Look up Unifrax it is ceramic fiber blanket material that can be glued on or if the conditions are extreme it can be "bolted" on

What are your cold side/hot side conditions?

There is a product, here in the local market known as AstroFoil, which is essentially bubblewrap with a laminate of aluminum foil that is quite effective. I believe it comes from the US. There are most likely other brands of this type of material as well.

The duct liner is called "Astro-Safe". and uses cotton fiber insulation lined with aluminum foil. I've never used it, but it looks good here:

http://www.jupiterheating.com/astro-foil-insulation/astro-safe-duct-liner.html

Check Nansulate. It is a corrosion protection and a thermal insulating coating.

http://www.nansulate.com/

---best,czes

What about Ceramic Fiber

1. Ceramic Fiber Insulation -Unifrax Durablanket S Ceramic Fiber ...

Ceramic Fiber Paper (Higher Density than Durablanket S)

2. Ceramic Fiber - Mineral Wool Insulation: Refractory Specialties ...

3. Realizing the Benefits of Ceramic Fiber Insulation

4. Ceramic Fiber Insulation

5. Thermal Ceramics

One thing to remember. When putting something inside of a duct, you do not want something that is going to take up a lot of space or create wind resistance. With this in mind, I would suggest the aluminum coated bubble wrap. I have been looking at Prodex to coat the outside of my ducts and water lines. According to the company's website, it has an Rvalue of 14.5 and is very thin. The aluminum foil coating would not create wind resistance within the ducts (causing extra work for the blower). You can request some product samples from these companies that create this type of insulation. It took about 4 days for me to get my samples in the mail.

At Ducts Unlimited we produce flexible, non-metallic ducts for militaries and their defense contractors worldwide. We find that it is the Europeans who request fiberglass inso in their ducts, while Americans are content with polyester and melamine foams. We get it from the company listed below. You should be able to get their spec sheets by emailing Fischetti. Good Luck.

AMERICAN ACOUSTICAL PRODUCTS

311 HOPPING BROOK RD

HOLLISTON, MA 01746

T508 429 1165; T774 233 7000; F508 429 8543

BILL STATTON, GENERAL MANAGER;

B.STATTON@AAPUSA.COM

ANTHONY FISCHETTI, T631 271 4490, SALES;

A.FISCHETTI@AAPUSA.COM

BOB AQUILANO, QC MGR,

WWW.AAPUSA.COM