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The thing that makes roof insulation a good thing is it is a passive method of keeping heat out. Fans are active and require energy use for the life of the structure. And all they do is push heated air around. Our electric rates are very high.
By my calcs if you applied $50 per month toward the principal of your mortgage instead of your electric bill you could pay off a $100,000 mortgage six years earlier. Take a 30 year mortgage and pay it off in 24 years. Which is the better investment for an individual or society? Buying insulation and or buying electricity?
Assume the best and ask questions.
Punaweb moderator
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We had a solar powered fan installed in the roof over our living room over a year ago. It has made a substantial difference in the interior temperature. There is no cost for electicity to operate it. We'll have the roof painted with some kind of reflective coating soon.
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I like the idea of using insulation in the attic space but what if you don't have any space? My kitchen, dining, living area are under an open beam sealing. Painting or coating the roof may not such a good thing to do if you are on a catchment.
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KathyH - Don't seal those holes! Add heavy-duty screen behind them to keep the critters out. This house has the holes, with heavy-duty screens, just not enough holes and not large enough gable vents and no other venting either. There aren't any critters up there - just heat.
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I'm assuming a ridge vent/soffit vent combo is not do-able in Hawaii?
Puna: Our roosters crow first
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Actually, that is one of the options listed in the new building code. The additions and addendum's listed in the code allow for numerous options in order to allow for many building styles.
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Kathy, If you do go the insulation route go with R19 or greater. R19 has 72% more heating/cooling value then R11.
Make sure you install it properly.
Not only will you be cooler and warmer but the sound of hard rain will be dulled much more as well.
http://www.thisoldhouse.com/toh/video/0,...65,00.html
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KathyH,
Rather than more bird holes, remove the entire frieze blocks (the pieces that the bird holes are drilled in), say, every fourth one and replace it with rafter vents or Hardware cloth. You will get a ton more ventilation. More holes will be a marginal improvement.
Dan
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Kathy, the reflective stuff is radiant barrier and is available at Home Depot in 4'x125' rolls for about $60. BY FAR, this will be your best and most effective investment and will cool your house SIGNIFICANTLY. I am a contractor and have been installing them for the past 9 years. There is no better bang for your buck.
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Kathy,
If you have 10 ft. ceilings, then it is inside that needs ventilating. The hot air rises by convection to your ceiling, then heats downward radiantly. Install a couple of operable windows (awning style) at the ceiling level to allow that hot air to escape.
The thermal barier is interesting, but I have never used it. Is it suspended with only staples? tear-proof like tyvek? I have my contractors license in California where we insulate ceilings to R-38. But attic ventilation is still very important.
Dan
