On Dec 28, 6:25*pm, " wrote:
Hi,
I have several heat ducts from my furnace in the basement which run
parallel and in between the floor joists. The basement is unheated but
maintains a temperature of about 55 degrees in the winter. Should I
wrap the ducts with a reflective insulating material for that purpose
or just nail in insulation between the joists like I was insulating an
outer wall. Does it matter?
Richard

Since your ducts are up high in the ceiling joists, I doubt they
provide any heat in the basement if left unwrapped. I would wrap them,
especially if you also use your ducts for A/C so they don't
condensate.
If you want to provide heat in your basement, I would suggest cutting
out an opening on the bottom of the duct and putting in a register and
forcing the air downwards. Or you probably get better results if you
had a portable electric heater or electric baseboard heat down low on
the floor. Remember, heat rises.