Insulated AC ducts necessary?

[shmorrell]

Hi all - I really want to reclaim some of the storage space that’s taken up by all the ductwork for my fwd AC system. (The unit is under the head of the v berth and takes up half of the lockers it runs through) I’m wondering if it would be stupid to use uninsulated ducting. The aft system ducts are in the engine room, so it makes sense to have those insulated.

The issue may be condensation. And in Houston this might be significant, but not sure.

Or maybe there is a type of ducting that is better suited.

Wondering if anyone has tried other kinds of ducting?

Thanks!

Steve

[s/v Jedi]

Originally Posted by shmorrell

Hi all - I really want to reclaim some of the storage space that’s taken up by all the ductwork for my fwd AC system. (The unit is under the head of the v berth and takes up half of the lockers it runs through) I’m wondering if it would be stupid to use uninsulated ducting. The aft system ducts are in the engine room, so it makes sense to have those insulated.

The issue may be condensation. And in Houston this might be significant, but not sure.

Or maybe there is a type of ducting that is better suited.

Wondering if anyone has tried other kinds of ducting?

Thanks!

Steve

Yes you need insulated ducts. But you could build your own from rigid foam with aluminum liner as sold in sheets, making rectangular ones that have an equal cross section for flow but minimize space occupied in lockers. For example, you can make then narrow and wide.

This leaves how to connect to them… this is where 3D printing shines. I’m sure there’s services that can make the adapters when you provide accurate dimensions

[thinwater]

Originally Posted by shmorrell

Hi all - I really want to reclaim some of the storage space that’s taken up by all the ductwork for my fwd AC system. (The unit is under the head of the v berth and takes up half of the lockers it runs through) I’m wondering if it would be stupid to use uninsulated ducting. The aft system ducts are in the engine room, so it makes sense to have those insulated.

The issue may be condensation. And in Houston this might be significant, but not sure.

Or maybe there is a type of ducting that is better suited.

Wondering if anyone has tried other kinds of ducting?

Thanks!

Steve

Yes.



To avoid condensation you need to do one of two things, same as AC in a house with ducts in a crawlspace or attic:

• The insulation must have a vapor barrier and the vapor barrier must be well sealed to the duct at the ends (best for flexible ducting).
• The insulation must be absolutely non-absorbent (closed cell) and bonded tightly to the duct with no air space (best for rigid).
• Self-adhesive neoprene insulation tape is good for little spots on rigid duct (but not flexible).

A combination of both methods is usually required.