Alternately, make or buy a cozy for your water bottle.
I have a full roll of reflectix insulation and duct tape.Would that help keep the water from freezing?
What about wrapping it around a drinking bladder and tube?
Mabey putting a hand warmer inside the insulation for overnight would help.
The tube always seems to freeze. I like having water ready to drink while on the move.
Any thoughts?