Insulation:
Some Quick Answers to Specific Questions

What is Low e-reflective Foil Insulation?
The foil systems are not insulation.  They do work but with varying effectiveness.  Better roofing material such as solar reflective clad metal, even the “browns” cut heat gain substantially. More information on Radiant barrier systems can be found at: http://www2.fsec.ucf.edu/en/publications/html/FSEC-CR-1231-01/index.htm   Radiant barrier combined with attic floor insulation makes a good system for a vented attic

What about Closed Cell Foam?
Closed cell foam is excellent insulation; nominally R-6 per inch and at this thickness, an excellent vapor barrier.  Additionally it adds some structural strength.  Formally polyurethane foam had problems with allergic reaction to the formaldehyde in it, but this has been removed from most brands.  NO fire protection is the only draw back.

Open celled foam
Open Cell foam is not as good an insulator, does not seal against moisture and adds little structural strength. Generally costs as much as closed cell or more. Little fire protection though it will not support combustion.

Blown fiberglass and mineral wool
Will not burn and is cheap for the amount of insulation (approximately R-3+ per inch).  Major disadvantage – requires 10 inches to get R-30.  This is a problem if you intend to use your attic for storage.

Blown Cellulose
(approximately R-3 per inch) Doesn’t support combustion when new.  The borate used as fire retardant also is an excellent insecticide that is harmless to mammals.  Old installations have had the borate “leach down” from the top layer leaving a shallow layer that may cause fire to spread. This has not been proven.

Blown fiberglass and cellulose
These can be “fluffed” by using too much air pressure when installing so that there is more depth than there should be (or less insulation for a given depth). Both of these perform better with an air barrier like “house wrap” which will let the moisture escape, but prevent air currents from circulating into the top layers of the insulation.

Are there any documents that would guide me with the pros / cons of each type? 
The above comments highlight the basic differences, but R value is a measure of the resistance to heat penetration or in other words how long it will take the heat to pass through a given depth/thickness.  Insulation doesn’t stop heat, just slow it down.  If you slow it down sufficiently, then the source goes away and it starts going back out.  Some of the Florida Energy Center (fsec) papers below will show this graphically.  What we try to do is to keep the heat from getting through the insulation until the attic has cooled down in summer or warmed up in winter.

Any of the above insulations at the same R value will work about the same.  Price is usually the deciding factor with space available next (cathedral ceilings need more help).  If money is no object and you DO NOT have natural gas in the attic, with asphalt shingles I would recommend the urethane foam under the roof as the best system, especially if you plan to use the attic for storage.  The radiant barrier on the underside of the rafters with blown mineral wool would be next.  A high quality, highly reflective metal roof is much better than asphalt shingles no matter how you insulate, but costs about twice as much.  It also lasts more than twice as long.  The only thing better is the white barrel tile, but that is a lot more than twice as much.

Foam vendors say they will close up my attic completely, with no ventilation left open. Is this a good thing here in Louisiana?

If you do not have any natural gas piping in the attic, this is the best way.  5 ˝ inches will give you an R value of 32 which is sufficient for here.  It will keep your attic temperature down so that your air conditioning ducts won’t heat up.  Typical attics can reach 150 degrees.  With adequate roof insulation the temperature should not exceed 100 degrees (90 is more likely).  See this paper for pros and cons: http://securedb.fsec.ucf.edu/pub/pub_show_detail?v_pub_id=4116

Is there is any information or site you can point me to so I can objectively look at the pros and cons as it pertains to the climate here in Louisiana?

The Florida Solar Energy Center (fsec) is an excellent resource.  They do work for DOE and others.  Florida's climate is very similar to Louisiana. http://www.fsec.ucf.edu/en/

"Flexible Roofing Facility: 2002 Summer Test Results" http://securedb.fsec.ucf.edu/pub/pub_show_detail?v_pub_id=3958

"Flexible Roofing Facility: 2001 Summer Test Results" http://securedb.fsec.ucf.edu/pub/pub_show_detail?v_pub_id=3966

"Comparative Evaluation of the Impact of Roofing Systems on Residential Cooling Energy Demand in Florida"
http://securedb.fsec.ucf.edu/pub/pub_show_detail?v_pub_id=4120

If you have more specific questions, we will be happy to answer them. 

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