Lined Duct vs Wrapped Insulation
Lined Duct vs Wrapped Insulation
(OP)
Good Morning,
A primary air duct (55 F) is going into a non-conditioned space, and after about 50 ft. in this space the duct feeds a series of discharge grilles which blow the cold air in to the space. What is the preferred type of insulation for this duct. Internally lined or wrapped on the outside? What about vapor barrier? Locaton is in the south.
Thanks,
A primary air duct (55 F) is going into a non-conditioned space, and after about 50 ft. in this space the duct feeds a series of discharge grilles which blow the cold air in to the space. What is the preferred type of insulation for this duct. Internally lined or wrapped on the outside? What about vapor barrier? Locaton is in the south.
Thanks,





RE: Lined Duct vs Wrapped Insulation
If this was not a hot/humid area, you'd go double wall with insulation in between the walls, you get the looks of the exposed duct and it will not sweat.
By the way, cellular glass does look good when well applied. Costs more but no headaches for your hot/humid application, guaranteed.
RE: Lined Duct vs Wrapped Insulation
Duct wrap versus internally lined duct just depends on the application and the engineer. Lined duct will be cheaper to install (only have to touch the duct once and don't have to wait on city inspections, etc); however, a lot of people now use duct wrap because it is easier to keep the duct clean. If the duct is exposed, lined duct looks better.
RE: Lined Duct vs Wrapped Insulation
Most important is to seal the metal ductwork.
Internal insulation gives the fringe benefit of sound and being easier to weather proof.
If it is not exposed to the elements have a look at kanuf kool duct system. I was impressed with it.
Take the "V" out of HVAC and you are left with a HAC(k) job.
RE: Lined Duct vs Wrapped Insulation
RE: Lined Duct vs Wrapped Insulation
Check your local codes for what is required in your area.
RE: Lined Duct vs Wrapped Insulation
2. Vapour barrier is mandatory for cold air ducts. Otherwise you will have inevitable humidity concentration on the outside of the duct as well as quick deterioration of insulation. If you select insulation specified as AC insulation (not heating systems insulation), it should contain vapor barrier on the outside.