RoofViews

Residential Roofing

Power Attic Ventilation Options for Residential Projects

By Dawn Killough

December 20, 2021

Power attic ventilation options

A balanced attic ventilation system helps reduce damaging heat and moisture in attic spaces, which may help reduce the load on air conditioning systems and lower the risk of ice dam formation in the winter.

Here are some of the most common attic ventilation systems and how to determine which option may be right for you.

Power Attic Ventilation Systems

Under the umbrella of powered attic ventilation systems, you have a few options to consider. Powered vents come in solar-powered and hardwired versions, and they can be roof mounted or gable mounted. In order to stay efficient, most systems use a thermostat to trigger power attic fan operation—but it's worth digging a little deeper into how these systems differ.

Hardwired Powered Vents

Hardwired powered vents are connected directly to the house's electrical system, providing a consistent source of power. Fans come in a range of power levels depending on the level of air movement needed. For example, the GAF Master Flow ERV6 Roof Mount Power Attic Vent provides 1,500 CFM for attics up to 2,800 square feet.

Solar-Powered Vent Fans

Solar-powered fans are easy to install. They rely on a small solar panel for power, making these vent fans a great option in areas with good exposure to the sun. Some solar-powered fans come with batteries or the option to connect to the building's electrical system as an alternative to solar. This helps to ensure that the fan has consistent access to power. GAF has a high-powered model in its Master Flow line as well as unique dual-powered models that switch automatically between solar and house power.

Roof Mounted Power Vents

Power vents can be mounted on the roof surface, generally close to the ridge or to the highest part of the attic. Most roof vent fans have a low profile, but customers may want to have them installed on the back of the roof for aesthetic purposes. The GAF Master Flow ERV4 Roof Mount Power Attic Vent provides enough airflow for attics up to 1,600 sq. ft.

Gable Mounted Powered Vents

Gable mounted vents are installed on the side wall of the attic. They come in both hardwired and solar options. Installed on the interior of the attic and with no exterior profile, the fans are easy to hide; the GAF Master Flow EGV5 Gable Mount Power Attic Vent is also an easy power vent to install.

Is It Best to Use Electric or Solar-Powered Attic Vents?

Electric hardwired attic vents are a good option when there is limited exposure to the sun and for higher-powered fans. Hardwiring provides a consistent power source that doesn't depend on natural conditions.

Solar-powered attic vents are a good option when exposure to the sun is not an issue and your project doesn't require a higher-powered fan. Overall, solar power vents often work best in climates which have less excessive heat. Regardless of what option you select, it's critical to ensure that the system is balanced.

How Much Does It Cost to Install a Power Vent?

Installation costs vary depending on the amount of work required and the number of fans needed. Some common costs include:

  • Powered ventilator (cost may vary depending on the size and type)
  • Penetrating the roof or side wall of house, if not already done (costs may vary)
  • Installation labor (costs may vary)
  • Wiring from vent location to the nearest electrical source (costs may vary)
  • Making electrical connections (costs may vary)
  • Exterior louver if gable mounted

Other Options for Attic Ventilation

Other popular options for attic ventilation include static and mechanical vents. Static vents are openings that allow hot air to escape as air flows through the attic: air comes in from the intake vents at the lower level of the roof and rises to the top, where it exits through vents on the ridge or roof high point.

Mechanical vents rely on wind power to turn a turbine, which draws hot air from the attic to the outside. These fans rely on a fairly constant wind of at least 5 miles per hour to keep the air moving.

If you'd like more information about power attic ventilation design and options, visit the GAF Learning Portal. For attic ventilation products that keep your most critical needs in mind, consider the GAF Master Flow product line.

About the Author

Dawn Killough is a freelance writer in the construction, finance, and accounting fields. She is the author of an ebook about green building and writes for construction tech and green building websites. She lives in Salem, Oregon with her husband and four cats.

Related Articles

Contractor installing a residential roof
Residential Roofing

When Is the Best Time to Replace a Roof?

If every day was sunny, mild, and a pleasant 75 degrees, there'd be little reason to wonder about the best time to replace a roof. Of course, not everyone lives in areas with ideal weather conditions, as climates vary greatly across the country.So if a client ever asks, "When is the best time to replace a roof?" your answer will likely vary based on where they live and what each season is like. However, you can share some general pointers in response. Here's what to consider for each season to help answer the question, "when is the best time to replace a roof?"SpringSpringtime is traditionally recognized as the kickoff of roofing season, as outside temperatures begin to warm and activity increases. Thanks to melting ice and snow, it's also the time of year that homeowners may want to have their roofs checked out for damage.While spring offers outdoor temperatures that are more friendly for workers, the season also typically comes with an increased chance of severe thunderstorms (and potentially tornados, depending on the region). Spring is usually a good time to schedule a roof replacement if you just monitor the weather forecast for major events to help reduce the chance of delays.SummerWith spring showers in the rearview, most areas of the country see longer stretches of nice weather during summertime, which lends itself well to working outside. Accordingly, summer tends to be the most ideal time for installing a new roof.But with potentially hot days, when is the best time to replace a roof in the summer? Workers will need to start as early in the day as possible because temperatures are usually cooler in the morning. Depending on the forecast temperatures, the job may need to be spread over a few days, so most of the work can be done in the morning hours before it gets too hot. It's also wise to remind customers that workers will need to have breaks in the shade and access to water to stay hydrated.FallThe autumn months can be an equally good time for a roof replacement as summer, as the hot and hazy days have passed, and severe weather isn't as common. The only exception to this is if you're working in an area prone to hurricanes. Hurricane season runs through the end of November and can cause project delays.In addition to the favorable weather, fall is a popular season for roof replacement because many property owners want to fortify their homes and buildings with a new roof before the winter months.WinterIn some areas of the country, it may be possible to continue roofing installations year-round, including during the winter. In southern regions, for example, roofing replacements can often be completed in the winter, as there's less chance of inclement weather. Temperatures may drop, but not as drastically as in areas that see ice and snow more regularly. Of course, it's still important to reference the relevant local forecast when scheduling upcoming work.Sustained stretches of very cold weather does not constitute suitable weather for the installation of asphalt shingles. All self-sealing shingles must be exposed to warm, sunny conditions for several days before they completely seal. Before sealing occurs, shingles are vulnerable to blow-offs and wind damage. Shingles installed in fall or winter may not seal until the following spring. Shingles that are not exposed to direct sunlight, adequate surface temperatures, or that are not fastened or installed properly may never seal. Failures to seal, blow-offs, and wind damage under these circumstances result from the nature of self-sealing shingles, and are not covered under most manufacturer's warranties. Be sure to follow the manufacturer's instructions for proper installation. While most provide guidance about cold weather installations, it will ultimately be up to you to exercise discretion about when to move forward with an installation vs. postponing the work until more favorable weather conditions are present.Other Factors That May Affect Project TimingWhile weather is likely the leading factor that can disrupt scheduled roofing work, if you want to best answer your client's question of "when is the best time to replace a roof?" you'll need to take other factors into account when setting timeline expectations for property owners. One such consideration is the lead time needed for materials. If your customer chooses an uncommon color or a specialty product, it may take longer for materials to arrive.Another factor to weigh is your own backlog. If your production calendar is booked weeks out, clearly communicate the timing to your customers with the knowledge that weather events could impact the schedule. Regularly communicating with customers and setting accurate expectations are key to a positive experience.Looking to learn more roofing best practices and further expand your knowledge base? Check out GAF's CARE Contractor Training Center to help build your skill set and receive valuable training.

By Authors Karen L Edwards

February 12, 2024

Contractor carrying a box of GAF Cobra Rigid Vent 3
Your Home

Why Proper Attic and Roof Ventilation Matter to Your Home

You may not automatically consider attic and roof ventilation when replacing your home's roofing system. However, it's a key part of the process. Here's why roof ventilation matters and the role proper attic ventilation can play in your roofing system. The Importance of Proper Attic Ventilation Your home generates moisture every day: cooking, showering, and even normal breathing all create moisture that can find its way up to your attic. Without proper attic ventilation, that moisture has nowhere to go. Once trapped, it can damage your interior spaces and reduce the effectiveness of your attic insulation. It can even contribute to the overall deterioration of your roof system and structural supports over time. Ventilating your attic space allows that interior moisture, along with hot air, to be exhausted near the top of the roof through ridge vents, roof louvers, powered vents, or other exhaust vents. Fresh air can also enter the attic along the soffits and eaves. This is referred to as intake ventilation. In order for that moisture and heat to escape through the exhaust vents, fresh, cooler air must be allowed to enter the lowest portion of the attic, at or near the soffits or overhangs. The key to effectively ventilating your attic lies not only in ensuring you have enough attic ventilation for your particular home, but finding the proper balance of intake versus exhaust ventilation. The U.S. Housing Authority recommends a minimum of at least 1 square foot of attic ventilation, evenly split between intake and exhaust, for every 300 square feet of attic floor space. This involves a bit of math, so the experts at GAF have developed a simple-to-use ventilation calculator tool to help you figure out the proper amount of ventilation. Be sure to consult your local building codes for attic ventilation requirements or ask your roofing contractor. Benefits of Proper Attic Ventilation Though they may vary depending on your area and the season, there are some significant benefits to having a well-ventilated attic. Helps lower attic temperature. Proper attic ventilation supports a strong roof system. A balanced and effective attic ventilation system helps exhaust superheated air from the attic, which could save your air-conditioning system from having to work as hard in the summer. Reduces the risk of ice dams. In colder climates, proper ventilation can help prevent ice damming. Allowing cold winter air to pass through the attic keeps your roof's temperature cooler, and helps prevent the cycle of snow melting and refreezing that can cause damaging ice dams. Helps protect your roof system. Heat and moisture buildup can add stress to the shingles and other parts of your roof system, potentially causing premature deterioration. A balanced* and effective attic ventilation system allows cooler, fresh air to enter the attic, forcing out superheated air, which helps protect your roofing system. What to Ask Your Roofing Contractor Most contractors today are installing some type of attic ventilation, but in some cases, they may not be installing the proper amount for the job or they may only be installing exhaust vents, such as a ridge vent. In other cases, they may simply not be installing enough to meet the necessary balance between the two—intake and exhaust. There isn't one universal solution, as every home is designed and built differently. Here are some questions to ask your contractor about your roof ventilation. Based on the size of my attic space, do I currently have enough ventilation? Do I have both exhaust ventilation at or near the ridge of my roof, and intake ventilation at or near the overhang/soffit area? Is there enough ridgeline on my roof to install the right amount of exhaust ventilation? If not, what other types of exhaust vents do you recommend (i.e., power vents or roof louvers) to provide the needed amount of exhaust ventilation? Are my existing overhang/soffit vents clogged by paint or covered with attic insulation? If I don't have any intake ventilation or enough ventilation at my overhang/soffit area, can it be added? Would you mind looking at my attic insulation? Is it in good condition, and does it properly cover the entire attic floor? If you're in need of roof repairs or replacement, reach out to a contractor certified by GAF ** in your area. Be sure to ask about proper ventilation and the options available to ensure that your roofing system will deliver the best performance and protection for your home. *Always have a balanced attic ventilation system. In no case should the amount of exhaust ventilation at or near the ridge exceed the amount of intake ventilation at or near the soffit. See www.gaf.com/ventcalcalculator for details. **Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program and offering GAF enhanced warranties, which require the use of a minimum amount of GAF products.

By Authors Karen L Edwards

January 25, 2024

Roof intake vent
Residential Roofing

5 Common Installation Mistakes When Venting Attics

Roof vents form the base of a home's attic ventilation system, helping it breathe while preventing roof system damage year-round. That's why it's important to understand how the various components work together to create a balanced, effective attic ventilation system. Here are five of the most common ventilation installation mistakes—as well as how to avoid them. 1. Placing Intake Vents Too High or Exhaust Vents Too Low A balanced attic ventilation system draws in fresh, cool air at the lowest part of the attic space and exhausts warm, moist air at the highest point. If either of these vents are placed incorrectly, they reduce the entire attic space's exposure to continuous air flow, reducing the overall system's effectiveness. If an exhaust vent is placed too low on the roof, or if two exhaust vents are stacked, one of the vents might then act as intake and disrupt—or short-circuit—the airflow through the entire attic space, reducing how effective it can be. Make sure that the intake vent is placed at the lowest possible point of the roof (usually at or near the soffits) so that it lines up with the lowest part of the attic space. Exhaust vents should always be placed at the highest possible point on the roof (at or near the ridge) which typically aligns with the highest part of the attic space. 2. Mixing Exhaust Products within the Same Attic Space Installing two or more different types of exhaust vents within the same attic space can also short-circuit proper airflow. When this happens, some of the exhaust vents may act as intake vents, restricting airflow to only the part of the attic space underneath those exhaust vents. Mixing exhaust products could also allow weather or debris to infiltrate the home. If the wrong type of vent for a specific roof design is installed, that can lead to mixing products. When a ridge vent is installed on a hip roof with very little ridge line, for example, it may not provide enough exhaust for the attic space. When this happens, another exhaust fan such as a roof louver or a power vent will be added to boost the ridge vent. However, doing this can lead to problems. A best practice is to install one type of exhaust vent on the attic space that is able to meet the exhaust NFVA (net free ventilating area) requirements, allowing the air to flow continuously throughout that attic space. 3. Cutting the Ridge Vent Opening Too Long Sometimes, a ridge vent might be installed across the entire ridge because it looks good, but there's no need to cut open the entire ridge air slot below the vent. Cutting an opening that's too long could lead to too much exhaust, disrupting the balance of the entire ventilation system. Check that the opening of the ridge air slot matches the amount of exhaust NFVA required for a specific attic space. For example, if an attic space requires 288 square inches of exhaust and you're using a 4-foot plastic ridge vent with 18 sq. in. per lineal foot of NFVA, then only 16 ft. of the 40-ft. ridge should be cut open. Always open the ridge air slot according to the required exhaust NFVA for the attic space, and then balance that with the same amount of intake NFVA. 4. Clogged or Blocked Intake Vents Even when intake vents were correctly installed, they may become ineffective over time if the outside portion becomes clogged with paint, dirt, dust, or even spiderwebs. Vents may also get blocked from the inside if the attic insulation is installed over the vents. Keep the intake vents clean by removing any debris that may have accumulated over time. If necessary, use attic baffles to keep insulation away from the intake vents. Don't forget to check that a hole has been properly cut in the soffits to allow air to enter the intake vents. 5. Having Missing or Inadequate Intake Intake is arguably the most important part of an attic ventilation system. When there is inadequate intake—or none at all—an exhaust vent may not function properly. Static exhaust vents like ridge vents or roof louvers hinge on adequate intake, but the same also goes for powered exhaust vents, which will have to work too hard to pull air through the attic space, resulting in the premature failure of the power vent's motor. Always check that you have a balanced attic ventilation system with the proper amount of intake and exhaust ventilation for the attic space being ventilated. For more information and tools to calculate the amount of ventilation products needed for your attic roof vents, visit gaf.com/ventcalculator.

By Authors Wendy Helfenbaum

January 25, 2024

Don't miss another GAF RoofViews post!

Subscribe now