Will SmartSense Temp/Humidity Sensor work from inside a fridge

It’s funny you say that because I did blame the kid first. I was not pleased. Cow blood from frozen livers everywhere. It didn’t need to be upright because it was frozen! The wife admitted it was her, so I had to apologize to the kid.

If the fridge light changed color from green to red as the alcohol supply dwindled…


I’ve had a Multi in my upright freezer (runs ~-10F) for 11 months with no range or battery life issues. It’s closely paralleling the other Multi’s battery life (down to 50% after 1 year), and it has about 35’ and 2 walls to pass the signal through. Works great, should work for you!

now my sensors tell me that my fridge is dying. 4KWH a day, running about 90% of the time, and testing shows it’s not leaking thru the seals. It’s 18years old anyway.

It’s nice to have some early warning so we have time for an orderly replacement without screwing up some food.


Are the coils on your fridge caked with dust? A good cleaning often solves a lot of fridge issues.

I looked, they’re not too bad, and less dust than when it ran 33%.

It is possible that the drain is blocked or frozen so I will take off the freezer panels off and look.

Those with a metal fridge, behaving too close to a “Faraday cage”, may instead of using the SmartSense Temperature sensor, use instead a Fibaro FGK-101\US outside of the Fridge and connecting the optional DS18B20 temperature sensor with a long 3 leads (flat) cable going inside the fridge.

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After cleaning and lubing the door gaskets, and raising the freezer temp, and summer temp/humidity has abated, now the duty cycle is about 75% at 3KWH/day. So it’s stage2 fridge cancer, down from stage4. I flushed the drain, it may have been slow but not blocked. High humidity may have caused an ice dam for a while.

The fridge makes a terrible Faraday cage.

@ero4444, what are you using to calculate a duty cycle? I have an Aeon power sensing switch connected to my beer fridge, but it doesn’t report duty cycle - just instantaneous draw and total kWH. Is there a smart app out there somewhere, or do you do custom logging?

For me it’s manual number crunching using power data from the ST log. The AEon plug-in logs a good running KWH (actually too often). Logging for 2 or 7 days would be better than 1. Determine the average power (Watts) of the fridge when compressor is running - mine starts around 200W and quickly decays to 175 and slowly to 165. Eyeballing the graph I use 175. Occasionally I see peaks of 500 which is the defrost cycle, which is brief and the frequency depends on how often we open the fridge door.

Divide the Watt-Hours (1000x KWH) by the chosen average Watts, that is the runtime in hours, neglecting the effect of defrosting and “moisture control” heating and lights, etc. Divide runtime hours by the elapsed time, and that fraction is the duty cycle.

An app would enable automatic notification of refrigerator health - a good idea. It only has to run once a week or less.

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Eric, if you don’t mind my asking, what’re you using to get the power data?

I tried using a Aeon DSC06 but the in-rush current drawn by the freezer was just too much for it to handle. The compressor would never start. It’s an older model fridge, so I’m not surprised it’s compressor might be less-than-efficient.

I have the Aeon clamp-around energy unit but wouldn’t mind something less massive. Ideally something that just plugged in-line or as an outlet module.

The Aeon DSC06 is rated to 15amps - that’s what I use now. It stopped your compressor?! Weird,unless it’s commercial/big . No that’s just weird. Don’t try to restart the freezer immediately after stopping it - let it sit 10-15 minutes at least to reduce startup load - or longer.

I have a residential fridge-freezer I think 21CF, less than 2amps when cooling. Before getting ST, I used P3 Kill-a-watt plug-in power meter which does KWH totalization and other things. I expect it’s only rated for 15A also.

If your freezer is really that old then it’s probably quick payback to replace it with something efficient. Might get a utiltiy rebate too

Agreed, a more recent unit would no doubt be less inefficient. This one isn’t broken and there are easier “explain this to the wife” arguments to be made. But I’ll keep an eye out for sales.

I have a Kill-a-watt lurking around in a box somewhere. Does it have the ability to track highest amp draw? As in, the in-rush pull from the freezer? Either way I’ll dig it up and put the freezer on it, just to see what it’s drawing.

As for compressor start-up, yes, that’s pretty much how I tested it. When plugged into the wall the compressor clicks and then starts running. When plugged through the DSC06 it clicks but doesn’t start. Tried it several times and got the same result.

I’ll get that Kill-a-watt out and see what it reads both with and without the DSC06 in the circuit.

A bit of searching on inrush and starting current reminds me to put a “I wanna buy an oscilloscope” on my Wish list…

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I use these in 5 separate freezers … working great… uses aa batteries… I had to replace in only 1 of them in 4 months…

I modified/wrote the device type myself…

youll have to hunt around to find them as not on amazon any longer…

After having an issue with our fridge/freezer earlier this week (and having all of our Christmas food spoil…), I decided to try a SmartThings Multipurpose Sensor in our fridge and freezer.

I haven’t had any communication/signal problems at all, although my fridge is only around 30 feet from my hub with 1 wall in between.

I’m not convinced the SmartThings Multi sensor reports temperature accurately once it gets below 32°F though. The sensors seem to work fine in the fridge (±2°F from my digital and analogue thermometers at normal fridge temp of around 38°F), but the sensor seems to be way off in the freezer (by 10°F or more once it gets down near 0°F).

Now I can’t really blame the sensors to be honest, the tech specs clearly state an operating temperature of 32 to 104°F, but I wanted to make everyone aware of this potential limitation (or at least my experience). Although the sensor might be reporting temps from your freezer, make sure you check those temps against a known good thermometer before you trust the numbers…

I’ve also hooked this stuff up to GrooveStream for trend analysis too. It seems to work well. GroveStreams SmartThings QuickStart

Just mounted the newest generation of SmartThings multi sensors inside my refrigerator and it’s repurting fine but wondering if anyone’s got any tips for lining up the sensor to mount as a contact sensor too. Hard to do when you can’t see inside the refrigerator where it’s being mounted.

trial and error. Don’t crush your plastic fridge interior, it might just crack.

I put the sensor near the hinge wall side, where they are less likely to get knocked off by fridge intruders. The magnet goes on a shelf support.

I just bought 3 of these sensors and was wondering how you set them up in smarthings?

mine are ordinary zigbee door contacts that also report temperature. The default detected device handler was fine without changes. Centralite something/ Bestbuy PEQ 3? type (out of production I assume)