Ever talk to someone about home automation and they don’t see a clear way it can be useful to theme? Here’s an example where others in my family completely bought into the tools Home Assistant and some sensors can give you.
Last summer, we had two trips to our family cottage go badly with our youngest having an upset stomach. After the second trip, we threw out all the food we stored between trips (condiments and frozen food) on the off chance something had gone bad even though it wasn’t causing a problem for the rest of us.
I also took apart the fridge to make sure the fans and other bits looked good. They did! Now, this is a fridge from the 1970s, but something great about appliances this old is they really are tanks compared to modern ones. My LG fridge at home is only a few years old and it’s already had its controller board replaced.
I don’t have any photos of the fridge itself, but here’s the freezer unit after I took out the case and some pages from the manual and label. It’s a “Coldspot”, sold via Kenmore / Sears.
I did this work, didn’t see anything obviously wrong, and after all, the fridge was getting cold! But what if the fridge wasn’t working at times even when we didn’t have power outages?
I already had rtl_433 capturing weather station data into Home Assistant. I got an Accurite 986M fridge / freezer thermometer that worked on the same frequency and set up graphs and alerts.
Over a few following trips, things seemed OK. My kid wasn’t sick. The thermometers would show a quick increase in air temperature whenever the fridge was opened, but they recovered within an hour or two. There was one actual power outage where the temps confirmed we should throw out the food. It was pretty need to see the defrost cycle run every 24 hours on the HA graphs.
Last trip, we noticed after loading the fridge and freezer that both were having trouble getting cold again. A day later, we noticed the freezer had been set by someone else to the warmest setting (got to save on the power bill!). Yet, changing that didn’t seem to work either.
Note how the fridge (upper line, I know, entity names need some housekeeping) had a day that never went below 5°C.
By this time, we were about to head home, but we wanted to know if we needed to replace the fridge. Extra smart devices to the rescue!
I try to always keep 1-2 extra Zigbee smart plugs with energy monitoring. They’re just so useful! I was really happy with Sengled plugs, but they became unavailable in Canada so last round I bought the Third Reality plugs. We emptied the fridge and freezer, and I quickly paired a plug with zigbee2mqtt as we packed out.
Looking at the graphs over the next few days, the first thing I noticed was the fridge was never actually turning off.
The kWh graph showed it used 20 kWh in 3 days!
It did get to reasonable temperatures, but was using a huge amount of energy to stay there. Fridges of this era typically used around 2000 kWh a year, but that assumes daily opening and closings that this fridge wouldn’t have seen. 2500 kWh a year with doors closed showed something was wrong.
With this in mind, I turned off the fridge remotely, and it rapidly warmed up. Perhaps the insulation wasn’t doing it’s job anymore.
To finish this up, a few days later about an 8 year old LG top fridge was swapped in, and it got cold within two hours. Look at the incredible difference in slope on the kWh graph:
It’s on track to use less than a fifth of the energy, and we know this fridge is reliable.
Anyways, I hope this post shows one of the values of monitoring appliances with Home Assistant. If anyone else has experiences of detecting appliance issues with thermometers or metering plugs, I’d love to hear them!
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) pretty close to the fridge, so there’s a strong connection. Material of the fridge is not an issue. I even had the Aqara sensor in the deep freezer for some time, far away from any ZigBee repeater (at that time it was connected to the coordinator, a ConBee II) and it worked totally fine too.