Using Home Assistant with a cellular / mobile USB modem - Anybody doing it?

Anybody using Home Assistant and a cellular data modem? Does it use a lot of data?

I have a house with no internet that I’d like to put a basic installation in to monitor the temperature and toggle lights - This doesn’t sound like a lot of data, but realistically, how much data IS it? Any caveats or pitfalls to look out for? I assume I’d almost be required to use nabu casa to bypass all the CGNAT problems, and IPv6 sounds like a rabbit hole I don’t really feel like going down, plus setting up firewalls and security stuff I have no idea about.

You can use cloudflare tunnel for remote access.
I’m using a router with 4g modem since last year but i’ve never really checked the usage since I have an unlimited plan.

One guess … likely less in an entire month than you would use watching one movie. Stats from one of my tablets mounted in home network but still valid:

Wi-Fi data usage: 4.05GB used May 31 - June 28

And that pad is active 8 - 12 hours/day and is used for music so cover art for songs are constantly changing. And of course while it is really 100% Home Assistant, there are still things like updates, notifications, etc. through Android that have nothing to do with Home Assistant.

At any rate, one HD Movie is 4GB. SD Movie probably 2GB. Binge watch Sopranos … look out. Any 4G plan even throttled would be fine.

Just a data point for you.

I live on a mountaintop in the middle of nowhere. My only choices are DSL and Starlink. No Cable. But I can get 4G or 5G because I am so high up however I also have video-game kids who stream YouTube constantly and a wife that lives her Netflix. I chose Starlink (with 4G backup in case) because I cannot handle being throttled. Right now my Starlink is running 112Mbps. And 5G is running 263Mbps if I need it.

Do the initial installation somewhere else to save some data and avoid using to many cloud services.

Same here. Very successful so far, and (in the UK) much cheaper than a regular broadband contract.

Caveats and tips (sorry if you know all this already).

The key factor is the quality of your signal. As with a mobile phone, you’ll probably get different results in different locations round the house, but if you haven’t got a decent signal in the first place it isn’t going to work.

When you get a SIM, make sure it’s unthrottled. Most phone companies in the UK throttle data SIMs intended for mobile phones to reduce network loading.

Mobile speeds fluctuate much more than regular broadband, depending on time of day, the number of people on the network and even the weather, so when you’re testing you need to look at averages over a period.

Work on local masts is more likely to cause an outage than work on your local fibre network would (I suppose there are fewer fallbacks). Having said that, all the outages I’ve experienced so far have resulted in dramatic speed improvements, so I’m not complaining. At the moment, with a 4G+/LTE router I’m occasionally touching 70 Mbit/s, but the average is 30-40.

At very low speeds (less than 10 Mbit/s) HA integrations which use cloud services may time out - Alexa and Google, for example. They recover without intervention, but it means more log messages than usual.

Nabu Casa works fine.

I would probably go with a 4g router rather than an usb modem.
It means the modem can be placed where it makes most sense and HA where it .aked most sense.
It also means you can connect HA to the modem with a standard ethernet cable or WiFi and thereby avoid issues with usb drivers.