UPC service down, reimbursed?

An hour's outage wouldn't be sufficient to ask for a refund tbh.

In IT (and other) service delivery, there's a concept of Nines which is used as a milestone against which a service's performance is rated.

In service level agreements, a company will often guarantee "three-nines" or "four-nines" uptime to their clients, and will pay a penalty if they fail to stick to that target.

Three-nines is typically the goal for business-important services. It's typically the lowest threshold at which an SLA is signed. So for things like leased lines, business services (i.e. €500/month BB connections) and so forth. Four-nines is typical for business-critical services like a big company's website.

For a service connection like UPC, which is not expressly critical, two nines would be an appropriate measure, if you were to take them to court for downtime. That is, if UPC could show that their service is available 99% of the time, then a court would be satisfied that they're fulfilling their service obligation to you, to within a reasonable tolerance, taking into account what you pay for the service. It is a practical impossibility for a service to be available 100% of the time, so a court would decide what is an "acceptable" level of availability and IMO in the absence of an SLA, 99% is more than acceptable for a recreational service.

I say recreational service, because it's none of UPC's business what you use the connection for. Whether a connection is critical to you, is for you to decide, not for UPC. If you decide that you need better uptime, then you must pay for the SLA.