Measure home power usage per circuit

Forums › Home Workshop DIY › Measure home power usage per circuit

deadlyllama

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#288908 31-Jul-2021 10:25

I'd like to work out why my power bills are so high. We're in a new (to us) house so I can't say "it was cheaper last winter before the heat pumps were installed" as we weren't here last winter.

In ye olde days there were a few products out there with clamps you'd put around the wires in your switchboard to record power usage per circuit.

I'm casting around to find something similar I can buy today, and have hit a wall.

How would you go about working out how much power your HWC/heat pumps/etc were using?

Jase2985

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#2752906 31-Jul-2021 15:57

i use one of these on the mains circuit

https://efergy.com/engage/

I can see small changes in usage, even lights going on and off. i know what most things are based on the little bumps

Couple of example of the dashboard:

eonsim

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#2753060 31-Jul-2021 21:53

You can build such devices using ESP32's and clamp sensors.

A few examples:

https://savjee.be/2019/07/Home-Energy-Monitor-ESP32-CT-Sensor-Emonlib/

Or using ESPHome with HomeAssistant:

https://esphome.io/components/sensor/ct_clamp.html

fe31nz

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#2753078 31-Jul-2021 23:59

Our Panasonic heat pump in the kitchen reports its own energy use via the IntesisHome WiFi addon. It is currently doing nothing and reporting 5 watts and 833 kWh.

nickb800

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#2753133 1-Aug-2021 07:02

We use a Shelly EM3 for this - it has clamps for 3 circuits

Bung

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#2753135 1-Aug-2021 07:45

Have you already checked that your hot water cylinder isn't venting hot water continuously?

PolicyGuy

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#2753174 1-Aug-2021 12:23

Bung: Have you already checked that your hot water cylinder isn't venting hot water continuously?

And that you don't have a leak in the hot water system tank and pipes?
Even a drip, drip, drip let alone a dribble will waste tens of litres a day and send your power bill rocketing.

When in a long-ago life I worked for a Power Board / Lines Company, a very large proportion of excessive-consumption complaints ended up as plumbing problems :(

Edit: Typo

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chevrolux

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#2753229 1-Aug-2021 15:01

Shelly 3EM for sure.

Will monitor 3 single phase ciruits for you.

deadlyllama

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#2755632 5-Aug-2021 12:53

Thanks everyone for your advice. I've found a second hand cent-a-meter which can only monitor one circuit but at least that lets me measure the hot water cylinder.

mclean

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#2756076 6-Aug-2021 11:15

I think the Cent-A Meter thing doesn't have a logger, so it's not very practical for measuring total energy consumption. Also if you're planning open the switchboard to access the phase conductor then.... (you know what I'm going to say).

Presumably your hot water isn't separately metered, as that would easily solve that one.