Ventilation: 5 Myths about Attic & Roof Ventilation

Kozy Services > Energy Efficiency > Ventilation > 5 Myths About Attic Ventilation

Few things are more misunderstood about houses than attic ventilation. In essence, all ventilation is about circulating air to keep it fresh and to reduce moisture levels. The American institute of architects estimates that 90 percent of homes in the United States have unacceptably high levels of moisture. Understanding whether your home could benefit from some form of attic ventilation might just be a life-saver for your homes roof and overall structure. Here are some of the myths and the facts you need to know about attic ventilation.

1. More attic ventilation is good:

Just like properly sizing your furnace and air conditioning unit, you want precisely the right amount of attic ventilation for your home. Insufficient ventilation can lead to moisture problems during the winter and decreased energy efficiency during the summer, but too much ventilation can be just as bad, if not worse. Roof vents create an additional roof penetration-essentially another place of vulnerability where leaks can occur. Some vents are necessary, but you don't want to needlessly increase the number of roof penetrations. Also, to much attic ventilation can cause the conditioned air in your home to be pulled into the attic, causing your air conditioner and furnace to run longer in order to heat and cool your home.

So, how much ventilation should you have? Without exception, you should schedule a free in-home evaluation with us to determine what your home requires. Generally speaking, you need a ratio of 1:300, where for every 300 square feet of ceiling space, you need 1 square foot of attic ventilation. With that said, air resistance and interference (such as vent grates) reduces the area of true ventilation. In other words, the entire vent opening doesn't count as vented space.

2. Attic Vents and Roof Vents are for Warmer Climates only:

Too many people believe the importance of roof ventilation is to increase energy efficiency during the summer. Good roof ventilation can do this, but roof color, sun exposure, and attic insulation are exponentially more important to overall energy efficiency than roof ventilation. So installing roof vents on your home can reduce your cooling load during the summer, and help remove moisture in the winter. Meanwhile, preventing moisture damage is a much greater benefit and applies to winter more than summer.

3. Roof Vents remove warm air from my home during the winter:

Too many people believe that because heat rises, ventilating an attic space during the winter means you're releasing warm air and creating a drag on your heating efficiency. If this is true, you've got bigger problems to worry about than letting warm air escape from your home. Poor insulation is usually the culprit, although if you enter the attic on sunny, winter day, your attic space can be warmed by the sun more than your furnace.

Unless your roofing system has insulation on the roofing deck and is designed without ventilation, your furnace should not be heating your attic. Worse yet, inadequate insulation is almost surely allowing moisture-laden air into your attic. When this warm, moist air hits your roof, it's likely to form condensation that will lead to further deterioration of your insulation and/or wood rot. If you think this might be a concern, wait till the sun goes down and measure the temperature in your attic. It should be pretty close to the outdoor temperature.

4. Research Studies:

Numerous studies (from the Building Research Council, the U.S. Department of Energy, and the American Society of Heating, Refrigeration and Air-Conditioning Engineers, among countless others from roofing manufacturers) have been completed regarding the effectiveness and optimization of general roof ventilation and particular types of roof vents. The benefit of roof ventilation is undisputed; the best kinds of roof vents are a lot trickier. Laboratory settings are a poor indicator of real world wind and weather behaviors. Moreover, regional differences magnify certain traits of roof ventilation over time. What works best in Dallas, TX is probably not the same as what works best in Cleveland, OH. In some ways, roof ventilation is as much as an art as it is a science, and installing your own roof vents based on something you read online is like trying to diagnose a skin rash using WebMD.

So let the attic ventilation experts at Kozy Services determine the proper attic ventilation for your home,and then you can be assured that your attic is removing heat in the summer and moisture in the winter.

5. I have some attic vents on my roof, so I have good attic ventilation:

While hardly anybody agrees on the best roof ventilation system, everybody agrees some roof vents do hardly any good at all. Take, for example, ridge vents. The majority of roofing experts agree that ridge vents are the most effective and cost-effective roof vents available. Without proper baffles, blinders that prevent outside air from crossing over the vent, a ridge vent may create almost no ventilation at all, as the outside air crosses over the ridge vent it can keep air trapped inside your attic. Gable vents may circulate air through only a small percentage of your attic. Static and roof-line vents are effective for ventilation, but generally aren't recommended due to issues with leaks. Using only Soffit vents may leave air trapped at the top of your attic.Our team of attic ventilation experts has determined through trial and error, along with customer feedback, that the best attic ventilation system for homes located in the Dallas, TX area is with a combination of solar roof ventilators and soffit vents.

If you don't know how your roof vents work, or if you're unsure about your attic ventilation in general, you should call Kozy Services to talk with us about your attic ventilation system and any inherent weaknesses that may be at work.

The risk/reward for having no attic ventilation or poor attic ventilation, along with the negligible cost of installing a good-working attic ventilation system makes attic ventilation one of the most unforgivable sins of home maintenance negligence.

Call us today at (972) 276-2544 for a free inspection of your attic ventilation fans and soffit vents.