We have a new house and the heat has just started to come on during the night. The
Air vent in our room makes a loud clicking noise as it heats up and cools down. Is there
A way to STOP the clicking before we go insane? Thanks!

In a new house you always have the option of bugging the builder.

Or you could try working some graphite or even talcum powder between the metal vent and where it comes through the floor. It expands and contract with heat. Each tick is a small jump. Some lube, and it moves smoothly and quietly. Even wiggling it around may loosen it enough to move smoothly.