Area Calculator
One of the more frequent questions we receive from roofing professionals and homeowners is, “wow many vents do I need for my attic?” Determining the number of vents needed to properly ventilate an attic is not complicated if you have handy tools to help. AirVent®’s Net Free Area Calculator is one such tool.
“We designed the calculator to literally allow someone to input the attic’s square footage and it will start offering options right away. There’s no buttons to press. It’s instantaneous,” said Justin Ache, AirVent/Gibraltar’s Marketing Specialist who created the calculator. “The calculator shows every intake vent and exhaust option we have.” The lineup of products listed inside the calculator includes ridge vents, wind turbines, box vents, fans, and an assortment of intake vents.
One of AirVent’s longstanding messages to the industry is to balance the attic airflow with equal intake and exhaust. This gives the attic airflow the best chance to fight heat buildup, moisture buildup, and ice dams. The Net Free Area Calculator has built this into its logic.
“It’s very important to remember that what goes out must come from somewhere,” Ache explains. “If you do not allow for intake it’s going to come from some other part of your roof, including from other attic exhaust vents, which is not desirable. The Net Free Area Calculator specifically calls out the Net Free Area required. So anyone using the Calculator just has to make sure the Net Free Area of exhaust is matched by the Net Free Area of intake. That number is very clear and plain as day.”
Anyone who does not know the attic’s square footage could start using the Net Free Area Calculator by inserting an approximate attic square footage. You could circle back down the road after you have time to actually measure the attic. Another way to obtain the attic’s size is to refer to aerial views of the house that shows the footprint dimensions.
Many people ask if the steepness of the roof or the amount of volume in the attic affects the math or affects the number of vents needed. It does and the Net Free Area Calculator accounts for this. “Think of a shoe box. Everyone can picture a shoe box and its length, width and let’s say it has a height of six inches,” Ache said. “But if you had a very tall box, let’s say a boot box, it’s the same width and length but much taller than a shoe box. It’s easy to then picture why the tall boot box has more volume than the smaller shoe box. So tall pitched roofs is the same concept. There’s more volume in a steeper, taller attic. Our Calculator takes that into consideration and offers the correct amount of anticipated intake and exhaust vents per the pitch of the roof.”
Keeping the user in mind, the Net Free Area Calculator is mobile friendly. “We designed it to first work on mobile devices,” Ache says. “You can set up a bookmark or a shortcut directly on your phone for fast access for both IOS and Android devices.” Ache encourages the industry to please send feedback about the usefulness of the Net Free Area Calculator and any suggestions for enhancements. You can find the Net Free Area Calculator at www.gibraltarbuildingproducts.com. You’ll also find a soffit calculator and several metal roofing coil calculators.
www.gibraltarbuildingproducts.com
