Hungry appliances

Sunday, November 12th, 2023 at 07:57pm

After working through the cost of heating water my next target of investigation was appliances.

I am going to consider a fridge (or also a standalone freezer) to be part of the background usage. It is an appliance that needs to run all the time and be reliable because I do not want spoiled food. I am not considering trying to control it, if it is using too much power then the option is to replace it with a newer more efficient model.

Some other large kitchen appliances are the oven and hotplate. I know how much power they use and I know that I mostly use them around lunchtime which is already in “off-peak” classification. The smaller kitchen appliances such as the toaster and microwave are not used on a regular basis so I am not going to worry about those. The dishwasher I will come back to later…

Appliances for entertainment such as the television and speakers are used for specific purposes. I should check their standby usage, but otherwise I am not concerned.

I know the computers and monitors in my study are a large portion of my regular power usage, but they are essential, either they need to be on because I am working from home, or they are on because I am using them for personal projects or entertainment.

So now we come to the washing machine and are back to the dishwasher. These two applicances have pumps or motors, but also heat water which takes a lot of energy. This has been in the back of my mind for a long time, so in order to find out I went to Bunnings and picked up a “smart plug” that also included energy monitoring.

It worked and I was able to get data into home assistant, but this device needed an account on a cloud service to be configured and then the home assistant integration hooked in via that. Not the self contained approach I prefer.

I have yet to return this plug to Bunnings, but I after seem a couple of mentions in forums and other loactions I did order two Athom plugs with AU sockets. Although I haven’t looked at Tasmota for a while I knew of it, and importantly I knew it was MQTT based which I liked.

It took a couple of days for them to arrive and I set one up for my dishwasher and other for my washing machine.

I estimate that I run the dishwasher every two or three days, and this is its power consumption on the “speed perfect” and “half load” setting:

These days with working from home I find that I am only doing a load of washing once a week for clothes, then a dedicated wash for sheets or towels. This is my washing machine on an “intensive” cycle which is what I use for towels:

Quite different patterns. You can definitely see when they are heating water, and I think the irregularity with the washing machine is due to how it is detecting the motor usage, compared to a pump in the dishwasher.

But what does this tell me? Not really much…

But what might I be able to do with this information? Maybe something…

One thing I can do for both appliances is turn off the power using the smart plug to eliminate any standby power usage. I could also use a schedule in home assistant to enforce the time of use, not allowing them to run at certain times of day.

Depending on how fancy I want to get (simple could be x watts used for more than y minutes) I should also be able to add some form of indicator to know if the appliance is or has been running. If for some reason I have started a load of dishes in the afternoon I don’t want to always kill the power at 3pm, I would want it to complete the cycle and then turn off the power. A more useful automation I could configure is an alert to tell me (and remind me) when the washing machine has finished, because while dishes are ok to be left in the dishwasher, damp clothes in the washing machine need to be taken out and hung up.

As usual with these things, as soon as I dig into one aspect a bit I being up more questions and possibilities…

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