Roof+Venting


 * **TASK STATUS REPORT** ||
 * **Project Description:** |||||||| To determine the most energy efficient style of roof venting for our area. ||
 * **Project Sponsor:** Habitat for Humanity ||||  || Sponsor Rep: ||   ||
 * **Program Manager:** Rich Wells ||||  || **Ethan Lilly** ||   ||
 * Period covered by the report: |||||| November 15 - November 30 ||
 * **Accomplished This Period:** ||
 * * This site was found discussing in great detail ways to have efficient roof ventilation: [|click here] ||
 * **Planned But Not Accomplished This Period:** ||
 * * I still need to find out what was done in the past ||
 * **Objectives To Next Reporting Period:** ||
 * * I will find out what has been done in the past. ||
 * **Risks/Outstanding Issues/Problems:** ||
 * * I need to make sure that whatever I decided works best is what will be the one that is most cost efficient for the home owner. ||

Roof Ventilation Report

The purpose of this task was to determine which style of roof ventilation was more energy efficient, turbine ventilation or ridge ventilation. The turbine vents, or whirlybird vents, are the circular vents that stick up from roof tops and have the spinning tops. The ridge vents you cant see because they are hidden right below the shingles and run along the peak of the roof. This task is important because it can potentially save the homeowner money in energy savings. This is also important for Habitat for Humanity because it can potentially lower the energy star rating of the homes that they build in the future.

The question that needed to be answered by this report is which type of roof ventilation is more energy efficient, turbine ventilation or ridge ventilation. The turbine vents use the wind that blows across the top of your roof to spin the turbine which prevents bad weather from getting into your attic and it also helps to pull out more air. The ridge vent uses more of the temperature of the air to rise out of the top of the attic and let cooler air come in vents lower on your roof. The ridge vents typically also can have guards in place to prevent bugs and bad weather such as rain or snow from entering your attic and causing water damage. Both of these types have been used for a long time now, but the ridge ventilation system has become the more popular option, not only because it is more appealing than having turbines sticking up all over your roof but because if installed properly, it is much more effective than the roof turbines.

The turbine vents are much cheaper than the ridge vent initially. A high quality turbine vent is roughly $50 and can be installed very easily. A relatively small turbine of about 12 inches in diameter can pump out 347 cubic feet of air per minute with a wind of 5 mph. A 14 inch diameter turbine can pump out 1342 cubic feet of air per minute with winds of 15 mph. This means that a typical attic of size 18000 cubic feet can have the air completely changed in 52 minutes by a single 12 inch diameter turbine with an average wind of 5 mph. That is pretty good for a simple turbine vent, but it relies heavily on wind for performance. The best option is to install a ridge vent with external baffles and an internal weather filter, combined with undereave venting. This provides complete airflow through your attic, letting hot air out of the top along the peak and letting in cool air through the lower vents without having to rely on high wind speeds.

For future houses, it might be a good idea to ask the owner whether they would like to pay more up front to save more in the long run or to pay less up front. The turbines are fairly effective when considering their cost. The average wind speed in this area is roughly 3mph so I would greatly suggest paying the extra upfront to save more money in the long run.

In conclusion, the better option is definitely ridge ventilation, due to the fact that it is independent of weather conditions and is proven to work. While turbines are an efficient way to vent an attic, ridge venting is definitely superior.


 * 1) //Ridge Vents, Peak Performers In Ventilation,// Air Vent Inc. web site: http://www.airvent.com Dec. 15, 2010
 * 2) //Roof Ventilation With Turbine Vents, Attic Ventilation - Ridge and Soffit Vents,// Ask The Builder, web site: http://www.askthebuilder.com, Dec. 15, 2010