Question

question 5
which of the following statements about air - conditioning ducts is false?
o they can use the same ducts as the heating system
o they cannot be flexible ducts
o they should be insulated where they pass through unconditioned spaces
o they should be larger than heating ducts in cold climates
o they can use returns made of combustible materials

Explanation:

Air - conditioning ducts can be flexible ducts. Also, returns for air - conditioning ducts should not be made of combustible materials for fire - safety reasons. In cold climates, heating ducts are often larger than cooling ducts as more air is needed for heating. Air - conditioning ducts can share ducts with heating systems and should be insulated when passing through unconditioned spaces.

Answer:

B. they cannot be flexible ducts; E. they can use returns made of combustible materials