7 - Chic, good looking
You will be proud to see and show it and won’t want to hide it.
Copper pipework performs excellently when hidden from view behind walls and under floors, but don’t worry if you are unable to conceal the pipework, simply surface mount the copper and leave it visible - everybody will appreciate it.
Thanks to the small outside diameter, low thermal expansion, great mechanical properties and attractive appearance, copper tubes can easily be surface mounted. Competing materials will not look so appealing.