them on if they turn off. This won’t help after an outage, but does help if someone turns it off for whatever reason…

Sounds like you don’t have much on your Z-Wave mesh, so you should be fine, but remember that power monitoring can sometimes overwhelm the mesh.


Is that just for z-wave, or does zigbee have that problem too?

That would make it very easy to see what was going on, and adjust it for 'chattiness'. Thanks.

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I have never heard this to be a problem for Zigbee, so I don’t know unfortunately…


Yup, I just checked and triggering if a switch turns On/Off is easy, but I didn't find anything for hub status such as a reboot. I'm surprised, I would have guess that for more advanced users this would have been something useful. Maybe it's hard to implement. I'll have to find the support topic and ask there.

I have that Zooz device to control a dehumidifier and it works well. I can't recall the way it reports as I never graphed it. It is VERY "chatty", though, and produces a lot of z-wave traffic because of the power reporting. I eventually shut off the reporting via configurations settings because I wasn't using the feature.

What I did, instead, was install an Emporia power monitor onto several circuits including refrigerators). It also monitors whole house electricity. For just a little bit more money, I can now monitor several circuits and the whole house, and graphing is included. Just a thought...


You can use: “Location”, then “systemStart” as the rule trigger within Rule Machine to ensure it is turned on with a reboot.


I use a ZEN15 to monitor my washer, dryer, kitchen refrigerator, and basement refrigerator. Have had great support from @agnes.zooz

Used to have an OLD 1950s Westinghouse refrigerator in the basement that was given to me by a neighbor when they moved. The kind that could trap someone inside. Our children had moved out years before, so that danger was not present. It kept everything colder than our newer fridge in the kitchen even though a thermometer showed they were both at the same temperature. Bought a ZEN15 and put the old fridge on craigslist the next day. It was on more than it was off. The fridge was really quiet but it was hardly energy efficient.

I use a ZEN15 on the dryer and washer coupled with rules that monitor power levels and alert me when the power drops below a certain level.

One thing I discovered. Don’t make a dashboard button for the fridge. I accidentally hit that when I was making a change and the fridge was off for about 3 hours. :grimacing:


How do u use a zen15 on dryer... dryers are either gas or 220

In your position I would purchase a Kill-a-watt meter. Plug the refrigerator in and manually monitor. This assumes the plug is not blocked by the refrigerator.

I've found this device surprisingly accurate and it totals the KW-hr internally.
I know it is not Hubitat capable but sometimes not everything is a nail just because you have a hammer.


I have a rule that turns the switch back on if it is turned off.


As Gomez Addams would say “capital idea!”