The keychain is a crypted storage used to store passwords. It’s a major protection element of your device. iCloud synch is an optionnal feature ensuring that all your devices have access to the same keychain.
HomeKit requires home devices to use crypted connections to protect your confidentiality. You would not like entering a password for each device each time you use it. This is why keychain is particularly usefull. To be able to automate your home from all your devices you need iCloud keychain synching.
Home invitation is still an experimental part of HomeKit and will likely need more iOS update before beeing fully satisfying.
To make sure home invitations work properly take care of the following points:
- Do not cancel an invitation if the result is not immediate. Invitation mecanism seems to need up to 24 hours to complete and cancelling and sending again might interfer.
- When receiving the same invitation on several devices make sure to accept on the one most aften used for HomeKit.
- Avoid sending invitations to the same person using different email addresses.
After loggin into iCloud how HomeKit need several synchronization over 24 hours to display existing homes.
Even if not documented from HomeKit site, this seems like a security mecanism.
Make sure also that you completed all steps of iCloud keychain synching.
Any accessory can only be attached to a single home and a single room.
To move from one room to another of the same house, remove it from room 1 then attach it to room 2 using ‘Rooms’ tab.
To move from one home to another, unpair the device from home 1 then pair it to home 2 using ‘Accessories’ tab.
Please note that device unpairing will remove all accessories of the same device. This can occur for example when using hubs such as Phillips Hue or Nanoleaf.