Prevent water line freezing in apartment garage

[garageman]

I am new here, so heres the question,
how do i prevent water line from freezing in apartment garage? the apartment above is the garage and the garage below is not heated. the water line comes from the house and must run to the upstairs apartment (about 4 feet of pex), water supply line comes from the side of the house and into the garage by the ceiling in the garage. it will be exposed and no amount of insulation will stop it from freezing, so my idea was to run it though a "send" heat duct not a "return" duct to prevent it from freezing. i checked all sorts of codes and not one one says i cant. so any better ideas out there? thanks

 

[Reach4]

Good closed cell foam insulation between the pipe in the garage, but not between the pipe and the heated space, will keep the pipe from freezing.

I don't know the allowably about feeding a pipe through a heating duct, but insulation between heating ducts and the garage would be worthwhile to prevent heat loss to the garage.

 

[Sponsor]

 

[JohnCT]

Good closed cell foam insulation between the pipe in the garage, but not between the pipe and the heated space, will keep the pipe from freezing.
.

A lot of people just flat out miss this. They might just read it as just adding insulation. That will only help over a short term if the water is drawn often. The trick is to heavily insulate the space between the cold barrier and the pipe, and *remove* any insulation between the pipe and the warm barrier.

Good post.

John