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attic in Hawaii


kfunasaki's Avatar
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09-26-04, 06:07 PM   #1  
kfunasaki
attic in Hawaii

hi, recently purchased an old house in Hawaii that has an attic and a slanted roof. would you recommend installing fiberglass installation under the roof or on the floor of the attic? We have two solar attic fans in the roof and do not plan on using the attic for anything. the attic is about 4 feet high in the very center, and goes out about 15-20 feet on each side. we've gotten advice going both ways.
Mahalo!
kfunasaki

 
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09-26-04, 06:36 PM   #2  
First of all, Tak-offa yo shoose at tha dor, no taken mo-betta ons when yu lev Mahalo

If you on OHAU, as I remember, the average year-rnd temp is 82f.
Insulate on the floor of the attic, using baffles at the eave vents to prevent their becoming blocked.

 
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10-09-04, 07:45 PM   #3  
Hawaii insulation

Read the following:

http://www.state.hi.us/dbedt/ert/rf_...l#anchor345946

Insulation is installed on attic floor. In warm climates such as yours where temps in attics can reach 150 degrees when it is 80 degrees outdoors, you need insulation. And, in warm climates, vapor retarders need to face toward the roof in attics to prevent warm, humid air from entering the home. Fiberglass batts appear to be the way to go.

Cellulose or Fiberglass Insulation R-19 R-30
Cost ($) 720 $880
Savings ($/yr) $450 $480
Payback (yr) 1.6 1.8

For R-19 you will need 5-6 inches of fiberglass batts. A white roof will also save you money. Make sure you have adequate attic ventilation.

 
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12-05-04, 11:31 PM   #4  
kfunasaki
insulation of Hawaii attic

Thanks for the guidance! One question--we have a fairly sizable attic and were wondering if we need to insulate the entire attic for effectiveness. Do we need to put insulation in the areas where we don't really care about the heat--i.e. above the stairwell, bathroom, etc.?

 
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