Can anyone point to resources, reviews or experiences on monitoring power usage in 240v ac (US)?
Looking at the new energy dashboard features …. I have opower integration of my electricity usage and a nice graph. However most of my power usage is from a heat pump, and EV charger, and maybe a garage heater. All are 240v, larger current loads. So the new feature is something about graphing device usage with overall usage. So that would be cool to add
I started searching online and it doesn’t seem especially positive. I see a few clamp meters with integrations but also see reviews that they’re not very accurate.
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Shelly EM Gen 3
I have a couple emporia vue (2’s) and for my electric clothes dryer I just use a CT clamp on each leg and sum them.
Within the vue esphome config:
# Combined Dryer Sensor - platform: template name: "Total Clothes Dryer Power" id: total_dryer_power lambda: return id(cir9).state + id(cir12).state; update_interval: never device_class: power state_class: measurement unit_of_measurement: "W" filters: *throttle_avgDo you need to cut the outer insulation off?How else do you get to both legs?Edit: I see, it mounts in the panel. Actually brings up a different challenge since my electrical has evolved over the years into multiple sub panels
The CT clamp reads the current without having to be directly connected to the wire. It just ‘clamps’ onto the leg and is non invasive. https://en.wikipedia.org/wiki/Current_clamp
Here’s one of my panels with the clamps on. The top clamps read total power, the individual clamps below are reading one leg each. for a 240v you need both since each leg is only supplying 120. My dryer also sometimes only uses 120v when it’s not actively heating.
I have two 150a panels in my house and I have 2 emporia vue 2’s one on each panel. I reflashed them with esphome so I own the data, it’s not going out to emporia. but they work as individual devices collecting data from the clamps.
For non 240 loads you could also use smart plug with power consumption if you’re just wanting to track that device. In my use case I am capturing all usage from the two big clamp at the top of each panel then each clamps usage which gives me an ‘untracked’ value also since I have more than 16 circuits in each panel I cannot track every circuit.
That’s an interesting idea - is there a guide for newbies? I’ve never done anything with esphome.
I had been expecting to use the total power from my utility but perhaps that’s a better idea: measure total power with the same tool as individual.
Right, a big part of the goal is to identify whether untracked is significant.
I believe this is it: https://emporia-vue-local.github.io/docs/tutorial/intro/
Outstanding, thanks
It’s been a little while but I did follow a guide for the emporia vue.
There are newer versions and other similar brands out there if I find the guide I used it will be fairly specific to this hardware (certainly the base code setup)
I will look tomorrow
Shelly pro EM50 breaker box monitor, or similar monitor system. Sometimes cheap, sometimes a few hundred USD. They’re are many other similar models. Can be even installed before the breaker box to monitor the entire home to check for independent electric usage against your power company bill.
I have this thing, if you didn’t find it in your searching. It seems accurate enough to me, but I’m not sure how I (or any other reviewers) would test that for certain. Guess I could turn off all but one circuit and put a kill a watt on a microwave or something. Whenever I’ve checked the graphs the readings make sense to me based on what was running at the time.
Maybe accuracy is not the right word: I see your point that it’s likely accurate enough. My concern was consistency.
The total power usage as reported by my utility is measured one way and these measure a different way. Any error compounds, and the goal is to graph them against each other. Is it enough to make an impact?
That specific product has two sensors. That means only one 240v circuit, right?
Ahh, yeah, I guess I haven’t compared it to my actual bill yet. I should do that. Have to wait a few more months for data to pile up as I just moved in. I will say, I don’t understand why it matters if it perfectly matches the utility company, what are you exactly trying to do?
And yeah, two sensors. I put it on the lines into my house as my main concern was going over 100a in the whole house, as my old house doesn’t have a main breaker. I do see now that you wanted to do a device-by-device breakout so that would require buying a fair few of these, and there’s gotta be a cheaper way.
I saw reviews where the clamps measured as much as 40% high. If my heat pump is 75% of my usage and it read that high, then when I look as a percentage of total use, it will be over 100% and my “untracked” usage will be invisible
I agree it’s expensive, but the emporia one someone else mentioned has more meters on one device. I do have smart switches which directly measure power consumption so lights are covered. I know there are outlets so I could probably cover things like a freezer if I wanted to. But there’s really only a handful of devices which use noticeable power
I have succesfully used a cheap tuya meter from aliexpress (white box with two clamps and two wires for voltage). With the official tuya integration you can monitor one device (or whole hose) but if you are willing to jump through some hoops and using local tuya you can get both measurements separetly. I also have a cheap aliexpress DIN style tuya smart breaker that works fine with tuya integration. And finally I have used a tplink kasa smart plug hs110 for 240V measuring (it is advertised for 120V in north america and it has 120V outlet. All of this in 240Vac 60Hz.
Accuracy for monitoring purposes is fine.
