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Blown in insulation: cellulose, fiberglass or mineral wool ?

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  #1  
Old 03-31-11, 03:15 PM
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Blown in insulation: cellulose, fiberglass or mineral wool ?

What is the safest, please?
 
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  #2  
Old 04-01-11, 08:13 AM
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????

Advice I got from very knowlegable people....Cellulose..... is the one to use.
 
  #3  
Old 04-01-11, 08:19 AM
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Not sure what you mean by 'safest'
 
  #4  
Old 04-01-11, 09:07 AM
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If you are really into the eco friendly green world, recycled blue jean insulation is extremely safe meaning healthy without dangerous chemicals, and is class A fire resistant. If not, cellulose is the preferred favorite of many these days based on performance, cost, and health/fire safety.
 
  #5  
Old 04-01-11, 06:58 PM
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mitch17: Yeah a dumb question. I should have given background that attic cellulose is entering our home thru air gaps in can lights, return air in ceiling, etc. It shows up as dust on furniture, bookcases, cabinets, etc.

After air sealing all the gaps I wanted to add more insulation to the existing 6-8 inches in the attic. Choices given me were the three mentioned, (no blue jeans yet).

Thanks
 
  #6  
Old 04-02-11, 09:06 AM
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There should be no leakage from you can lights if they are the correct ones for use in an attic with insulation. If they are ones designed without the sealed metal box around the housing, perhaps installed after the home was built they are the wrong ones and should be considered a fire hazard as they can overheat the insulation for one thing. There are specific can lights for use in ceilings where there is insulation above. Change them if they are not correct. I am not sure what region your house is in and whether ceiling mounted cold air returns are appropriate. If you are living in a cold part of the country they should be mounted low on the walls to create a natural air convection flow, and vapor barrier anyway should be well sealed around them above the ceiling board.
 
  #7  
Old 04-03-11, 09:11 AM
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Equinox: We had a blower door test done a few days ago. The contractor had a hand-held device (flow meter?) and went around pointing it at everything I mentioned, plus electrical outlet/on-off switch plates, exhaust fans, supply floor registers, etc. and said that about 4200 cfm is coming into the house and that based on our 2178 sq.ft. home, we should have only 2178 cfm coming into the house.

I followed him around and put the back of my fingers on the various locations and could feel a breeze. His plan was to air seal enough to keep insulation from entering the house but yet allow 2178 cfm coming in.

Some can lights are "eyeball" type and without my looking up close, it seems fine attic insulation could escape, drift around to the hallway ceiling air return and come back into the house thru the 11 floor registers.

Also, our main trunk under the house is CertainTeed fiberglass duct board, circa 1993 with flex duct which may have been damaged before we moved here in 2006 with rotating brush duct cleaning. I can see some damage to one floor register flex duct now, about a foot or so down from the floor.

Some brand new metal ducting is in order. When, is the question. If we size and install now, for our 3.5 ton unit....and later on replace our 1993 heat pump with a 3.0 or 4.0 ton (as determined by Manual J and D calcs)... would that be a dumb idea?

Any and all comments would be appreciated. This is our first heat pump. Previously, we had gas furnaces, pellet stoves and wood stoves.
 
  #8  
Old 04-03-11, 10:30 PM
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Just make sure that you have the correct can light housings for use where they are recessed into attic space and covered with insulation. It doesn't sound like they are and when you add more insulation your fire risk will increase if in fact they are not the correct ones.
 
  #9  
Old 04-17-11, 09:02 AM
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Pretty sure we will get complete new ducting under the house. Can anyone comment on how it should be sized? To our existing 3.5 ton unit? Or to what the Manual J and D calcs say?

What if those calcs say I need a 5 ton unit (as one contractor said, after doing Man J and D calcs?

What I am getting at is.......can I run our 3.5 ton unit with the new ducting until it comes time for replacement?
 
  #10  
Old 04-18-11, 12:10 PM
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If you work to the European Passive House level of half an air change per hour, you will save a fortune.
But these are only man made rules based on small European homes.
American homes tend to be a lot bigger than European.
Keeping in mind that you can always open a window or door if you are having a party with lots of people, working to a zero infiltration or the lowest possible seems the best idea, when most of the time the home may only have one or two people in it.
It is air leakage, hot air drawn in that costs.
 
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