Ducting Systems and Air Ventilation - Duct Liner Insulation Question (with pics)
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zootjeff
07-10-09, 12:42 AM
Basically to run the 205 inches of 20x8 insulated duct with the insulation on the inside from the do-it-yourself sheetmetal house, it is going to cost me 450 dollars!
If I buy the same 205 inches in 60 inch pre-fab sections it costs me 148 dollars without the insulation.
Basically I really don't want to spend 450 bucks. I'd like to go with route B and spend 100 bucks on some kind of insulation solution. Half of it is in the crawl space above so having it insulated on the inside isn't worth it up there. The base is up against the concrete so I have to have it insulated..
Here are some types of insulation for ducts I have seen. All are different:
Type A: This is what lines my furnace, there are no welded pins. The main part is a dense fiberglass, there is a stiff liner that comes in contact with the air. This seems like the most rigid of the types. It is only glued on and isn't mechanically supported on the edges. If I can figure out what this is, it would be my first choice.
http://www.mpegbox.net/hvac/IMG_6961_1.JPG
Type B:
This is a fiberglass insulation with a reinforced foil liner that come in contact with the air. It lined my cased coil. It appears to only be glued on the inside and held in in place on the corners via mechanical wedging-in-place. This would be my second choice.
http://www.mpegbox.net/hvac/IMG_6965_1.JPG
Type C:
This is the typical furnace liner material that I can by in rolls of 100 feet for 300 dollars, and it is what my fabricator used on my custom sheet metal. It isn't very dense and if it is only glued in place I would worry that it would separate the liner from the fiberglass body. The welded pins are helpful for this reason. Since I can only find it by the 100 foot roll and I can't get away with just gluing it in place, this is my last choice.
http://www.mpegbox.net/hvac/IMG_6963_1.JPG
Then there would be Type D: Ductboard. If I can find it for a decent price locally, I could line the metal duct with the ductboard or just use it as the duct.
If anyone has any ideas of part numbers or the trade names of insulation that I should look for, please help me out!
Thanks,
Jeff
-Jeff
If I buy the same 205 inches in 60 inch pre-fab sections it costs me 148 dollars without the insulation.
Basically I really don't want to spend 450 bucks. I'd like to go with route B and spend 100 bucks on some kind of insulation solution. Half of it is in the crawl space above so having it insulated on the inside isn't worth it up there. The base is up against the concrete so I have to have it insulated..
Here are some types of insulation for ducts I have seen. All are different:
Type A: This is what lines my furnace, there are no welded pins. The main part is a dense fiberglass, there is a stiff liner that comes in contact with the air. This seems like the most rigid of the types. It is only glued on and isn't mechanically supported on the edges. If I can figure out what this is, it would be my first choice.
http://www.mpegbox.net/hvac/IMG_6961_1.JPG
Type B:
This is a fiberglass insulation with a reinforced foil liner that come in contact with the air. It lined my cased coil. It appears to only be glued on the inside and held in in place on the corners via mechanical wedging-in-place. This would be my second choice.
http://www.mpegbox.net/hvac/IMG_6965_1.JPG
Type C:
This is the typical furnace liner material that I can by in rolls of 100 feet for 300 dollars, and it is what my fabricator used on my custom sheet metal. It isn't very dense and if it is only glued in place I would worry that it would separate the liner from the fiberglass body. The welded pins are helpful for this reason. Since I can only find it by the 100 foot roll and I can't get away with just gluing it in place, this is my last choice.
http://www.mpegbox.net/hvac/IMG_6963_1.JPG
Then there would be Type D: Ductboard. If I can find it for a decent price locally, I could line the metal duct with the ductboard or just use it as the duct.
If anyone has any ideas of part numbers or the trade names of insulation that I should look for, please help me out!
Thanks,
Jeff
-Jeff
airman.1994
07-10-09, 03:21 PM
Why not insulate the outside?
zootjeff
07-11-09, 01:16 PM
Why not insulate the outside?
Cause the duct is sized for insulation on the inside, the bottom part by the concrete can't be insulated on the outside because they don't make smaller then 8" duct, and cause it looks better..
I went ahead and spent 130 on the ducts and 195 to have the insulation professionally done.. Man this adds up..
-Jeff
Cause the duct is sized for insulation on the inside, the bottom part by the concrete can't be insulated on the outside because they don't make smaller then 8" duct, and cause it looks better..
I went ahead and spent 130 on the ducts and 195 to have the insulation professionally done.. Man this adds up..
-Jeff
airman.1994
07-11-09, 01:52 PM
Cause the duct is sized for insulation on the inside, the bottom part by the concrete can't be insulated on the outside because they don't make smaller then 8" duct, and cause it looks better..
I went ahead and spent 130 on the ducts and 195 to have the insulation professionally done.. Man this adds up..
-Jeff
Can't make smaller than 8''? What kind of company or you getting this from.
That 1in difference with the insulation on the outside will not hurt you.
I went ahead and spent 130 on the ducts and 195 to have the insulation professionally done.. Man this adds up..
-Jeff
Can't make smaller than 8''? What kind of company or you getting this from.
That 1in difference with the insulation on the outside will not hurt you.
zootjeff
07-11-09, 11:07 PM
I was buying pre-fabbed duct and it comes in 8" by various sizes. I could have gotten custom sized duct, but not for 32 dollars for a 5' 8x20 section. It was more like 20 bucks a foot!
The 8x20 turns into a 6x18 with the 1" liner on the inside. A 12" round is about 113 sq inches 6x18 is 108 square inches. I'm sizing it for ~12" round duct.
I thought about just wrapping the upper part because it is in the crawl space anyway, but the duct wrap costs 150 bucks and I wouldn't use it all. The bottom part I wanted on the inside because 12" of it is up against concrete. I just bit the bullet and with with the professional standard inner liner. It will look better anyway..
I basically paid 132 dollars for 4 sections of 5' 8x20 duct. Then paid 195 dollars to get 205 inches of it lined. So I'm at $330 bucks. If I had the custom duct made the quote was $495 to have it fabricated and lined.
Can't make smaller than 8''? What kind of company or you getting this from.
That 1in difference with the insulation on the outside will not hurt you.
The 8x20 turns into a 6x18 with the 1" liner on the inside. A 12" round is about 113 sq inches 6x18 is 108 square inches. I'm sizing it for ~12" round duct.
I thought about just wrapping the upper part because it is in the crawl space anyway, but the duct wrap costs 150 bucks and I wouldn't use it all. The bottom part I wanted on the inside because 12" of it is up against concrete. I just bit the bullet and with with the professional standard inner liner. It will look better anyway..
I basically paid 132 dollars for 4 sections of 5' 8x20 duct. Then paid 195 dollars to get 205 inches of it lined. So I'm at $330 bucks. If I had the custom duct made the quote was $495 to have it fabricated and lined.
Can't make smaller than 8''? What kind of company or you getting this from.
That 1in difference with the insulation on the outside will not hurt you.