The best roof vent systems not only extend the life of your roof, they help lower your home’s energy bills and make your home an overall healthier place to live…
Different types of roof vents are more efficient than others, but each type of vent performs the primary function of removing stale air from the attic (exhaust) or bringing fresh air into your home (suction).
If you really want to take advantage of proper roof ventilation, both supply and exhaust ventilation must be installed. However, in many cases forced ventilation is not possible due to the architecture of the house. In these cases, having only exhaust is better than nothing! But for argument’s sake, we can assume that your roof structure can structurally support both intake and exhaust.
Before we look at each type of vent available on the market in 2020, let’s first look at the two types of vents in general…
Two styles of ventilation
What is ventilation anyway? According to Oxford, ventilation is “the supply of fresh air to a room, building, etc.”
The old (air) is outside and the new (air) is inside. In roofing, as in life, this is a very refreshing and important strategy!
Understanding the natural movement of air helps us understand why both intake and exhaust play a critical role in a roof’s ability to ventilate. And it’s important to know how they work hand in hand before choosing which type of roof ventilation system is best for your home and budget.
The escape; Release the stale air
According to physics professor Christoper Baird of West Texas A&M University, “Heat doesn’t rise, warm air rises. (source) ”For the purposes of ventilation of the attic, this is valuable because it is the warm, moisture-containing air that you want to remove from the attic.
Allowing hot air to stagnate can lead to foul-smelling mold and eventually fungus. As mentioned above, this is one of the key reasons why ventilation is important to the health of your home.
As hot air rises, exhaust vents are usually located at the top of the roof. The most common exhaust vent used for modern roofing systems is the ridge vent. At Roof Hub, we install ridge ventilation on every new roof, unless the style of the house allows it.
Remember: ridge vents and other similar exhaust pipes allow hot, humid, stale air to escape from your home, but that’s only half of any great ventilation strategy!
Consumption; Bring that fresh air
Hot air escaping from your attic is important to the health of your home and the longevity of your roof, but hot air tends to be pretty stubborn! He doesn’t want to leave without being kicked out by force, so we need something that can act as a gatekeeper. Enter: fresher air.
Fresh, cool air (in the form of fresh air) is the other half of a great ventilation strategy. Cooler air enters the attic through intake grilles lower in the roof line than the vents mentioned above. Because cooler air enters below the hot air (and because hot air rises), fresh air will help vent the remaining hot air out of the attic. Fresh air through vents (such as a soffit) acts as our lintel.
As long as you have vents with a large enough surface area, this cooler intake air will help push hot air out of the house. In an ideal world, everything is a complete cycle…
Cold air enters through the intake grilles and hot air exits through the exhaust!
What if my roof does not have sufficient ventilation?
The rapid destruction of your home, property and everything that is dear to you. Everything you care about will perish in the most devastating way imaginable. This is a joke.
While destruction may not eventually happen if you don’t have proper ventilation, there are serious deficiencies that will affect your attic space, your roof, your home, and your lifestyle. They include:
• Poor indoor air quality due to dead air in the attic (summer)
• Overloaded HVAC (air conditioning) systems are forced to work harder to cool the second (and third, if applicable) floors of your home.
• Additional humidity (in the form of warm air) in the attic
• Ice dams during the winter months if you live in a colder climate
Important: When used in combination with air intake vents located below the roof line (such as a ceiling vent), the ridge vent offers the best possible vertical ventilation.
Vertical ventilation uses gravity and the natural flow of hot and cold air. Cold air rises from below and exits at the top. This strategy is vastly superior to horizontal or cross ventilation, which we will discuss later.
Almost all roofing companies are familiar with the installation of ridge vents. The installation process involves using a hacksaw to cut a 2″ gap across the entire length of the canopy. After the hole is cut out, the flexible ridge is bent and nailed on top.
After the ridge outlet is nailed over the freshly cut space along the ridge line, the ridge shingle is folded over the outlet and nailed. This special type of shingle is stronger and more flexible than regular bituminous shingles and comes in colors that are perfect for your new roof!
Most modern ridge vents, like GAF’s Snow Country Cobra Ridge Vent, are so strong you can stand on them! Its durability provides additional snow protection in the Northeast and other snow regions of the United States. The way the vents are built into the product usually keeps snow and ice from accumulating that would otherwise block the exhaust of other styles of vents.
The design of the ridge deflector, its location on the roofline, the area covered, and the cost and similarity are just some of the many reasons why this is one of the most popular ridge deflectors. I highly recommend if it suits the architecture of your home.
Ventilation holes on the outside of the ridge
A metal hatch outside the ridge, mounted on a roof made of bituminous tiles with three ledges. This particular vent is the UV-45 Universal Vent available from Active Ventilation Products, Inc (discussed at the end of this section).
Although its name sounds similar, off-ridge venting is similar to ridge venting only because they are both located at the top of your roof. In fact, “exhaust vents” look much more like rectangular vents than ribbed vents.
In general, off-ridge vents are not very popular and we do not recommend them over other more efficient roof vents. Off-ridge vents are not as effective as full-ridge vents because they are much smaller and not located as high on the roof. Their size prevents them from blowing out much hot air, and their location limits their ability to blow out hotter air like a ridge vent.
The most popular vents on the market are about 4 feet long. Often made from galvanized steel, installation involves cutting a vent-sized hole in the roof about a foot below the ridge line.
Ventilation holes outside the ridge are beneficial when the actual roof ridge line is small. This can happen with complex roofs and homes that don’t have a long, continuous ridge line for the traditional ridge vent to pass through. Adding one or two off-ridge vents to these types of roofs can provide additional ventilation in areas that are not getting enough air.
If your home has a lot of peaks, troughs, and dormers, then this could be the type of vent you can incorporate into your ventilation system. However, this won’t always be the case, so be sure to talk to a reputable roofer before calling.
where to buy air vents online
As a roofing contractor, Roof Hub is not the place to buy any attic ventilation devices. Home Depot and Lowes offer a wide selection of common types of roof vents, but we recommend browsing the Roofvents.com store if you’re looking for something more specific. They have roof vents, roof vents and many more options that come in different sizes. If you need it, they seem to have it! While we haven’t used this seller ourselves, they seem to have great reviews and detailed product information.
Ventilation boxes (also known as ventilation grilles)
Box vents are similar to vents outside the ridge.
For these reasons, it’s best to use more natural and tried-and-true stretching methods for your roof. If you already have adequate ventilation in the attic, you’d be better off not adding an electric fan, even if it’s powered by solar panels.
Rooftop turbines (also known as Whirlybird ventilation)
Whirlybird is a funny word and we consider it a significant benefit of having a turbine on the roof. You can stand in your driveway, point to your house, and exclaim to your neighbors, “You see, this is my whirlwind.” Wind turbines are not just about play and entertainment, however there are significant trade-offs that can affect the health of your roof and the ventilation of your attic.
Whirlybird vents were invented in the early 1900s by British inventor Samuel Ewart. The device consisted of aluminum vanes inside an aluminum “shroud” or lid that rotated in the wind outside the house to then draw air from inside the attic and out of the house. Ewart’s original design matches modern tourbillon models.
Rooftop turbines need at least 5-6 mph wind to power and spin the inside blades, meaning they won’t be efficient on days with or without light breeze. If it’s just a form of exhaust on your roof, you’ll be in trouble on hot windless summer days.
Even on very windy days, the power of vortices as a ventilation tool is questionable. They are often smaller than box vents or off-ridge vents, limiting the amount of hot air they can draw from the attic space. For this to be an effective ventilation strategy, most homes will require multiple roof fans to noticeably affect the exhaust from the roof.
Whirlybird roof fans may not be the most efficient way to ventilate a roof, but there are some benefits to using them. First, they are green and eco-friendly because they do not require electricity. With the exception of periodic lubrication of the unit, maintenance is practically not required. And unlike the vents mentioned above, they are pretty quiet even on windy days when wind gusts top 20 mph.
If you’re wondering what that tower-like thing is on your roof, you might be the proud owner of a dome vent!
Dome vents are one of the less common types of roof vents due to their cost, complexity, and because not all of them have the underlying problem they were designed to solve.
The origin of dome vents stems from use in sheds. They were originally designed to get plenty of air into the barn attic to help dry out the hay and other crops stored in the structure. In its original form, the dome deflectors served as exhaust and inlet. However, in modern design and roofing, one of the main reasons for using a dome vent is to provide additional light to the area below the vent.
Dome vents come in a variety of shapes and styles. Some have wooden shutters around the openings to keep out the weather, while others are wide open to maximize the amount of light and air entering the space below.
Many Italianate style homes have domed vents built into the roofline for reuse. First, because they are a form of ventilation. But more importantly, because they add a nice touch to the architectural design of a home. A beautiful vent dome can add character and charm to a dull roofline. Some more elaborate styles of dome vents even have windows and enough room for one or two people to enter. What a fantastic place to spy on the neighbors!
The higher costs associated with building a new dome vent, combined with similar efficiency compared to larger box vents, make dome vents an unnecessary expense for most homeowners. Unless limiting attractiveness is your primary concern, dome vents don’t make much sense.
However, if you need extra roof ventilation and don’t mind paying more to make your home look better, then dome ventilation may be the way to go. Otherwise, a few large vents will do the trick!
4 ventilation solutions for your home
With all the ways you can remove that old, musty air from your attic, it would be remiss not to delve into ways to replace it with new, fresh air from outside.
Exhaust ventilation without supply air is like a bicycle without pedals. The air may move a little, but it won’t get far!
Along with proper exhaust (such as a ridge vent or more box vents), proper supply ventilation ensures fresh air is drawn into the attic and up through the exhaust. This is classic vertical ventilation at its finest! A new stream of fresh air enters, and the old warm air is thrown out.
Unlike an exhaust, there are fewer intake styles to consider for your roof. And in most cases, we strongly recommend the first option from the list.
Soffit Vents (Most popular air intake ventilation)
Soffit ventilation is by far the most popular type of supply and exhaust ventilation of the roof. It makes up half of the most popular intake and exhaust combination; soffit vents (for supply) with a ridge vent (for exhaust).
Air vents are a favorite among home builders and roofers because they are the most cost effective vents. If the style of the home allows it, most new builders include ventilated ceilings in their home plan.
What is soffit ventilation?
Soffits are air vents that are installed directly into the eaves located directly below the roof line. Some people refer to this area as the “roof canopy”.
There are different types of ceilings, but almost all of the most common designs have small openings that allow cool air to enter the attic where it helps push hot air out of the house through the exhaust vent. And don’t worry, the holes in the ceiling are tiny, so unwanted critters won’t be able to get into your home.
Since not all homes are created equal, there are two types of ceiling vents designed for most styles: continuous ceiling vents and single ceiling vents.
Continuous soffit vents are longer and often span the entire eaves of a home. Similar to a ridge vent (which runs the entire length of a roof peak), continuous soffits provide more value for money as the surface area is larger. The larger the surface area, the more air can pass through. Continuous soffits are usually made of vinyl with drilled entry holes. Because they are vinyl, they come in a wide variety of textures and colors to match the look of just about any home.
If continuous soffit vents are like ridge vents in the lock world, then single soffit vents (our second type of soffit vent) are more like box vents. They are smaller, usually rectangular in shape, and are spaced 5 to 6 feet apart along the eaves. Because individual soffits are spaced apart, they are not as efficient as continuous systems as they provide less surface area for air intake.
Whether single style or continuous style suits your home, ventilated ceilings are the backbone of any great vertical ventilation system. Combined with the ridge vent, the ceiling tiles draw a large amount of cool air into the home from under the eaves and then help push the hot air out. When it comes to efficiency, there really is no comparison compared to the following inlets.
Gable ventilation is mainly used with a gable roof because ventilation can be placed on each side of the house. These vents are not as effective on more complex roof styles because crosswinds can be obstructed by rafters, peaks, valleys, dormers, and other parts of the roof.
Gable vents come in all shapes and sizes, the most popular of which is the triangular shape, located directly below the ridge of the roofing system. Sometimes they are made of wood or vinyl, but metal ones are the most popular.
Important: While more surface area for ventilation is generally better when it comes to roofs, care must be taken when combining a gable with any vertical ventilation strategy. We give this warning because cross breezes often interrupt the flow of air from a vertical air intake (such as a soffit) to a vertical outlet (such as a ridge vent). The purpose of using a soffit and ridge vent is lost when gable vents come into play.
Ventilation openings above the fascia
On-fascia vents or over-fascia vents are a new form of roof intake that is designed primarily for roofs that do not have eaves large enough to accommodate ceiling vents. The vent is placed over the front board and gutter and directly under the initial tile layer.
The basic premise of fascia vents is to allow air to enter where the wind hits the roof, as opposed to ceiling vents which rely on air lift.
The strength of the vents above the fascia is questionable due to their small surface area. Although they usually reach the bottom of the roofline, they are only about ½ inch tall. This is a drastic reduction in available airflow compared to the ventilation surface area of the soffit.
Over Fascia vents are recommended for homes where ceiling vents cannot be used, as well as on more complex roofs where the use of ceiling vents by itself would be inadequate.
The pros and cons of a front vent hold true for drip edge vents because they are very similar in design and efficiency. With vents on the fascia and intake lip, the air intake is designed to hit the roof directly and then push cold air up the inside roof wall to any outlets at the top of the roof.
Drainage vents differ from front panel vents due to where they are installed. A drip is a roofing material that fits directly under the first row of tiles and is designed to drain water into the gutters. Usually made of malleable metal. The drip vent includes an inlet into classic roofing material with small holes drilled into the drip itself or attached to the drip as an add-on.
As you can imagine, installation is notoriously tricky and should only be done by a professional.
Like fascia vents, vents are ideal for roofs that cannot use enough soffit vents to draw in air, but are not comparable to soffit vents.
What type of ventilation is best for my roof?
In most cases, we recommend soffit vents for intake and ridge vents for exhaust.
For homes that cannot have ridge ventilation, box vents are generally the second best option for a range hood. And for homes that can’t have ceiling vents, you’ll find fascia vents the second best option.
However, each house is individual. While the best vent for your roof will vary depending on the style of your home and the shape of your roof, we can agree on two things:
First, having both intake and exhaust vents is better than having just one. Secondly, vertical ventilation is much more effective than horizontal or transverse.
If you need a new roof and want to discuss what ventilation strategy is best for your home, we are here to help. Call us at 866-425-7894 or send us a roof quote request.