Idea for poor mans heatpump power usage

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1

I have an old heatpump, which does not give me any sensor, escpecially not a sensor that would tell me when it runs or how much power it uses. But as the heatpump is the device, that a.) runs for a longer time, and b.) uses the most electricity, I had an idea where I could come close to the usage, which I am not able to solve on my own.

I noticed, that if the heatpump runs, the total power of the complete house is over 2500 W minimum. The idea now is to track the power without the heatpump power usage (so power is below 2500 W) and save somewhere a 30 minutes average. And if the power is over 2600 track have a new sensor called pmh-power which is (actual_power - actual_30_minutes_average). During the activity of the heatpump the 30 minutes average should not be calculated.

I digged into the helpers, but do not find a way to store only values if the “total house power consumtion sensor” is below 2600 W, and find a way to take the 30 minutes averate only taking into account the time where the heatpump is not running… I did not find which helper to pick, and how to adapt it to the “only add if above/below”.

Any ideas welcome.

thank you

Juergen

2

I am not sure how it is connected to power but you could use it with a powerplug that measures consumption, plugs are 5-10 EUR on Ali?

3

That was my first idea too. But you shouldn’t use plugs for equipment that is more or less permanently drawing high power.

A Shelly either in the distribution cabinet or in a external box.would be a safe solution. Not sure if the OP is able to do this himself.

Create a new template sensor that does the math.

Untested:

template:
  - sensor:
      - name: "pmh-power"
        unique_id: pmh_power
        unit_of_measurement: "W"
        state: >
          {% set total = states('sensor.gesamtstromverbrauch') | float(0) %}
          {% set avg   = states('input_number.pmh_avg') | float(0) %}
          {{ [total - avg, 0] | max }}
4

A plug is not an option for such device, but you might use something to measure power with a clamp. For example a shelly EM.

Your solution could give your a very general idea, but well, 2500 W could easily be reached with just a couple of power hungry devices running at the same time, such as a kettle, oven, washing machine, dishwasher etc.

5

I would be interested to see a proper/academic basis on using plugs or not, atm it seems an opinion. I have 4000+ W devices on 20A/25A plugs without any issues.

The clamp is a good alternative if one can split the cables at a good location.

EDIT: the OP states 2500W total (!) use to the heatpump is likely quite a bit less

6

Because of my inability to access information from my heat pump, I designed and built a Low Cost Energy Monitor

A lot of caveats! Particularly when it comes to safety. Mine’s been working for a couple of years with no problems. 2 years ago, when I built it, it cost under USD$20.

Works with MySensors Potentially it could run as a gateway to avoid the nRF24 radios. But then it would have to be plugged directly into your HA host or use a wireless serial cable.

7

230V sockets max amperage is 16A, and they are not designed for prolonged use with such power. There are 32A sockets for 230V, but it’s different design, similar to 3-phase sockets.

I don’t think a heat pump is connected to a 230V socket. Those devices can be 5 kW or more, and their power consumption is not constant. I don’t have one, but I imagine it’s hardwired, similar to how electric stocks stovetops are connected. I wouldn’t be surprised if they also took multiple phases.

I would never trust a smart power plug to be able to handle 20A or 25A. I haven’t seen any reputable brands claiming more than 16A and even that seems excessive for prolonged use.

8

In Germany a standard plug is 16A max - not for permament use but 1 hour with 16 A (see IEC 60884-1). Practical experience suggests 10 A or ~ 2,3 kW. There are special connectors like this one for higher power loads:

image
image450×450 32.7 KB

Probably easier to just insert a Shelly…

9

HI,
thank you for your answers. I am fiddling with this now since about 1-2 years. The IMHO main reason for not havong it solved is, that I never ever would work on the main power cabinet of my house. Call me chicken, but I know what is dangerous if done wrong.
So I was searching for any professsional elektrisho, that “simply” installs this:
https://www.shelly.com/de/products/shelly-pro-3em-3ct63 (e.g.) in the main power cabinet to get it done. But before getting an electrician, I would have had an appointment with the pope. This is, how the heat pump is getting the power:

dont-fiddle-with-main-power
dont-fiddle-with-main-power1600×2080 264 KB

So no chance to have a simple plug, and no way for me, to fiddle there. Why I am now at a “reasonable good” software solution are these two screenshots:
typical winter day:

typical-winter-day
typical-winter-day1910×944 150 KB

typical summer day:

typical-summer-day
typical-summer-day1878×976 178 KB

I really do not care about all the little stuff, that I am using, as I would have to add power detectors at least for every room (which I won’t do, as I would have to fiddle in the main power cabinet), OR have every power plug in the 25 year old house attachted shelly. And yes: It was a MAJOR stupidity 25 years ago, not to have somting installed like a bus system and use HomeAssistant back than :slight_smile: :slight_smile:

So if any electrician close to Karlsruhe/germany is interested to get this small contract and write an invoice, I am open for this, please send a direct mail.

Any other solution should be possible, with not fiddling with the power cabinet, where I do not see the slightest chance.

many thanks for reading till here.

Juergen

10

HI,
OT tried to explain, that the sensor should react to “above 2500W” and below 2500W as this seems to be reliable enough to destinct between heatpump is running and heatpump is not runnig. My major problem is, that I need to collect the data only if this “above 2500” it taking more than 15 minutes (e.g.; maybe 30 is better), where I do not see a way in the helpers.
I quite successfully used some statistical helpers, to see if a device is “really” running, or just fiddling around a few minutes, like detecting if the washing mashine is done with washing and only swinging the the laudry which takes 10-20 minutes, before it really goes off. (We wanted to know when washing is done, so we could change the laundry, and be informed than, and not when the washing mashine going fully off; to save us some minutes :slight_smile: )

And if I notice during the process, that 2800 is the correct value, or what ever, than I could use this.
My major problem is, that I need something like:
If average of house power usage is above 2500W (e.g.) for more than 15 minutes, than use the difference from “Now-15 minutes before” and assume that this is from the heatpump (knowing that the parallel running coffee mashine will “ruin” my perfection :slight_smile:
With my knowledge I have about helpers, I do not see a way to do this, this is why I am asking.
Problem could also solved with some hardware and a professional electrician, but I could now find one, that is interested in such a small job close to Karlsruhe/germany.

Juergen

11

Hi,
as far as I understand this sensor, it depends of input_number.pmh_avg which is IMHO the sticking point, as I do need the average without the heatpump, but the sensor.gesamtstromverbrauch contains the heatpump as well, so if the heatpump runs (which is does usually for 15+ minutes) it would add to the average of input_number.pmh_avg if input_number.pmh_avg is calculated. But maybe I just use the daliy summer average as a fixed value for input_number.pmh_avg; but I was hoping to get “closer” to the reality.

I was hoping to distinct this (winter, but with exact minutes data)

SCR-20260212-jsgf
SCR-20260212-jsgf2502×962 173 KB

from this: (summer but imho with hourly data only)

SCR-20260212-jszp
SCR-20260212-jszp2532×1012 114 KB

many thanks
Juergen

12

No, this would be a constant that you set only once. I simply had it as a helper in the template code for easy update. The calculation can as well take place in the template with a number instead of a helper.

13

What I’ve done in similar circumstances.

a) use a smart thermostat - as it will tell you when it’s heating / cooling or idle
b) create a template that reports the heat pump power when the thermostat is in heat mode. As an example, I empirically calculated that my furnace uses 1600 watts when running. So make the template return 1600 watts when thermostat is on, else zero,
c) setup an “reimann sum” calculation and a utility meter.

That’s the basic simple setup, then you can improve (b) based on real measurements or more advanced models rather than returning a constant.

14

How does it know that? The heat pump is not visible to HA?

15

I’m thinking you could probably make a Time Simple Moving Average filter, then make another helper that would save this average power sensor value at the moment when power goes over 2500 W. You don’t need this helper to be updated any other time, just when the pump starts heating. This value would then be used for the heatpump power calculation (current power - the saved value, but only if current power is over 2500 W).

Edit: although, no, I realized this would produce wrong results if the pump started within X minutes since it was last on…

16

I used Shelly Pro 4PM in the distribution cabinet to measure the heat pump consumption and through it I monitor the consumption of hot water heating; 3D printers; sockets for PC audio and lights; and the last output to the heat pump. Basically, I use this element only to measure the consumption of these circuits. I just added a thermal fuse to automations.yaml to turn off in case the Shelly relay overheats.
Regarding the heat pump, I want to make an independent ESP32 control, but I don’t have enough information about connecting it to the Toshiba unit yet. Then I would expand the integration into HA.
I have the problem that Jürgen Egeling describes on the hot water heating side, where there is also a washing machine. I will solve this using the current value per phase at Shelly and switching SSR If, than off xx…

17

First off, you are a very wise person to be afraid of fiddling in the main power cabinet. Before I open mine, I perform a sort of Zen Meditation to get my focus on what I’m doing. And even though everything may be turned off, I assume that every wire, insulated or not, while shock the ever-lovin’ sh*t out of me. So, yeah, if you don’t have 100% confidence in yourself, stay out of there.

I have read about software that uses AI to determine what devices are turned on just from the data from meter of the main panel. Paraphrasing that sentence in to a search question yielded: Sense. You should look into this.

18

How about mounting a vibration sensor to the heat pump to detect when it is running?

19

:slight_smile: I tried this with no luck, as it was hard to get the vibrations without having false positives. I tried two different. One was aoetec, and the other I cannot remember. Same here: I did not want to open the heatpump, and the body is very well isolated agains vibrations and loudness.