How to choose the right shape gable or attic vent for a house...
The best questions would be how much vent-able space is available and how much air needs vented? Going off the calculations for net free air is not always perfect. These computer calculations are just that, text book. If the home is a square or rectangle box, venting is easy. A vent on both gables of adequate size for venting with proper cornice vents for intake. And do not fill the attic full of extra boxes. Once the loft is blocked by too many obstacles, the air flow is greatly restricted. The attic is not a storage unit. Too many items in the attic can be a fire hazard. Items that need stored there can be placed safer towards the center of the attic still allowing air to escape from both gable ends.
Homes shaped as a "T" or "L" can be confusing. But do not need to be. Every wall stopping point is where ventilation is needed. These 2 shapes should have 3 exhaust vents. As for sizing, the net free air only calculates the square footage of the attic not the cubic area. Shorter attics retain heat at a noticeable lower lever as a person's head is right in the heat wave. Taller attics have a more welcoming atmosphere as the hotter air rises to the peak. At a standard walking level, this loft may feel cooler, but the heat is still there cooking the shingles from both sides.
As triangle vents are the best for the highest point of ventilation, they are also adjustable on the size opening. If a larger vent is needed, just trim down the bottom of the triangle gable wall opening. A simple rule of thumb to appeal to the aesthetics and exhaust properly, measure up the gable end in the center. The base of the triangle vent should be about 5/8 to 3/4 up the wall for the triangular base. Example: The gable end is 10 foot tall. Then the vent should start around 7 foot up and stop at the overhang. This will render about a 36 inch vent height plus the pitch of the roof for the vent base measure. But there again, every home is different. The only tried and true method of knowing if the home needs more ventilation is to place a thermometer in the attic and monitor the hottest parts of the day. If the attic temp reaches over 130 degrees, more vents may be needed. Over 145 degrees, definitely needs better air flow.
Some think attic vents are only good for summer use. They also assist in the home's health in the winter. During cold weather a gable vent can aid in the expelling of moist air to keep the attic dry. Preventing mold and mildew from taking root. Walking into a damp root cellar or basement, moisture is expected, but not in the attic. When properly vented the space should stay dry and crisp during the cooler months.
Choosing the best shape of your gable vent can sometimes be easy and other times be hard. Is it an existing vent that needs replaced? The old vent will tell you the shape you need. But when dealing with new construction, maybe choose by the appearance of the shape against the wall of the home for a more aesthetically pleasing result.
Triangle gable vents usually mount right up against the cornice at the peak of the gable allowing the best air flow through. The closer the vent is to the top of the attic wall, the more hot air can exhaust quicker. Since hot air rises, the higher up the gable wall, the better for any hot air exhaust vent. With most gables being pointed at the top creating a triangle pitch, triangle vents are ideal when venting this space.
Square and rectangle louvers can be used low in the gable for cool air intake or placed at 3/4 height of the attic wall or higher to exhaust air. Around the half wall height, the square or rectangle vent can intake or exhaust depending on the temperature inside the attic and the temperature outside. This is why vents placed low are intake vents and placed high for exhausting.
Round gable vents are just nice to look at when you have too many straight lines on a home. Most homes seem to be built on square boxes with triangles on top. The curvature of a round vent can break up the monotony and add comfort to the style of the home.
Octagon vents can bring alignment to the boxy and triangular lines forming the silhouette of a building. Since the octagon has straight lines horizontal and vertical, also diagonal lines on both sides, it encompasses the lines of a square and triangle mixed together.
Half Round louvered vents allow for a straight line bottom as a starting point. But the real beauty is in the curvature of the arched top with a smooth face. Bringing the house design together at first but topping it off with a twist.
Tombstone gable louvers appear just like a half round with a fuller box body for areas of the gable that may need more ventilation or even more of a wall break up. Having a beautiful home without the right accessories can leave the home looking plain like every other house on the street.
Cathedral gable vents can emulate the entire wall and gable shape. With a boxed body and a triangle vent style on top, it can be placed 3/4 up the wall or above as high as the peak of the gable wall.
Left and Right Triangle louver vents are great for wing walls and chimney wall stops. Where a triangle vent would be ideal but one half of the vent is missing or cut off.
What about other gable vent and attic louvers shapes? Yes. We can custom make any shape vent you want and need. Just send your design to [email protected]