# roof vents to cut cooling costs



## sharon (Sep 26, 2005)

Are the vents you can install in your roof really worth it?  I mean do they really make a difference in your cooling costs?  If so, which ones are the best?

sharon


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## Bill (Oct 11, 2005)

YES THEY ARE NECESSARY!!! When it gets hot outside the air comes in from your soffit and rises under your roof sheathing.  This warm air goes out the vents thus your attic space is cooled.  This helps in the winter also by removing water vapor from your attic area.  The condensation will cause your insulation to be compromized.  In very cold area like Minnesota etal where Ice dams are common the venting along with insulation minimize the ice dam.


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## FirTrader (Oct 11, 2005)

It also lets your shingles live about 10 years longer.  Shingles fail much faster if there's no air-space below the sheeting on the roof to provide some cooling.


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## glennjanie (Mar 1, 2006)

I reccommend the use of a continous ridge vent and continous eave vents; its called the "ice house effect" which allows air to move up the decking from bottom to top of the whole roof. A rule of thumb is to calculate the sqrare feet of attic space and use one square inch of ventilation for each square foot of space. Cardinal law!!!! Do not cover vents in the winter time; it causes sweating in the attic--then rotting--and poor insulation. If your home is properly insulated and the roof properly vented yours will be the last in the neighborhood to melt the snow off.


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## mickmar (Mar 2, 2006)

sharon, the more vents you have the better. You want the temperature in your attic the same as the outdoor temperature. The only ones that I would not install are the whirlybird ones you see. They can develop a squeeck and drive you nuts. Talk to a good insulation company, venting is just as important as insulation. Mick


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## MONTY (Aug 28, 2006)

TEXAS A & M DID A STUDY & FOUND THE WHIRLYBIRD VENTS RELEASE ZERO HEAT WHILE MOVING. THERE IS NO WAY FOR THIS DESIGN TO "DRAW" HEAT OUT WHEN TURNING.
ANOTHER OPTION OR TWO IS RADIANT BARRIER PLACED OVER CEILING JOISTS. SEE 

What Is Radiant Barrier Reflective Insulation?
Radiant barrier insulation is a reflective insulation system that offers a permanent way to reduce energy costs. Radiant barrier insulation systems reflect radiant heat energy instead of trying to absorb it. A pure aluminum radiant barrier reflective insulation is unaffected by humidity and will continue to perform at a consistent level no matter how humid it may be. A radiant barrier insulation system is a layer of foil facing an airspace and is installed in the envelope of a building. 

Most people are familiar with traditional insulating materials such as fiberglass, cellulose, Styrofoam, and rock wool. These products use their ability to absorb or resist (slow down) convective and conductive heat transfer to insulate (R-value). A third, seldom discussed but dominant form of heat transfer exists: radiant heat transfer. What are the differences among the three forms of heat transfer? 





 Conductive: Direct contact. If you touch a pot on the stove, this is conductive heat transfer. 

 Convective: Steam, moisture. If you put your hand above a boiling pot, you will feel heat in the form of steam. This is convective heat transfer. 

 Radiant: Electromagnetic. Step outside on a sunny day and feel the suns rays on your face. You are feeling radiant heat transfer. All objects above absolute zero (-459.7 degrees F.) emit infrared rays in a straight line in all directions. 

A radiant barrier reflects radiant heat energy instead of trying to absorb it. What does this mean in your home or business? During the winter, 50-75% of heat loss through the ceiling/roofing system and 65-80% of heat loss through walls is radiant. In the summer, up to 93% of heat gain is radiant. If you are depending on R-value (resistance) alone to insulate against heat gain and loss, remember that thin layers of fiberglass are virtually transparent to radiant energy and are affected by changes in humidity (moisture levels). A 1-1/2% change in the moisture content of fiberglass insulation will result in a 36% decrease in performance (referenced from HVAC Manual 10.6; McGraw-Hill). A pure aluminum radiant barrier is unaffected by humidity and will continue to perform at a consistent level no matter how humid it may be.


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Testing and Approvals 
Building Officials and Code Administrators 
International Conference of Building Officials 
Southern Building Code Congress International 
Metropolitan Dade County (FL) Building Code Compliance Dept. 
United States Testing Company 
Tennessee Valley Authority 
Tennessee Technological University 
State of California 
Oak Ridge National Laboratory 
Texas A & M University 
ALSO SEE:

 NASA Quest > Aerospace Team Online  80% |||||||||||||||||||| 
 ... thermal protection materials. An example of a thermal protection material
is the ceramic tile on the Shuttle Orbiter. It uses heat ...  2002-11-01
 + Highlighted 
http://quest.arc.nasa.gov/people/journals/aero/raiche/arcjets.html - 16k 

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
RADIANT BARRIER
 Technology Transfer Program - At Home with NASA  60% |||||||||||||||||||| 
 ... Their NASA-derived Smart-House Radiant Barrier is designed to reflect away 95 percent
of the sun's radiant energy. Pretty cool! Back to "At Home With NASA".  2005-10-12
 + Highlighted 
http://techtran.msfc.nasa.gov/at_home/home5.htm - 4k 


 AT Technology Transfer Homepage  50% |||||||||||||||||||| 
 ... As her alarm sounds, Amanda awakes refreshed and ready to face her busy day after
sleeping snugly in a home insulated with radiant barrier technology developed ...   + Highlighted 
http://technology.jsc.nasa.gov/space_foundation.cfm - 28k 


 Innovation (Jan/Feb 97) - Insulation  40% |||||||||||||||||||| 
 ... Energy Q Radiant Barrier is the commercial name for the material, manufactured
and marketed by Tech 2000 LLC of Roswell, Georgia. ...  1997-02-01
 + Highlighted 
http://nctn.hq.nasa.gov/innovation/Innovation51/insulatn.htm - 4k 

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OPTION # 2 IS A CERAMIC COATING OVER SHINGLES IN ANY COLOR MATCH.
THIS 
SEE:
http://www.mascoat.com/
INFRARED SURVEY;
[email protected]

THERE'S YOU SOME OPTIONS,
MONTY / [email protected]


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