Ductwork through crawlspace

[billybarty]

I am planning on closing in a room under my cabin and insulating it and putting all my plumbing and heating items in there. I am building on a 2 story addition for bedrooms and am concerned about the bottom level being too cold. I have a wood stove that heats the upper level and would like to keep it. So I am concerned about the 2 zones I will have and would like to know a ballpark figure on the cost of doing 2 zones. The cabin is skirted and it is insulated but the floors are very cold in the winter. If I run the ductwork through the crawlspace should I use the insulated flexible duct or regular duct that is not insulated to help keep the floor above warm? There are some pretty tight spots to run the ducting and any tips are appreciated.

[CrashLanding55]

If your crawlspace is an unconditioned space the ductwork will need to be insulated and you'll probably will still have cold floors on really cold days. If you insulate the crawlspace and make it a conditioned space, like a basement, the ductwork will not need to be insulated and your floors will be warmer. Years ago builders tended to make crawlspaces unconditioned, like an attic but rooms above a crawlspace will be warmer if a crawlspace is made a conditioned space and it doesn't communicate with the outside.