8" Round Duct Purchase/Insulating

Planning the hot air ducting from my Hyfire II. I will be running 8" galvanized duct. Home Depot/Lowes have it for arond $10 per 5'. Anywhere else have better pricing?

What product do you use to insulate the duct work? Sleeves, sheets, costs? How to install it?

I really do not want to use flex duct. I am a Realtor and I have seen too many examples of professionally installed flex duct shoved into openings/kinked/compressed to even try this.

Had this "dumb" idea...depending on the costs of duct insulation would it be cheaper to use the next size up flex duct as the insulation? 10" as a sleeve over the 8" ducting? 25' for $40...

thanks

I don't think $10 for 5' of 8" pipe is a bad price at all. I will be setting ours up in the near future and was looking at insulating the piping to keep all the heat in it and I too did think of using the insulated flex piping to go over the solid metal pipe, just make sure all your seems are sealed with metal tape before you cover it up. They have a insulation wrap that they install around the pipe's, I would also look at that and compare the insulation values to both before deciding on one or the other, heck I may even look at doing both if it would help insure any loss of heat.

I would think that straight pipe would allow for a better air flow then a flex pipe would, just for the aerodynamics sake of it.

I bought a 25' section of the 8" insulated duct, and ripped out the center flex/plastic liner and put it over my galvanized 8" rigid pipe.
or you could wrap it with a foil/foam stuff too.