Using Home Assistant to save on electricity bill (and stop being an idiot)

Hi fellow HA geeks

Living in Europe in these days mean that your electricity and natural gas prices have more than doubled.
In periods prices increased by 500%. Only an idiot continues like nothing has happened. Like me - until September last year when I saw my electricity bill.

This thread is about my experience with getting my electricity bill reduced. I will post a little at a time so keep an eye on my postings and feel free to share your experience as well.

I say right away. If you are from a part of the world where electricity is still cheap - please do not comment with “eehhhh… it is only x cents per year. It is not worth the effort.”. In most of the world we pay a very high price for energy and as long as there is war in Ukraine, prices will remain sky high.

I live in Denmark in the area around Copenhagen. We all have smart meters that report consumption every hour and you pay prices by the hour. Where I live - before any money is paid for the electricity itself these are the tariffs and taxes we pay per kWh in February 2023.

  • 0:00 to 6:00 0.4665 DKK/kWh
  • 17:00 to 21:00 2.2735 DKK/kWh
  • Rest of day 0.8958 DKK/kWh
    This is actually around 1 DKK lower than is should be because from January to June 2023 the Danish government reduced electricity tax to near zero to help people financially in the crisis.

On top of the tariffs comes the actual electricity as it is traded on the Nordic electricity exchange and prices depend on wind, sun, and prices of oil and natural gas and they change by the hour.

So a kWh in the past year in Denmark has cost between 0.4 DKK and 8 DKK. As I write this 1 DKK is 0.14 USD or 0.13 Euros. So that sets the stage. If you live in a place where you pay a few cents per kWh - good for you. Shut up :stuck_out_tongue_winking_eye: The average price has been around 3–4 DKK per kWh

So. I am a small family. There is me and my sweet wife. No children or pets. We live in a small house of 103 m2 and we heat the house with natural gas. And I do not yet have an electric vehicle.

In the past years our yearly consumption has been close to 8000 kWh per year. My year electricity bill in 2021 was almost 20000 DKK and in 2022 it was heading for 30000 DKK. That is a lot of money. And then natural gas comes on top.

A normal family with 2 children and no EV consumes 4000 kWh per year. When I left my house Gretha Thunberg and a delegation from Greenpeace was standing with their signs that said “Environmental Pig”

Something had to be done. I had been an idiot too many years just letting the consumption increase and increase. And Home Assistant has not helped as I added more and more gadgets.

What do you do? I do not want to stop automating my house and I do not want to freeze, eat cold food, sit in the dark. But it turned out that the main reason the consumtion was 8000 kWh is because I was an idiot. And I bet we are a lot of idiots.

I started in September. My monthly consumtion can be seen here


The black dots are last years comsumption. Something dramatic happened in September. This is what this and following postings are about. It is a reduction by 40%. It is like 3000 kWh or 9000-12000 DKK per year. It is worth saving. That is a a lot of money. How did i do it?

If you read this - you use Home Assistant. And that is one of the tools you need to fight this.

You need to get something that can measure electricity.

You cannot take a multimeter and measure current and multiply by mains voltage. You get wrong and often too high readings because you then calculate apparent power. You need to measure the real power which is what private consumers pay for.

Then you need to start a spreadsheet. You need to register every consumer you have. Nothing is too small. Every wallwart. Every powertool charger. Electrical toothbrush. EVERYTHING.

Having an app where you can see your consumption is a good tool and a most have. But the problem with these apps is that the data is delayed by days. When you are working, you need data NOW.

Another important tool is to get a number of smart plugs that can measure and report power. Plugs that you can add to Home Assistant so you can see the consumption both NOW and over a full 24 hour period.

You will quickly find that your top consumers are

  • Fridge
  • Freezer
  • Stove/oven
  • Central Heating system
  • Electrical heaters for anything (floor/towel rack etc)

You are not going to stop cooking. Your natural gas furnace will still need to run. You still need to keep your food cold. There is a basic electricity consumption we all have. You can only do something about that if there is something wrong with an old fridge and you need to replace it.

You will find that a HUGE amount of electrical power is wasted by all your small consumers that are always plugged.

First you go to your living room. And then you look at your rack of AV devices. And you get rid of anything you actually do not use.

I had a VCR. Yes tapes. It was blinking 0:00. It is probably 10 years since we played a tape. It was consuming 5 Watts when turned off.
I had an antenna amplifier. The PSU for it was behind my shelf system. The antenna has not been used for 10+ years. There is nothing to amplify. In the bin with that.
Two DVD/Blueray players. One for region 1 and one for region 2. I have not played a DVD or BR in years. But they are turned on. Ehm. They were. Now unplugged. Several watts saved. Nothing lost
An Apple TV. I never use it. We use a Google Chromecast with Google TV. We love it. Apple TV turned off.
I had a Raspberry Pi running Kodi. Have not used it for 2 years. Unplugged.
Checked the TV. It uses nothing when stand by. No worries

Satellite TV box. A unix based (VU+ Duo). Power when on 27 W. Power when off 22W. Yes. 22W stand by. A little magic and Home Assistant logs into the Vu+ Duo and shut it down when we are done watching TV. Standby power now near zero. It takes 1 minute to turn on. We can live with that.

I play keyboard. I have two. Always on. MacStudio. On for days. External Audio card for Mac. Always on. Monitor for the music setup uses several watts standby. Put them all on a power bar. Turns everything off when not used. It takes a Mac 30 seconds to boot up. Not a problem at all.
An Apple timemachine. It is a bit like a NAS with a huge harddrive and the MacStudio backs itself up on that. Cool thing. Was on 24 hours a day using 7 Watts doing nothing. Moved it to the living room and on the same power bar as the MacStudio. Now it only runs when the Mac is on and can actually backup stuff.

An Apple Airport that I can Airplay to. Used to love it. Always use the Chromecast now. Removed.

A Raspberry Pi running a Squeezebox app for music. It is now controlled by a smart switch.

I already have Home assistant turning on TV, Amplifier, Sat receiver, etc etc depending on the mode you want and we press a button a Zigbee remote (or ask Alexa) and HA takes care to turn the boxes on and off and switch AV inputs (via Network or IR blasting from Broadlink). It was all there. It was just a matter to also control a couple of smart switches.

All idiot things right? Thinking - ah they only use a few watts. It is nearly nothing. NO! It adds up much more than you think because there are so many of them

My Workshop. A real DIY guy has power tools. And they have chargers. All the chargers used 6 Watts without having a battery in them. Just stand by power. They are on a power bar now that I turn on if I have to charge a battery which is a new hours per month.

I had some measurement instruments. A GPS locked frequency reference. A frequency counter with an oven. All turned off. I do not need the precision. And if I do - I can turn them on and wait a couple of hours. They also used many watts of power

My 3D printers are controlled by Octoprint running on a Raspberry Pi with LCD screen. Always on. 7.2 W. Now controlled by a smart plug which is controlled by Home Assistant. 3D printers and Octopi all controlled by smart switch. I print once per month for 3 hours. Rest was waste.

Each ESP8266 or ESP32 box consumed around 0.5-0.7 W. And I love them and I want to keep them. But I still had 4-5 I did not really need. And in some cases I could move a sensor to one of the others. I eliminated maybe 5 W of silly ESP devices.

I have 7 Amazon Echos. And 7 Google Homes. I always use Alexa. I never use Google Home. That was a tough decision. They consumed 64 W of continuous power 24/7. A major consumer.
I removed 5 of the Google Homes.
And among the 7 Echos, the one in the bathroom was silly and removed. And in kitchen, living room and office I had Echos with large displays.
I put smart switches on them. I turn them off when we go to bed. Or rather Home Assistant turns them off when both bed sensors register that we are in bed. And turn on when the first person enters the kitchen in the morning. They also turn off when we turn on the alarm system (which is Home Assistant). This is in no way inconvenient. But we save a ton a energy.

I added some mm wave radar sensors to the house. That adds a few watts. But they can detect presence much better than the PIR sensors can. With PIR you have to define time outs of up to 10-15 minutes to avoid light turning off when you sit or stand still. With proper presence sensing you can go much more aggresive with the timing and use 1-2 minute timeouts. That adds up to a lot of off time - especially at winter

How many computers do you guys have?

My windows laptop was always on. I just closed it. Now I turn it off. It boots in 30 seconds. Not a problem.

Our office machine was also always on. Now we switch it off when we are done and have a smart plug so we can cut away the 3W standby power it consumes.

Servers: That was really silly
I had a small Shuttle PC used as mail server.
I had a NUC running Deconz, Unifi, and Mosquitto
I had an Odroid running Home Assistant
I had a powerful PC running my webserver and camera NVR
I had another powerful PC running Linux in my workshop which I rarely turned off
I had a Synology NAS
I had 3 UPS for these
I had a MacMini that I used before my MacStudio on a shelf
I had a small dual core NUC on a shelf which used to run HA

So I decided to keep the NUC, the Odroid, and the Synology NAS.
I removed the power hungry PC and moved my Webserver and NVR on my MacMini. It used half the power and has no problem running these at all

The mail server was moved to the NUC and the Shuttle box was retired. The Linux machine in workshop is now turned off and the dual Core NUC is more than adequate for Arduino programming or ESPHome. And it is turned off if I do not use it.

And with the MacMini low power consumption, the NAS and Webserver could share an UPS. Removing a NAS removes 3-4 W standby power and one less battery to replace every 2 years.

The Synology had no power saving enabled and it actually consumes 0.6 kWh per day. If you enable hibernation on the drives, it consumes half when not used. But it often jumps out of hibernation. You can so something about that.

  • Make sure all your boxes incl Home Assistant run their backups around the same time every day. This way they share a common time out tail.
  • Remove your Synology integration from HA. Do you really need those sensors? HA wakes it up every 15 mins by default. This is really silly.
  • I now have Synology hybernate 60-70% of the time. Only downside is that you have to wait 10-15 seconds before it is available when you want to access it the first time. While you work on it - it is kept on so it is not really a problem. I save 109 kWh per year just on Synology
    I am thinking about replacing the HDD with SSDs. But it will take 30-40 years to earn the investment. That is silly. But when the HDDs reach the 3-4 year life I will replace them by a couple of WD Red SSDs

Network is a huge consumer. After I removed some of the silly boxes under the TV I could replace the 16 port Gigabit switch by an 8 port and that saved roughly 4-5 W of power.
I tried to remove one of my 4 Wifi access points and move the 3. I had to readd number 4 as I had a corner where my ESP devices would start disconnecting.

I have 7 Webcams. 6 outside (Ubiquiti) and 1 that films by 3D printer.
The one for the 3D printer now turns on with the Octoprint (same smart switch).
For the 6 Ubituiti cameras - they are all POE powered. And the managed TP link switch can be controlled by Home Assistant. So now HA will turn on 4 of the 6 camera only when we are not home. I do not need 6 cameras running when we are home. One at each door is enough.
That saves 16 Watts except the 8 hours a day we are not home.

The power consumption for the NVR (Frigate) goes down by 3-4 Watts when you remove 4 of 6 cameras from the workload. So the actual power saving with camera is around 20W 16 hours per day. 120 kWh per year just by turning cameras off when they are not needed.

I increased the temperature of the Wine/Beer Fridge 1 degree C. That saved a bit also. My beer is OK at 7 deg C instead of 6. Actually better!

I went through all Wallwarts. Most consumes nothing when idle per new EU regulations. But a few older uses 1-2 Watts doing nothing. I just replace them by other I already had. The old ones went for recycling.

As you can see the electricity prices in Denmark are really low at night. We started using the timer in the dishwasher so we start it at midnight. That does not save kWh but it saves money.
And we never do laundry between 17:00-21:00 now

All the smart lights use 0.25W standby. It adds up. But it only takes an intelligent use of HA automations to turn the light off when you are not in the room to more than compensate for it. I have been calculating in detail and measured on and off power and power at different intensities. It is not hard to save more than they consume in standby.

It is not nice to be in a house where all rooms are dark. A way to setup the automations is to turn off the high energy lights and leave the low energy lights on - or dimm the light.
In our kitchen - at night - instead of turning light off - we turn off the power hungry Philips Ensis and dimm the LEDs under the cabinets to half intensity. That leaves a kitchen that appears lit when we sit in the living room and you do not enter a doorway of darkness. It works really well and the consumption when we are not in the kitchen is 20% of when we are there.

I think this posting is long enough now.


  • Spreadsheet - register ALL consumers, estimate hours on and off, and power when on and off. Calculate their annual consumption based on this.
  • It is all the small comsumers that are always on, that eat a lot of kWhs. Do not mentally bagatelize this. Everything is important
  • You need to be able to measure actual power consumption
  • Use smart plugs and power bars
  • Let Home Assistant control power so things are only powered when you need them
  • There is a significant money to save
  • You will still consume power for fridges, freezers, cooking, and heating. You can check that their consumption over 24 hours are per spec for the fridge or freezer. It has to be really bad to be worth replacing these
  • You will still be cooking and ironing. Nothing to save there!

Take your loved one on a nice vacation for the money you save


What a story, I mean you have lots of equipment :slight_smile:

Similar story with me, live in NL where my electricity price is 0.82 euro (normal), 0.64 euro (off peak), and 3.04 euro gas per m3. I guess our prices are higher.

Thanks to the government, they put prica cap: 0.4 euro electricity per kWh, 1.45 euro gas per m3.

But, they are still expensive.

Our electricity usage 2 years ago were 4000+ kWh, then we started to cut it down, we managed to get it down to 3100 kWh. But, we should be able to get much lower!

I used just 1 Tapo P115 smart plug to measure all things we can measure, one by one, and monitor it for a day or two. Freezer, oven, etc. And we found for example underfloor heating pump takes 40w standby, small network switch takes 6 watts, etc.

Now, I run HA on mini-PC which only draw 5 to 6 watt, connected to a small switch (2 watts!!) to link to our Google WiFi network. We turned off lights when it is not needed, replaced with battery operated lights with motion sensor (temporary solution).

Last week, we finally installed solar panel, and luckily I was able to integrate with HA using HACS because the official integration is broken due to new firmware. It’s a big investment but for sure worth it because we still have net metering, to get back our investment bit by bit (expect 7+ years ROI lol).

So yeah, it’s a journey. Our “idle” electricity usage was 5.5 kWh and it is now about 2.8 kWh.
This is usage per day, by the way. We measured that by checking the electricity usage while we were on holiday (no one at home).

Next is to get airco because we don’t want to use gas for heating (hey! we have solar panel).
Next after that is to replace our old freezer + refrigerator (2 devices) with just 1 big refrigerator which will consume less electricity.

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Thanks for sharing.

I’ll share some back. As you confirm, you can make assumptions, but in he end, only a measurement is valid. As you indicate: you did find several small consumers that are not worth it to be turned off.

Chase the big consumers, chasing the small consumers may generate more discomfort than it’s worth.
Think: 1W = a rounded 2€/year (if it’s not 2€ now, it will probably be in the foreable future).

But yes, old appliances in idle mode are not optimised. Even your clock might consume more than you think. If your clock consumes 5W like the VCR, it costs 10€/year - a new one is gained back is a relatively small time.

A smart plug also consumes power (about 0.3W, so 0.6€/year) - consider if you have to control it remotely or not.

You can also save on power by configuring your computer (adjust frequency/disk) and a portable computer generally consumes less than a desktop computer.

Dishwasher: the ECO program is longer but actually consumes less!

Cloths Washing: wash at low temperatures when that’s enough. We actually pour hot water heated by our gas boiler directly into the machine: saves time (about 15 minutes) and electrical energy (heating+tumbler).

Ironing: we actually do not iron.

Cooking: you can use high pressure cooking or the microwave (you only heat your food). To heat up water, we use the boiler and then pour it in the pot (less heat lost during initial heating). Cover your pots and pans when cooking.

Avoid heating places you do not go in: we’ve added a few curtains - more effective than expected.

Further: measure the consumption of your fridge/freezer every other year. When the consumption is “suddenly” much higher it may have less cooling gaz - it’s probably time to repair or change it.

Mechanical air extractions: clean them. When dirty, they do not work as well and may consume more for less effective work.

Buy smart: I look at the consumption and add that in the balance to compare prices.

Monitor your consumption: if you have a rise in your averages, try to identify what changed.


Interesting story with some nice ideas

I would like to add my own findings on the journey to consume less.
I found 2 very useful components for home assistant that I‘m using:
Powercalc and the sankey chart.

I measured that constantly running stuff like router, fridge etc. once and added them as daily energy. My TV and the AV receiver are added as virtual power devices because I use their Wi-Fi for tracking if they are on, in stand by or switched off completely.
In case someone forgot to switch them off in the evening a script sends me a notification.
Washing machine etc is measured by smart switches to keep track of consumption.
As I have solar panels with a battery I‘m in the process of automating start of washing machine or dishwasher based upon excess power. For now I just have icon colors that signal enough excess power per appliance.
All is visualised with a sankey chart for kWh but I plan a second one real-time power.

I‘m still hunting some spikes in my consumption and plan to add some more smart switches for the oil heating pump which could be the last big unknown consumer beside the oven.
But saving oil is a complete other topic where I have no idea how to really measure it

I’m measuring my propane consumption by monitoring the furnace blower motor wattage. There is a high and low setting on my propane furnace, with high and low corresponding blower speeds/wattage. I know how much propane my furnace consumes at each setting, so I made a template.

And I also found the Sankey Chart to be quite helpful;

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Very interesting read, and this has inspired me to go around the house and track the energy use too! Getting solar panels next week, and want to make sure we are using the energy as efficiently as possible.

One question - I see you have Frigate, but you only turn cameras on when you are out. Does this not spam the logs with errors, and also increase the energy usage of the Frigate computer, as it is constantly trying to reconnect? I’m thinking of turning our indoor cameras off when we are at home, but don’t want to have the unexpected side effect of more energy use elsewhere.


Good question about Frigate

I used to use Motion before (I was the maintainer of Motion for around 10 years and wrote a lot of the code in Motion so it was a hard decision to change). And Motion would spam the log with messages about missing camera but not create a huge load.

Frigate is not bad either but I found that Frigate goes pretty quiet as long as you disable the “detect” and “motion” features for the camera. When you use the Home Assistant Frigate integration, two switches for Motion and Detect are created.

here is some of my code

I have a script that runs when I arm the alarm system. it does much more including closing curtains etc. I only included the camera related

    - service: switch.turn_on
      entity_id: switch.camswitch_2_poe_4
    - service: switch.turn_on
      entity_id: switch.camswitch_3_poe_3
    - service: switch.turn_on
      entity_id: switch.camswitch_5_poe_6
    - service: switch.turn_on
      entity_id: switch.camswitch_6_poe_2
    - service: switch.turn_on
      entity_id: switch.camera2_detect
    - service: switch.turn_on
      entity_id: switch.camera3_detect
    - service: switch.turn_on
      entity_id: switch.camera5_detect
    - service: switch.turn_on
      entity_id: switch.camera6_detect
    - service: switch.turn_on
      entity_id: switch.camera2_motion
    - service: switch.turn_on
      entity_id: switch.camera3_motion
    - service: switch.turn_on
      entity_id: switch.camera5_motion
    - service: switch.turn_on
      entity_id: switch.camera6_motion

And naturally i do the opposite when I come home

The 4 first that turn off the POE are SMTP switches

That was the hardest to do as I know nothing about SMTP. My switch is a TP link POE managed switch.

A switch is defined like this (I changed the IP). Here are only first two. They are all the same

The hard thing is to learn what a community is in SMTP and what to put in the baseoid and I would still not be able to explain how I got to it. Examples via Google, and some trial and error

- platform: snmp
  name: "CamSwitch POE 1" 
  version: "2c"
  community: HA
  payload_on: 1
  payload_off: 0
  vartype: "Integer"

- platform: snmp
  name: "CamSwitch 6 POE 2"
  version: "2c"
  community: HA
  payload_on: 1
  payload_off: 0
  vartype: "Integer"

But the Frigate part is easy. The switches are created by the integration and you just turn them on and off. And that seems to make Frigate very silent about things and not run large CPU loads retrying

You could probably do it even smarter by disabling the cameras and restarting Frigate. I am open to ideas but as I have it now I have a measurably lower load on the server. My Mac Mini consumes an average of 14 W with two cameras on and 17-18 W with 6 cameras on. Same Mac Mini also runs my website and i see higher spikes from Bing crawling the site than from the camera. Frigate with the Coral TPU uses an incredible low amount of resources compared to what Motion did.

That’s great, thanks for this. My cameras are Foscams so would need turning on and off by smart switches, so I’m looking into this.

Did some experiments with Frigate, and it doesn’t look like having more cameras increases the power consumption very much (even though processor use increases) so I may leave them as they are.

Interesting your points on your Synology NAS. I have mine setup with Surveillance Station and a Home Assistant Virtual Machine that I use for my VPN (Wireguard), Vaultwarden and Adguard. So it never hibernates! I’m going to remove Surveillance Station and put the rest on a Pi running HAOS, which will consume much less power.

Can you elaborate a bit on the furnace consumption template? Did you measure the consumption on your gas volume meter?
I’ve ordered a BBQKees Gateway

and hope to extract some usable data to estimate my oil consumption and overall oil heating usage.