RFC 7368 for home networks recommends the use of ULA locally.

> A home network running IPv6 should deploy ULAs alongside its globally unique prefix(es) to allow stable communication between devices (on different subnets) within the homenet

> When an IPv6 node in a homenet has both a ULA and a globally unique IPv6 address, it should only use its ULA address internally and use its additional globally unique IPv6 address as a source address for external communications.