I have a house that is about 80 yrs. old.
The previous owner had a central air and heat system
installed for use on the bottom floor all the ducts
run under the house and through regestor in the floor.
I want to replace the galv. dusts with PVC since
these will be exposed to out side temps. will I need
to insolate the pipes and what is the best grade
os pipe to use? I will be skirting the house after
all the repairs are complete also...LL