No, not to run. The hub measures, computes and stores everything itself, and the app talks to it on your own network. There's no account and no cloud service in the path.
But it does need the right time, and that's what the internet is usually for. The clock decides two things: which hour, day and month each record is filed under, and which tariff zone — and therefore which price — applies to the energy being used right now.
How the hub gets the time
Over SNTP, from time servers: pool.ntp.org by default, with time.nist.gov as the backup. You'll find all of it in Settings → Time.
If the hub has no internet, you can set its clock once from your browser instead. That works, with one caveat: nothing corrects it afterwards, so it drifts.
Two settings worth knowing:
- Resync interval defaults to 3600 s. Keep it between 60 and 86400. The app accepts other values, but one outside that range turns time sync off after the next restart — a known issue, and an easy one to inflict on yourself.
- Changes to the time source, the servers or the interval take effect after a restart. The panel says so and offers Restart now.
Until the clock is set, costs can be wrong
This is the part worth remembering. A hub whose clock hasn't synchronized doesn't wait: it picks a tariff zone from whatever time it currently thinks it is. After a boot without sync that's somewhere near 1970 plus its uptime, so the zone — and the price charged — can simply be wrong, and those costs are stored like any other record.
So after a fresh install or a power cut, check that Settings → Time shows the clock synchronized before you trust the first figures.
The day boundary follows the hub's own time zone: set it correctly and your daily counters roll at your local midnight.