#Help identifying "passive" power draw

1 messages · Page 1 of 1 (latest)

autumn sleet
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So, I have an Enphase solar system that's hooked up to HA that provides me most of my power use info, though I also have a couple Zooz Z-wave plugs that can read power usage on a couple of "minor" devices - bathroom space heater (almost always off), upstairs refrigerator (addition for baby food, currently off), and some fans.

Currently, we're in the "shoulder seasons" where we are neither heating nor cooling many days, and so I would have expected to see our power use diminish to below what the solar panels produce. This has happened in some previous years, but not so right now. I'd rather not buy tons of new power-tracking smart plugs for every possible culprit, so I'd like to know if there are any good ways to help work out why the power usage seems so high (around 23-27 kWH) without any major power draws.

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"Usual suspect" applicances:

  • Refrigerator
  • Basement dehumidifiers (two)
  • Deep freeze
  • Water heater

Less likely culprits

  • Internet router?
  • Pumps attached to water heater and downstairs HVAC unit to make sure condensation gets out of the house
  • Parasitic power draw?
vagrant wind
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do you have some daily energy plots from your solar system? the pattern of the consumption can sometimes produce a clue

autumn sleet
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I do. What's the best way to share them?

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I do see some peaks but their timing varies a little.

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A peak around midnight is common though

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vagrant wind
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Ah yeah I meant a little more fine grained rather than processed through the dashboard
Like I can get this from mine

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autumn sleet
split wind
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There are a lot of unknown aspects such as light, how the heating works and other devices that are always turned on

autumn sleet
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Looking at that regular power use I'm assuming it's the water heater, but would need more research.

autumn sleet
split wind
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I don't think it would be a water heater, they tend to not heat continuously

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What you could try to do is switch off breakers and see what reduces the base load

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My guess would be on circulation pumps/vents or fans/network equipment and pcs

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Maybe a fridge/freezer but they don't tend to use those astronomical amounts of energy

autumn sleet
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We have separate HVAC units - eight pumps and three compressors. While they've all been off during this period, I wonder if the compressors have something they do even when the pumps are off.

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They're still powered, of course, I mean I use Mitsubishi 2 mqtt and the pumps are all off at the moment.

vagrant wind
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Yeah that's an insane base load! My guess is that the nighttime spikes are water heater

split wind
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If the HVAC units have a duct style distribution/blower fan that might run even without it cooling or heating the air

vagrant wind
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Still... 1kW of blowing air is huge

split wind
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Well some of that load is what having stuff just takes

autumn sleet
vagrant wind
split wind
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I would go with the breaker test and see if that does some immediate change on one or multiple of them

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It's fast and somewhat telling, assuming you have somewhat reasonably allocated breakers

vagrant wind
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Yeah, probably the best idea.

autumn sleet
vagrant wind
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You don't have a hydroponic weed setup, right? :p

autumn sleet
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I do have a 3d print farm of sorts, 3 printers, but it has been inactive for this period as well.

vagrant wind
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Oh fun, what printers?

autumn sleet
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A thought occurs to me about our air filters. We do have several. When I get the chance I'll shut them all off too to see their contributions too

vagrant wind
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Nice mix. I have a elegoo Prusa mks3 and a voron 2.4

autumn sleet
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Btw I've been away from home but here's the result of shifting the "smart" dehumidifiers (plug and separate humidity sensor) to be less aggressive.

vagrant wind
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is that when it drops from ~ 1000 to ~700?

autumn sleet
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As a follow up here, I've installed a couple new z-wave smart plugs to capture more energy usage values. So far, I am noticing that my dehumidifers use more power than I had anticipated and the freezer and refrigerator actually use less.

I haven't had time to go through the full process of flipping my breakers one by one and checking power usage but I can do that in the next couple of days.

Another culprit I wasn't expecting: the water cooler we have is pretty inefficient.

vagrant wind
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interesting

autumn sleet
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I still have a couple things I haven't measured directly yet, like several UPSes, or can't, like the radon fan. The breaker test should hopefully provide insight there.

vagrant wind
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yup, be interesting to see the breakdown in the end 🙂

autumn sleet
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What's a good "target" base power draw? I finally had the time to try various combinations of breakers off last night. The biggest impact was some upstairs lights breakers that cover various miscellaneous uses and a breaker called "Air Handler." I didn't think we had an air handler anymore so that one was a big suspicious.

However, I didn't have any one slam dunk result when I pulled one breaker. In some cases power draw increased after pulling certain ones, which confused me.

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I can annotate this later.

split wind
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for what is good depends on how heating and air stuff works in your home
but generally 100 to 200w is fairly reasonable for basic fridge n water circulation n heating baseloads just for the devices

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youll add a couple pcs and networking gear that may be another 100-200w

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id guess anything below 500 seems reasonable excluding electrical heaters and aircon

whole wren
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Correct, for example my home's air-circulation system has a 0, 1, 2, 3-speed setting. At 0 it draws 0W, at speed 1 it draws 19W, at 2 it draws 48W, at 3 it takes in 119 Watt. So if your air system is somewhat automated, it may start at a higher setting, then later dial back the speed depending on f.e. air quality measurements. That could explain your higher usage after the power cycling. Same thing with f.e. a refrigerator, freezer or even a battery charger. The usage of such devices can vary over time.
When I started measuring my whole home usage, my nightly energy intake would be a little over 1kW!, now that I am measuring most devices and replaced some very heavy users (talking about you, wash dryer!) I am down to ana average of 180 - 250W during the night.
B.t.w. In my personal experience the values returned by my Enphase system, both power produced and power consumed, are +- 20 W higher than I would expect them to be comparing them to the values from my P1 meter and a zigbee power measuring device.

whole wren
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I don't have any air (de-)humidifiers, so can't say anything on those, but for me the biggest users are in fact our PC's (plus their screens). During summer fans take up a lot of our energy too. For example this summer, July 1st - September 30th shows this energy usage.
1: a single fan, which took 137 kWh,
2: a PC at 114 kWh (+ the screens for this pc are at 4th position with 59 kWh),
3: another fan with 67 kWh.
5: the first kitchen appliance, a boiling water device (Quooker), 59 kWh.
6: my air circulation system with 53 kWh,
7: TV with 52 kWh,
8: my intel NUC running HA, plus a router (1st floor) and some other peripherals 47 kWh,
9: dishwasher 46 kWh
10: Freezer 41 kWh
11: Electric cooking + ventilation (Bora) 35 kWh
12: Was dryer 33 kWh
13: Access point (2nd floor) + switch + some phone chargers 26 kWh
14: Screens for a 2nd PC 26 kWh (the pc itself is at 19th position with 15 kWh)
15: Fridge, 24 kWh
16: Router/Modem ground floor, 22 kWh
17: Oven/Magnetron 18 kWh
18: Another fan 16 kWh
20: The last fan, 15 kWh
21: e-bike battery charger 13 kWh
22: Washing machine 10 kWh
As you can see the washing machine didn't even make it into the top 20, even though it runs almost every day. This was not at all what I had expected when I started this monitoring!

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whole wren
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B.t.w. you really should install the PowerCalc integration. This will help you identify energy usage of many "passive" users. Some devices it will detect automatically, but you can add others too once you've measured their power draw using some meter (or look up their specs). Things like my switches, but also the energy used by my (power monitoring) plugs themselves take up a lot of energy too even though their power is not that high at all. But these are always-on, so they add up to your nightly power draw.

autumn sleet
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In the meantime I've been suspiciously looking at this old unused doorbell transformer. I'm pretty sure this is one of the mystery circuit breakers. Switched off and nothing else was impacted, so that's a little progress.

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autumn sleet