8" Round Duct Purchase/Insulating

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Posts: 65
Joined: Tue. Jun. 24, 2008 8:53 pm
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: Hyfire II with hot air jacket
Location: Lehigh Valley

Post Mon. Jul. 28, 2008 9:37 pm

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...

**Fall 2008**Got fill of fuel oil...$4.54/gallon...$850 bill...OUCH!! Bring on the Coal!!
**Winter 2008-09** Burned 1000 gallons less fuel oil for season...Return on Investment for my LL Hyfire II - 1 year!!


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Posts: 1117
Joined: Fri. Feb. 29, 2008 7:09 am
Stove/Furnace Make: Chubby Sr. Old School
Location: Winchendon,Ma

Post Tue. Jul. 29, 2008 8:29 am

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.

http://www.homepower.com <-- Great magazine.

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Joined: Mon. Nov. 14, 2005 8:40 am
Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
Coal Size/Type: Rice
Stove/Furnace Make: Keystoker, LL & CoalTrol
Stove/Furnace Model: 90K, Hyfire I, VF3000 Soon
Location: Cuba, NY

Post Tue. Jul. 29, 2008 12:44 pm

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.
- Dave
Hyfire I & Keystoker 90K heating an 1890 Victorian
- Amsoil Authorized T1 Certified Dealer

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