How it works

Three steps, and you know where you stand.

Readings or bill inBy hand, by CSV, as a PDF from your supplier’s mail or automatically from Home Assistant.
Energietracker calculatesWith your contract to the day, with the weather where you live and with a forecast up to the bill.
You get answers and remindersBalance, deadlines, letters and notes under To do, and if you like in your calendar and in Home Assistant.

Answers at a glance

Every picture answers a question. From the sample households, all figures invented.

Is my advance payment enough?Is the bill right?Is switching worth it?What is coming up?Did the insulation work?What will next year cost?What if?How was my year?How efficient is my home?Is the prepayment enough?How do I write to my supplier?Does it work on my phone?

Gas in the sample household: consumption, cost, advance payments with balance, daily average and CO₂, below the balance on the day of the last reading and the expected credit. — 1 of 12Is my advance payment enough?**Balance per contract,** measured up to the last reading and expected at the bill, plus a suggested advance payment. See it in the demo

Check a bill for gas: per section period, readings, days, m³, condition factor, calorific value, kWh, price, consumption cost and fixed costs. — 2 of 12Is the bill right?**Check a bill** recalculates the supplier’s bill section by section and says “fits” or “check”, with reasons. See it in the demo

Tariff switch: expected annual consumption to copy, switching possible at the contract end and the last day to cancel. — 3 of 12Is switching worth it?**Tariff switch** gives the expected annual consumption for the comparison site, the switching date and the last day to cancel. See it in the demo

To do: open items with deadlines, notice dates, expected bills and the people in charge, with filters by kind. — 4 of 12What is coming up?**To do** gathers deadlines, appointments, recommendations, rights and mail in one list, also as a subscription in your own calendar. See it in the demo

Analysis: effect of the measure with consumption per degree day before and after, below the curves of consumption against degree days and the year-on-year comparison. — 5 of 12Did the insulation work?**The analysis** measures the effect of a renovation per degree day and says whether it is statistically supported. Used more, or just colder? Every month stands against its expectation for that weather. See it in the demo

Forecast: costs summed over the year and consumption month by month with a band, base case and scenario. — 6 of 12What will next year cost?**The forecast** looks up to 24 months ahead, with an uncertainty band and the prices that apply then. See it in the demo

Forecast workshop for gas, example cold winter: examples to click, controls for winter, saving and tariff, next to them the result with cost, consumption, advance payment and balance at the bill. — 7 of 12What if?**The workshop** runs winter, insulation, room temperature, tariff, PV, battery or a new heating through your own data. Every assumption is shown. See it in the demo

Annual report 2025: the essentials with cost, energy consumption and CO₂, below at a glance cost, consumption and bill. — 8 of 12How was my year?**The annual report** sums up the year for readers without a technical background: the essentials first, as a PDF to print or pass on. See it in the demo

Key figures: efficiency 2025 per utility with class, comparison with traffic light and the stock in the oil tank and pellet store. — 9 of 12How efficient is my home?**Key figures:** efficiency in kWh per m² with a class, the comparison against reference values as a traffic light and the stock in your tanks. See it in the demo

Tenancy in the renting sample household: expected costs, prepaid, a small credit likely, suitable prepayment per month, below sharing CO₂ costs with stage and landlord’s share. — 10 of 12Is the prepayment enough?**Renting:** prepayment against the expected costs, with a suitable prepayment per month and the split of CO₂ costs with the landlord. See it in the demo

Dialog Draft a letter, special termination: details from household and contract, below the preview of the letter and the buttons Copy text and Download PDF. — 11 of 12How do I write to my supplier?**Letters** as text and PDF, from fixed templates and your data. You send it yourself. See it in the demo

Capture on the iPhone: the sheet with meter reading, delivery, appointment and document, the tab bar at the bottom. — 12 of 12Does it work on my phone?**On your phone:** a tab bar in thumb reach, all meters in one pass, as an app on the home screen. See it in the demo

What you get out of it

The financial side, without promises: you see your own figures, no made-up savings.

No back-payment as a surprise. You see long before what the bill will bring, with a range.
Adjust the advance payment in time. If it is far too high, the request comes ready as a letter.
Find errors in the bill: quantity, price and fixed costs recalculated, a missing bonus stands out.
Work through a switch, with the prices from the second year and the last day to cancel.
Miss no deadline: notice and special termination in good time under To do and in your calendar.
Share the CO₂ costs as a tenant: with your own gas boiler the app works out the landlord’s share, with a letter.

For every kind of energy

Nine utilities, one way of calculating. In seven languages: German, English, French, Italian, Spanish, Portuguese and Dutch.

Gasm³ to kWh by effective date, bill check, weather taken out.
ElectricityPeak/off-peak, heat pump and wallbox, controllable devices, dynamic tariffs.
WaterDrinking water, waste water and rainwater, garden and hot water meters.
District heatingCapacity and metering charge as on the bill, bill check.
Heating oilTank log from deliveries and dipstick readings, stock over the year.
PelletsLike heating oil, in kilograms, the delivery invoice is the contract.
PV feed-inRemuneration per billing year, credits from the direct marketer.
PV generationSelf-consumption, self-sufficiency, battery, balcony plant, payback.
HeatConsumption report of the metering service, hot water, heat pump performance factor.

Where do you stand?

Pick your case. Each one leads to a matching sample household in the demo.

Home with heat pump, PV, battery and electric car

What does the sun bring, and what does the heat pump cost?
- Every contract pays only its share, also with heat pump and peak/off-peak.
- Self-consumption, self-sufficiency, battery and performance factor in figures.
- Quarter hours from Home Assistant, charging sessions from evcc: did shifting pay off?
The weather-based forecast for heat pump, PV and battery comes with v3.13, planned for 17 Nov 2026.

See it in the sample household
Home with gas, oil or pellets

Is the advance payment enough, and when does the tank run dry?
- Balance and expected bill, plus a suggested advance payment.
- Used more, or just colder? With the weather where you live.
- Tank log for oil and pellets, a new heating in the workshop.
See it in the sample household
Flat with district heating

Are the standing charge and advance payment right?
- Capacity and metering charge as they appear on the bill.
- Check a bill, section by section.
- Advance payment far too high? The request comes as a letter.
See it in the sample household
Renting

Is the prepayment enough, and is the service charge statement right?
- A suitable prepayment per month, an estimate from your meters.
- Share CO₂ costs with the landlord, with a letter.
- Deadlines for the statement and objections in your calendar.
The CO₂ split applies only in Germany and is not legal advice.

See it in the sample household
Your rights as a customer

Check, understand, know your rights.
- Seven checks under German law, such as a late bill or a missing bonus.
- Every note names the provision with its source and date.
- The matching letter as a PDF, the deadline as an appointment.
A note, not legal advice.

See it in the sample household
With your own AI

Ask your AI how electricity and gas are doing.
- The AI is the interface, Energietracker the file behind it.
- Every figure with its basis, the same figures as in the app.
- Off by default; changes only after you confirm them in the app.
Tested with Open WebUI and a local model through Ollama, other programs experimental. The demo has no AI interface.

See it in the sample household Connecting an AI assistant

Home Assistant and HACS

Home Assistant measures, Energietracker settles the bill. Contracts, advance payments and forecasts are added, while Home Assistant quietly delivers the readings.

Readings arrive by themselves, daily or per quarter hour, protected by a key.
As an app in Home Assistant OS: in the sidebar, with your users and in Home Assistant backups.
Sensors without a line of YAML: To do, next appointment and per meter balance, consumption, forecast and days since the reading.
Deadlines and new mail are sent by Energietracker itself as notifications.

How it gets into Home Assistant

Add the app: add the repository with one click, install and start Energietracker.
Add sensors: the integration as a custom repository, in the Marketplace (Home Assistant 2026.11 or later, connect GitHub once) or in HACS.
Send readings: under Connections › Home Assistant the templates are ready to copy.

Add the app to Home Assistant Open in Home Assistant Connecting Home Assistant

Still young: the app is marked experimental, the integration is a custom repository in the Marketplace or in HACS for now. It needs Energietracker 3.9.0 or later and Home Assistant 2026.3 or later.

Diagram With Home Assistant: smart meters, Home Assistant reads them and sends readings daily or per quarter hour to Energietracker, sensors, hints and appointments go back. evcc delivers charging sessions. Outside there is only the weather service with a rounded location, which can be switched off. — From the app’s setup guide, which shows six ways to work with Energietracker.

Why you can trust Energietracker

You do not have to believe anything, you can check it all. Here is what the app does, what it does not do and where that is documented.

Diagram Your home: Home Assistant, supplier mail, an AI at home and you talk to Energietracker. Outside there are only a cloud service, experimental and only when expressly switched on, and the weather service with a rounded location, which can be switched off. — **What belongs at home stays there.** By default only the weather sync goes out, and it can be switched off. Everything else you switch on yourself.

Your data stays with you. No accounts, no ads, no telemetry, no database, just JSON files on your server. README, Your data
Open source under the AGPL. At home it is yours. Under Settings › System a link leads to the source code of exactly the running version. Licence
Signed images. Since 3.10.0 every image is signed, keyless and in the public transparency log, and carries a bill of materials and provenance. Checking the image
Security with deadlines. Every Tuesday the latest release is rebuilt and scanned for known vulnerabilities. You report issues confidentially and get an acknowledgement within 7 days. Security policy
Legal sources with a date. Every provision with a link, the day it was read and how certain the statement is. The app never states uncertain rules. Legal basis
2,667 test methods in 3.12.0. Every new rule has a counter-test that breaks it. Calculations are checked by hand, and every figure in the README is tied to a test. CHANGELOG, Tests
Dependable interfaces. APIs, CSV formats and the backup format change only additively. Anything is removed only with a new major version and after notice. README, Status
An open roadmap with a rhythm. A release has one theme and comes out when it is done and tested, usually after one to three weeks. Roadmap
Ideas are assessed. Before each release what counts is benefit for many, closeness to the bill, effort and privacy. Declined ideas get a reason. Roadmap, Ideas
Limits are stated. Since 3.7.0 every release lists under “Known limits” in the CHANGELOG what it cannot do yet. The roadmap says what is deliberately not planned. Known limits

What leaves your home

Connection	By default	What goes out
Weather sync with Open-Meteo	on, can be switched off	your location rounded to about 1 km, once a day
Place search at Open-Meteo	only when you use it	the place you search for
Note about new versions	off, you switch it on	once a day GitHub is asked for the newest version number
Wholesale prices from SMARD	only when you tap	nothing of yours
Text recognition, evcc, Home Assistant	only when you set them up	only to your own services in your home network
Reading in the cloud, experimental	off, only an administrator switches it on	documents to the chosen service
AI interface (MCP)	off	only answers to requests with a key of its own

Fonts, Chart.js and PDF.js ship with the repository, nothing is loaded from a CDN at runtime.

What Energietracker cannot do yet

Weather-based forecast for heat pump, PV and battery: comes with v3.13, planned for 17 Nov 2026.
AI: tested only with Open WebUI and Ollama. Whether another program asks before applying a change is not tested; that is why by default you confirm in the app.
Rights under German law only. In other countries the app shows no notes on rights.
At home in Germany in substance: for eight more countries, profiles set currency, formats and weather. There are no efficiency classes there, and the app does not convert currencies.
Home Assistant: the app is experimental, the integration a custom repository in the Marketplace or in HACS for now.
iPhone and iPad are tested in the WebKit test browser, not on a real device.
Legal basis: before each release a person reads every line against the wording in force. For v3.11.0 that is still pending, as the page itself says.

All known limits in the CHANGELOG

Frequently asked questions

Do I need Home Assistant?

No. You enter readings by hand, by CSV or from your supplier’s mail. Home Assistant is one way among several, and the app runs fully without a single connection.

Does it cost anything?

No. Using, changing and passing it on is free, with no account and no fee. A coffee for the development is voluntary. Only if you connect a cloud AI may its provider charge you.

Where is my data?

On your own server, as JSON files, with a backup as a file. By default only the weather sync goes out, and you can switch it off.

Does it work with my supplier?

Yes, with any. You enter contract and prices yourself or take them over from the bill. No connection to the supplier is needed.

Do I need an AI?

No. The AI interface is off by default, and if you do not use AI you lose nothing. To read supplier mail you set up a service of your own; entering by hand always works too.

What does it run on?

On anything that runs Docker (amd64 and arm64), as an app in Home Assistant OS or on a web server with PHP 8.3 or later. You use it in the browser, on the Mac as on the iPhone.

Does it work outside Germany?

Calculating, yes, with country profiles for eight more countries. Efficiency classes and the checks of your rights exist only under German law.

Installed in three steps

Pick the way that fits your home. The same program runs everywhere. The image is built for amd64 and arm64.

Docker

on your computer, NAS or server

Start the container:

docker run -d --name energietracker \
  --restart unless-stopped -p 8080:80 \
  -v energietracker-data:/data \
  ghcr.io/bingerminger/energietracker:3

Open http://localhost:8080.
“Try with sample data” shows right away what everything looks like; your own data is not lost.

Running with Docker

Home Assistant OS

as an app with an entry in the sidebar

Add the repository with one click or enter the address under Settings › Apps › ⋮ › Repositories:
```
https://github.com/Bingerminger/energietracker-ha
```
Install and start Energietracker.
Open it in the sidebar. The first person to open it administers the installation.

Sensors as well: the integration as a custom repository, in the Marketplace from Home Assistant 2026.11 or in HACS.

As an app in Home Assistant OS

NAS and home server

Synology, Unraid, CasaOS or Umbrel

Synology: in Container Manager under Project › Create, choose a folder and paste the docker-compose.yml from the guide.
Start the project.
Open http://<NAS address>:8080.

Templates for Unraid, CasaOS and Umbrel are included. The Unraid template is checked against the format and the image, but not tried on a real Unraid server.

Synology, Unraid, CasaOS, Umbrel

Your own web server

Apache or nginx with PHP 8.3 or later, no Composer

Get the code onto the server, for example with git clone.
Set up Apache with the included .htaccess or nginx with the rules from docker/nginx.conf.
Give the web server write access to data/ and open the address.

Apache and nginx

Without sign-in, anyone who can reach the app can read and change everything. On your own home network that is fine. Before allowing access from outside, switch sign-in on. Security and network operation

One project, three repositories

Everything is public: code, handbook, roadmap and every change.

To read on

Demo in the browser Handbook Releases Roadmap CHANGELOG Discussions

Get involved and support

Energietracker is independent: no company behind it, no advertising, no cloud account. It is maintained in spare time.

A star on GitHub helps, just like bug reports and telling others. To the project on GitHub
Suggest ideas under Discussions › Ideas. Give existing ideas a thumbs up, so it shows what matters to many. Ideas
Report bugs as an issue, ideally with version, steps and an invented example instead of real bills. Open an issue
Security issues please not in public, report them confidentially through GitHub. Report confidentially
Translate and contribute: pull requests are welcome. A new language is mostly translation. Contributing
Support, entirely voluntary: if Energietracker helps you and you want to give something back, you can buy a coffee. buymeacoffee.com/bingerminger

Your energy costs under control.