Air Vent University
Air Vent is committed to helping roofing professionals everywhere by collecting and sharing best practices and solutions in residential attic ventilation.
Air Vent University is an extension of this commitment. Here you’ll find useful information to help you in the field now and as a reference for the future. We’ll add new “lesson plans” regularly. We’ll also mix in some fun with pop quizzes and occasional prizes. And check out our podcast, too. Welcome.
Use the Tabs below to switch between lesson plans and quizzes:
Lesson Plans
Edge Vent Passes 30-Day Ice Dam Test Installing a roof-top intake vent at the edge of the roof for houses in climates battered with snow and ice may cause you to wonder: What happens if an ice dam occurs? This test answers the question. Fact or Fiction? Mixing Exhaust Vent Types is Problematic Never mind what the Installation Instructions, what the shingle manufacturers, and what building code say. Forget all of that. What do roofing professionals across North America say they have witnessed when the project they are working on has pre-existing mixed types of attic exhaust vents on the roof? How Does Proper Attic Ventilation Protect My Roof? (ARMA Video) Every home has a roof, but is every roof properly ventilated to help prevent roof deterioration or roofing system failure? In this short video the year-round benefits of attic ventilation are highlighted so roofing professionals can better understand them and easily share them with homeowners. Video courtesy of Asphalt Roofing Manufacturers Association (ARMA) Lean on Air Vent to Help Educate the Homeowner A roofing contractor interviews Air Vent “Ask the Expert” seminar host Paul Scelsi in two quick minutes to boil down the “How’s and Why’s” every homeowner should factor in when it’s time for a new roof. NOTE: If you’d like your own customized short video with Paul, send us an email and perhaps we can arrange it via a Microsoft Teams video chat (pscelsi@gibraltar1.com). Video interview courtesy of Drew Cope, Cope Construction & Renovation, Kelton, PA. SLA Slant-Back Box Vent Installation Animation In this short video, you’ll see how our metal, slant-back box vent (also called a roof louver or static vent) installs, including positioning on the roof, hole size and using sealant. Hope you find it helpful. Sizing NON-MOTORIZED Attic Vents for the Attic To help you determine how many NON-MOTORIZED attic exhaust vents are needed for an attic (as well as the intake vents required for those exhaust vents to perform properly), Air Vent has three different tools you can use.
1. Use the Air Vent App for iOS and Android devices. It’s free, easy to use and has many additional features beyond a built-in calculator.
2. Use the Air Vent Online Calculator in either its web-based version or the jazzed up spreadsheet that is customizable with your company colors and personalized text message to clients. It’s free as well.
3. Calculate it yourself by hand. You never know when a client may ask you, “Can you walk me through the math used to calculate that?”
• Step One: Determine the attic square footage (measured length x width, floor of the attic). If you cannot measure the attic floor, an acceptable Plan B measurement is the footprint of the house aerial view.
• Step Two: Determine the Net Free Area (NFA) needed in total for the entire attic. (Note: Non-motorized vents are specified in terms of Net Free Area – the clear, unobstructed area a vent has through which air can move.) To do that, divide the attic square footage by 150 (This is based on the 1/150 ratio of attic ventilation; which is 1 square foot of NFA for every 150 square feet of attic floor space. If you want to use the 1/300 ratio, divide attic square footage by 300.) The resulting number is the total amount of NFA in square feet needed for the attic.
• Step Three: Balance the attic ventilation by determining the NFA needed for EXHAUST VENTS and for the INTAKE VENTS. Using the results from Step Two, divide by 2 because proper attic ventilation is balanced between EXHAUST VENTS (which will be installed at or near the peak of the roof) and INTAKE VENTS (which will be installed in the soffit/undereave or low on the roof). The resulting number is the total amount of NFA in square feet needed from the EXHAUST VENTS and the total amount of NFA in square feet needed from the INTAKE VENTS. Next, multiply by 144 (the number of square inches per square foot) because non-motorized vents are specified in square inches not square feet. You now know the NFA needed in square inches for EXHAUST as well as for INTAKE.
• Step Four: Select the EXHAUST and INTAKE Vents Desired and Determine the Quantity. It’s time to pick both the EXHAUST VENT and the INTAKE VENT suitable for the size and design of the roof/attic. Once that is done, learn the vents’ NFA as rated by the manufacturer. Use that NFA number to determine the quantity by dividing the “NFA Needed” by the actual “NFA the vent provides.”
Here’s an example of the math start to finish.
Step One: (measure the attic) 40 feet length x 50 feet width = 2,000 square foot attic.
Step Two: (determine the NFA needed for the entire attic) 2,000 ÷ 150 = 13.3 square feet of NFA in total needed for the entire attic.
Step Three: (balance the system with EXHAUST and INTAKE vents).
‣ 13.3 square feet of NFA ÷ 2 = 6.7 square feet of EXHAUST ventilation needed as well as 6.7 square feet of INTAKE ventilation needed.
‣ (convert to square inches by multiplying by 144) 6.7 x 144 = 965 square inches of EXHAUST net free area needed, and 965 square inches of INTAKE net free area needed.
Step Four: (select the EXHAUST and INTAKE vents desired; determine quantity).
‣ Select an INTAKE vent desirable for the project, determine its net free area rating in square inches per unit/linear foot.
✓ For example, an 8 x 16 rectangular undereave vent allows 56 square inches of net free area per unit. Thus, 965 ÷ 56 = 17 rectangular undereave vents needed.
‣ Select an EXHAUST vent desirable for the project, determine its net free area rating in square inches per unit/linear foot.
✓ For example, ShingleVent II ridge vent is 18 square inches of NFA per linear foot. Thus, 965 ÷ 18 = 54 linear feet of ridge vent needed.
What Size Power Fan Does the Attic Need? To help you size a roof-mount or gable-mount power attic fan (whether traditional electric or solar powered) for an attic, Air Vent has three different tools you can use.
1. Use the Air Vent App for iOS and Android devices. It’s free, easy to use and has many additional features beyond a built-in calculator.
2. Use the Air Vent Online Calculator in either its web-based version or the jazzed up spreadsheet that is customizable with your company colors and personalized text message to clients. It’s free as well.
3. Calculate it yourself by hand. You never know when a client may ask you, “Can you walk me through the math used to calculate that?”
• Step One: Determine the attic square footage (measured length x width, floor of the attic). If you cannot measure the attic floor, an acceptable Plan B measurement is the footprint of the house aerial view.
• Step Two: Determine the CFM needed from the power attic fan to service the attic. Multiply the attic square footage by a factor of 0.7 (this produces 10-12 air exchanges per hour from the power attic fan). The resulting number is the CFM (Cubic Feet of air moved per Minute) needed from the power attic fan to properly exhaust the attic. Find a power attic fan with the required CFM or close to it. NOTE: It’s OK to have more CFM than needed as long as the fan(s) are given the necessary amount of intake ventilation (at the soffit/eave or low on the roof near its edge). That’s the next step.
• Step Three: Give the power attic fan proper intake ventilation. The amount of intake ventilation a power attic fan needs is based on its CFM. If the attic requires more than one power attic fan, this formula applies to each fan used or installed for the project. Here’s the formula:
‣ CFM of the power attic fan ÷ 300 = Square feet of intake net free area needed.
‣ Since intake vents are rated/specified in square inches (not square feet), it’s necessary to convert from square feet to square inches. That is easily accomplished by multiplying by 144 (the number of square inches per square foot).
‣ Once you know the intake ventilation net free area needed in square inches, find an intake vent best suited for the project, identify its net free area in square inches (each manufacturer should publish that number) and determine how many units/feet of intake vent are needed.
Here’s an example of the math start to finish.
Step One: (measure the attic) 40 feet length x 50 feet width = 2,000 square foot attic.
Step Two: (determine CFM of the fan needed) 2,000 x 0.7 = 1,400 CFM power attic fan needed.
Step Three: (give the power attic fan proper intake ventilation).
‣ 1,400 ÷ 300 = 4.7 square feet of intake ventilation net free area needed.
‣ (convert to square inches by multiplying by 144) 4.7 x 144 = 677 square inches of intake ventilation net free area needed.
‣ Select an intake vent desirable for the project, determine its net free area rating in square inches per unit/linear foot.
‣ For example, an 8" x 16" rectangular undereave vent allows 56 square inches of net free area per unit. Thus, 677 ÷ 56 = 12 rectangular undereave vents needed.
What Good Are Attic Exhaust Vents? They’re Not Without Proper Intake Vents Overlooking intake ventilation is the #1 mistake in residential attic ventilation. ShingleVent II Installation Animation In this quick video you’ll see how our four-foot stick ridge vent ShingleVent II installs, including roof pitch requirements, slot cut and the ever important, often overlooked intake ventilation needs. Hope you find it helpful. Attic Ventilation Educational Video This video is extracted from the annual Air Vent Seminar “Attic Ventilation: Ask the Expert™” held in-person for roofing professionals across North America every 1st quarter. The seminar is an overview of residential attic ventilation best practices, solutions, categories of intake & exhaust vents, and much more. Ask the Expert Seminar: Early Notification To be added to the email list to attend a future in-person seminar, please add your email address below, and we'll notify you when our annual Ask the Expert schedule is announced. Click here for additional information about the “Attic Ventilation: Ask the Expert™” seminars. 
Read the Test Summary: Edge Vent Passes 30-Day Ice Dam Test Highlights
Read the article: Fact or Fiction? Mixing Exhaust Vent Types is Problematic
Read why these roofing contractors work hard to avoid it.
Read the article: What good are Attic Exhaust Vents? They're Not Without Proper Intake Vents
Take the 5-Question Quiz
(Shortened version of the “Ask the Expert” Seminar)
Quizzes
View our December 2020 Lesson Plan: Fact or Fiction? Mixing Exhaust Vent Types is Problematic To test your knowledge about what you learned in the December 2020 Lesson Plan featuring the article: Fact or Fiction? Mixing Exhaust Vent Types is Problematic please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
To test your knowledge about what you learned in the November 2020 Lesson Plan featuring the video: November 2020 Lesson Plan: How Does Proper Attic Ventilation Protect My Roof? please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
To test your knowledge about what you learned in the October 2020 Lesson Plan featuring the “Lean on Air Vent to Help Educate the Homeowner,” please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
View our September 2020 Lesson Plan: SLA Slant-Back Box Vent Installation Animation To test your knowledge about what you learned in the September 2020 Lesson Plan featuring the “SLA Box Vent Installation Animation,” please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
View our August 2020 Lesson Plan: Sizing NON-MOTORIZED Attic Vents for the Attic To test your knowledge about what you learned in the August 2020 Lesson Plan featuring the calculations used for “Sizing NON-MOTORIZED Attic Vents for the Attic,” please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
View our July 2020 Lesson Plan: What Size Power Fan Does the Attic Need? To test your knowledge about what you learned in the July 2020 Lesson Plan featuring the calculations used for “What Size Power Fan does the Attic Need?” please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong.
EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
View our June 2020 Lesson Plan: “What Good are Attic Exhaust Vents? They’re not without Proper Intake Vents,” To test your knowledge about what you learned in the June 2020 Lesson Plan featuring the industry article “What Good are Attic Exhaust Vents? They’re not without Proper Intake Vents,” please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
To test your knowledge about what you learned in the May 2020 Lesson Plan featuring our ShingleVent II Installation Animation, please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
To test your knowledge about what you learned in the April 2020 Lesson Plan featuring our Attic Ventilation Educational video, please take our short 5-question Pop Quiz. Your answers will be “graded” as you go, so you’ll know immediately if you were right or wrong. EXTRA CREDIT: Anytime you take any of our Pop Quizzes (from any month, at any time) your name is automatically entered into the current random drawing for a FREE Air Vent golf shirt (10 shirts per month, every month as long as you register). Regardless if your answers are correct or not, you are eligible to win.
Podcast
Airing it Out with Air Vent is a podcast focusing on residential attic ventilation best practices, tips, and solutions. It is an extension of our popular Attic Ventilation: Ask the Expert in-person seminars held for residential roofing professionals across North America every winter. Listen to episodes below, or find us on your favorite Podcast Network.
Episode 9: Occupants of the house generate between 2 to 4 gallons of water vapor daily by cooking, cleaning, showering, doing laundry, breathing and perspiring. In the winter, this water vapor is attracted to the colder, dryer attic where it can become a problem if it’s not properly ventilated. In this episode of Airing it Out with Air Vent, we examine how to fight wintertime moisture. A special thank you to Jerry Becker roofing consultant with Roof Life of Oregon in Tigard, Oregon for sharing his expertise for this podcast episode! Episode 8: It’s impossible to completely stop Mother Nature and the ice dams that impact roofs. But it is possible to reduce their frequency and severity. In this episode of Airing it Out with Air Vent, we share helpful tips in the battle of ICE DAMS vs. ROOFS. A special thank you to all who contributed to this podcast episode!
Sabrina Johnson
Jake Jacobson
Chuck Power Episode 7: When a homeowner is ready to listen to the roofing contractor or home inspector’s assessment of the attic ventilation system, what exactly will be said? In this episode of Airing it Out with Air Vent, here are five key points every homeowner should be aware of about attic ventilation. A special thank you to Shawn Bellis owner of EPIC Exteriors in Overland Park, Kansas for Episode 6: Not every homeowner agrees with the residential roofing contractor’s assessment of the attic ventilation improvements needed. They want a new roof but not necessarily attic ventilation fixes. Sometimes it’s due to price. Sometimes it’s the homeowner’s refusal to understand the project. In this episode of Airing it Out with Air Vent, we let roofing contractors VENT about homeowners. A special thank you to all who contributed to this podcast episode!
Jeff Heitzenrater
Matt Cooper
Corey Ballweg
Clayton Putman
Greg Pike
Sabrina Johnson
Chris Arrington
Jeff Barnett
Richard Turner
Patrick Readyhough
KDCO Home Improvements - Akron, Ohio
SF5 Construction - Little Elm, Texas
Gulfeagle Supply - Michigan
sharing his expertise for this podcast episode!
Triple Peaks Roofing and Construction - Olmstead Falls, Ohio
Redemption Roofing - Conroe, Texas
Mid-Towne Construction - Cross Plains, Wisconsin
Elite Roofing - Denver, Colorado
Campo Roofing - Twinsburg, Ohio
KDCO Home Improvement - Akron, Ohio
Arrington Roofing - Dallas, Texas
Barnett Roofing & Siding - Canton, Michigan
R. J. Turner Remodeling - Winston Salem, North Carolina
Pond Roofing Company - Fairfax, Virginia
Episode 5: It’s hot in the attic. Getting inside the attic can be tricky. And navigating around is not always easy. But skipping an attic inspection prior to installing a new roof could result in a costly callback – possibly a brand new roof paid for by the roofing contractor. In this episode of Airing it Out with Air Vent, Pond Roofing shares its story.
A special thank you to Patrick Readyhough of Pond Roofing in Fairfax, Virginia for sharing his story for this podcast episode!
Episode 4: Sometimes a homeowner or a roofing contractor or even the HVAC contractor during a house call suggests adding a second type of attic exhaust vent to boost the vents already in place. In this episode of Airing it Out with Air Vent, residential roofing pros share their first-hand stories of why mixing types of attic exhaust vents is a problem to avoid.
A special thank you to all who contributed to this podcast episode!
Ron Gonzalez
Trevor Atwell
Tim Chapin
Roofing Contractor - Aurora, Illinois
Atwell Exterior Services - Greenville, North Carolina
Your Safe and Healthy Home - Akron, Ohio
Paul Vosen
Scott Dennison
Shawn Bellis
Degenhardt Home Improvement - Madison, Wisconsin
Dennison Exterior Solutions & Gutter Topper - Saint Joseph, Michigan
Epic Exteriors - Overland Park, Kansas
Ron Bastian
Sean Toms
Tom Picha
Bastian Roofing - Richfield, Wisconsin
S & K Roofing - Eldersburg, Maryland
Affordable Roofing - Aurora, Illinois
Episode 3: No amount of attic exhaust ventilation can overcome the lack of intake ventilation at the eave/soffit or roof’s lowest edge. In this episode of Airing it Out with Air Vent, residential roofing pros explain why they ensure attic ventilation includes exhaust and intake.
A special thank you to all who contributed to this podcast episode!
Sue McCollum May
Chris Arrington
Jeff Barnett
A Better Way Construction and Roofing - Lincoln, Nebraska
Arrington Roofing - Dallas, Texas
Barnett Roofing & Siding - Canton, Michigan
Clayton Putman
Greg Pike
Sandra Daffer
Elite Roofing - Denver, Colorado
Campo Roofing - Twinsburg, Ohio
Hawaiian Built Roofing - Boise, Idaho
Sean Jegen
Sean Toms
Gorilla Exteriors Contracting - Shawnee, Kansas
S & K Roofing - Eldersburg, Maryland
Episode 2: The most qualified people to offer tips and guidance for avoiding mistakes and callbacks are the very people who have first-hand experience with the issue. In this episode of Airing it Out with Air Vent, we asked residential roofing pros to give us their top attic ventilation tips based on what they have seen in the field.
A special thank you to all who contributed to this podcast episode!
Scott Dennison
Tom Picha
Sabrina Johnson
Shawn Bellis
Sean Toms
Dennison Exterior Solutions - St. Joseph, Michigan
Affordable Roofing - Aurora, Illinois
KDCO Home Improvements - Akron, Ohio
EPIC Exteriors - Overland Park, Kansas
S & K Roofing - Eldersburg, Maryland
Corey Ballweg
Jeff Heitzenrater
Richard Turner
Jake Jacobson
Trevor Atwell
Mid Towne Construction - Cross Plains, Wisconsin
Triple Peaks Roofing & Construction - Olmstead Falls, Ohio
RJ Turner Remodeling - High Point, North Carolina
SF5 Construction - Little Elm, Texas
Atwell Exterior Services - Greenville, North Carolina
Tim Chapin
Ron Bastian
Jerry Becker
Sue May
Paul Vosen
Steve DuCharme
Your Safe and Healthy Home - Akron, Ohio
Bastian Roofing - Richfield, Wisconsin
Roof Life of Oregon - Tigard, Oregon
A Better Way Construction & Roofing - Lincoln, Nebraska
Degenhardt Home Improvement - Madison, Wisconsin
Innovative Builders Roofing & Construction - Edmond, Oklahoma
Episode 1: Most attics have incorrect or insufficient ventilation. Our survey shows it’s 77% of today’s homes. So What? In this episode of Airing it Out with Air Vent, we dive deep into the potential consequences of improperly ventilated attics and explain why it matters.
