EnMo in Home Assistant

View water meter, heat meter and heat cost allocator readings as sensors in Home Assistant. You need an EnMo API key and a one-time installation of the integration.

Download the EnMo integration (ZIP)

Install in three steps

  1. Request access and create a key. If you are an end user assigned to an apartment, request API access by emailing info@enmo.sk. Once access is enabled, open Documents → Your API keys in the EnMo portal. Enter a name such as “Home Assistant” and create a key. Property managers can create a key without requesting access. The key is shown only once.
  2. Copy the integration. Download and extract the ZIP. Copy the custom_components/enmo folder to your Home Assistant configuration directory, so the file custom_components/enmo/manifest.json is present there. On Home Assistant OS, the configuration directory is usually /config. You can use the file access available for your installation, such as a network share or a file editor. Then restart Home Assistant.
  3. Add EnMo. In Home Assistant, go to Settings → Devices & services → Add integration, search for EnMo and enter the key. The first read starts after you add the integration.

What you will see

Each meter with a technical identifier appears as a sensor showing its latest valid counter reading. The sensor also shows the apartment's variable symbol (VS), if available, the meter serial number and the reading time. A counter reading is not daily consumption. A sensor is unavailable until it has a valid reading. A missing VS is left blank. Heat cost allocators use their own device units, not kWh.

The integration reads the API no more than once per UTC day. After the initial read, it updates daily at 06:30 local time in Slovakia (Europe/Bratislava). It keeps the latest valid snapshot across restarts, so repeatedly opening Home Assistant does not create new requests. If the connection fails, it displays the saved readings and tries again the next day. An invalid or revoked key clears saved readings from the integration and marks its sensors unavailable.

Security and help

The key is stored in your Home Assistant configuration. Protect administrator access and backups. The key is not included in the installation ZIP or the local reading cache. Use a separate key for this integration; you can revoke it in EnMo at any time. Removing the integration also deletes its local cache.

If the sensors do not appear, check the location of manifest.json, restart Home Assistant, verify the key and check Settings → System → Logs. If you have already used the same key elsewhere on that UTC day, EnMo may return the daily limit response; the integration will try again the next day. To change the key, remove the integration and add it again with the new key.

Developers and coding agents can use the API guide (in Slovak) and the OpenAPI description. Process apartment and meter data in accordance with your access rights and GDPR.