Describe the existing system
Record the heating-system type and the model you are considering. An installed bypass system is different from putting a portable appliance in a room.
Ask practical questions
Discuss water supply, drainage, controls, access for service and replacement media with a qualified installer. Request a written scope covering the equipment and the work included.
Keep the documentation
Keep installation and service records privately. Share general ownership experience without publishing access details or private building plans. A room-volume tool cannot commission an HVAC system.