Roof Ventilation Options - Is Active Or Passive Ventilation Better?
Ventilation Is Extremely Important For Maintaining The Health Of Your Roof, But Which Vet System Is Best For Your Property? Read On To Find Out.
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Why Do You Need Roof Ventilation?
Insulation and air sealing are commonly discussed when talking about attic energy efficiency. However, what is not widely mentioned but is equally important is roof ventilation.
Roof ventilation lets your house breathe. This system is comprised of intake and exhaust vents that circulate air. Essentially, this entails pushing unwanted air or hot air out of the attic and bringing outside air in to regulate internal temperatures.
Without the in and out passages of roof ventilation, hot air gets trapped inside your home, which can cause a host of issues in your home.
Proper ventilation is important for the following reasons;
Attic Ventilation Affects Your Roof Lifespan
A roof’s lifespan indicates how many years the roofing materials will last. Depending on the roofing type, this can be anywhere between 25 to 60 years.
How much wear you will actually get from a new roof is dependent on several factors. These include your attic’s ventilation.
Without proper ventilation, the trapped cold or hot air will begin to damage your roof, significantly shortening its lifespan.
For example, poor ventilation will trap heat in the attic during summer. This burns your roof, causes adhesives to deteriorate, and roof shingles to curl or crack.
During winter, moisture and heat from inside the house travel up to the cold attic. This causes condensation, which can make your roof’s decking wavy or cause it to begin to swell.
The decking can also lose its ability to hold nails.
Trapped moisture can also cause mold and mildew. Mold and mildew are not only unsightly, but they can also cause serious health problems to the occupants of a house.
Regardless of whether you have cold or hot air. You will run into problems if you do not have a vent to expel the air from your house.
Ensures Your Warranty Stays Valid
Buying a new roof is expensive. Luckily, there are roof warranties with every purchase.
There are two roof warranties you can get. One is a manufacturer’s warranty, and the second comes from the roofing contractor installing the roof.
The manufacturer’s warranty protects your investment by protecting your roofing materials for their stipulated lifespan. If your roof fails prematurely, then your manufacturer’s warranty can sort it out.
This, however, comes with some terms and conditions. You are supposed to do certain things to ensure your roof functions as it should. This includes having the roof installed professionally, carrying out proper roof maintenance, and so on.
As such, if your roof was to fail due to an inefficient ventilation system, the warranty you have on your roof will be voided. This means you would have to pay out of pocket for the repairs or replacement.
Keeps Your House Habitable In Extreme Weather
In the summer, your vents will inject fresh air into the house and expel hot air from the home. Without proper ventilation, hot air gets trapped in the attic, which causes the rooms under the attic to heat up and even become uninhabitable without any sort of ventilation.
Whenever this happens, your AC has to work harder to cool down the home. This undoubtedly means more energy is used, and of course, higher costs.
Roof Ventilation Options
- Active ventilation
- Passive ventilation
Active Ventilation
This is ventilation provided mechanically by extractor fans, whole-house ventilation systems, and range hoods.
These systems are electricity-powered and the bigger they are, or the more elements they contain, the more energy they consume.
For well-designed, well-insulated homes, it’s possible to only use active vents in areas where moisture is generated only. These include the bathroom, kitchen, and laundry. This can then be supplemented with passive ventilation in other parts of the house.
This type of ventilation can also get warm air in damper, cooler areas like south-facing rooms.
Another thing about active ventilation options is that they provide more consistency because they depend on electricity and not unpredictable natural elements.
Vents in this category include:
Powered Attic Vents
Powered attic vents are also known as powered attic fans or attic power vents. These are electric propelled fans that help pull out stall air from attics. They function much as box fans do in summer.
These vents help maintain your attic temperature at a constant level relative to the rest of your home. In essence, they prevent temperature fluctuations in the attic, which is something you want to avoid because fluctuations cause humidity swings. Humidity swings will create condensation on the walls as the air gets colder due to hot air being able to hold a much higher level of humidity than cold air can. That condensation can eventually turn into mold, leaving you with a health danger in your home.
Solar-Powered Attic Fans
These work much like power attic vents, only that they have built-in solar panels to power the fans. This makes them an upgrade to power attic fans whose biggest letdown is that they guzzle up too much energy to operate.
With solar-powered attic fans, you can save up on energy costs and benefit from federal tax credits and other rebates. There is a wide array of solar-powered fans in the market to choose from. The prices are dependent on size, airflow, installation costs, warranty period, and other variables.
To get one installed, have a Colorado roofing professional carry out an attic inspection first. They can then recommend the solar power fans that will work best for you.
Roof Turbines
Roof turbines, also known as whirlybird turbines, feature an aluminum blade inside a ‘cowl.’ These blades rotate and pull hot air from your attic and out into the environment.
There are active roof turbines that jumpstart the blades to begin spinning. The blades need to spin at about 5 to 6 miles per hour to be effective. Also, most homes will require multiple turbines for them to have the required effect.
This should not worry you too much as roof turbines are excellent at harnessing wind energy from the outside air and wind. It’s a plus that roof turbine blades can be naturally propelled using wind.
The downside is that they might not work as well on non-windy days. The other thing is that their moveable bits start breaking down as the vents age. This can cause the turbines to stop working or make the vents noisy.
Passive Attic Ventilation
Passive attic ventilation utilizes natural methods like air currents and thermal buoyancy to circulate air.
Passive ventilation regulates air temperatures by pushing out the old air and bringing in the fresh air. These vents are more affordable and require significantly lower upkeep costs than most other ventilation types.
This ventilation type is especially effective in homes with a huge indoor vs. outdoor temperature difference. This is because the system circulates hot air, which naturally rises upwards.
Vents in this category include:
Ridge Vents
These are installed across the peak of a roof and are among the most commonly used type of passive attic ventilation.
These vents run across the entire length of the roof. Because of their high placement, their location is ideal for letting hot air escape. They are also hard to see, which is great for aesthetics.
Their length also means they can expend large amounts of hot air simultaneously. These are called ridge vents because they cover the ridge of a roof, which is where the two sides of a roof converge.
Aside from circulating stale air from the attics, ridge vents also keep critters away and prevent precipitation.
Off-Ridge Vents
Metallic off ridge vents are installed on houses whose roofs have three-tab asphalt shingles. They share a similar name with ridge vents because of their placement near the crest of a roof.
Name aside; these vents are more similar to box vents than any other vent type. Off-ridge vents are not as big and do not cover the same range ridge vents do. For this reason, these work best as supplementary vents in a house with other vents. They can also be used on their own in smaller-sized homes.
Off-ridge vents are about 4 feet long and are installed by cutting a hole the size of a vent just below the vent line. Off-ridge vents are also ideal for homes with multiple dormers, peaks, and valleys.
Box Vents
Box vents require you to cut holes on the roof to install. Homeowners will usually install two to three-box vents on their roofs to get adequate ventilation.
Box vents are much smaller than off-ridge and ridge vents, making it possible for homeowners to place them strategically on the roof depending on where they require ventilation.
For people whose roofs have complicated designs, box vents are excellent options.
Your roofer can help you settle on a color that compliments your roof and advise on plastic vs. metallic options.
Soffit Vents
These are installed directly under the eaves of a roof. This is the place right below your roofline, also referred to as the overhang.
Nearly all soffit vents bear small holes to let in cool air so it can circulate in the attic while hot air is pushed out.
You can get continuous soffit vents that cover a longer area. You can also get individual soffit vents arranged in 6 feet intervals on the roof. These vents can also be used alongside ridge and box vents to provide additional vertical ventilation.
Gable Vents
These vents are made of wood and have a screen wire backing. In addition, gable vents are installed on an exterior wall of the attic to provide adequate air circulation in extreme weather conditions.
You can get these in different shapes and sizes, and you can work with your contractor to find one that perfectly fits in with the overall design of your home.
The main way a gable vent works is by allowing air to escape the attic. This prevents moisture build-up during winter and offers cooling in the summer.
These vents are ideal for gable roofs because other roofs can potentially have beams and other structures that would interfere with air movement across the roof.
Which Is The Best Roof Ventilation Option?
There is sadly no direct answer to this question.
The most important element of a roof ventilation system is balanced, adequate airflow. To break this down, this means a system that allows equal amounts of air to enter and exit the attic area.
The correct number of exhaust and intake vents on a roof are arrived at based on the volume and square footage of the attic area. The goal of a ventilation system is to give you clean, fairly cool air while removing moist air.
Therefore, the best ventilation system is one that functions adequately for your house.
Signs Of Poor Roof Ventilation
As with other things in your house, it helps to know when you might have a problem with your roof ventilation so you can take measures to correct the issue early enough.
Here are signs that you might have poor roof ventilation.
Ice Dams And Icicles
When snow piles up on the roof and you spot large ice dams forming, you likely have a problem with your ventilation. Ice dams form when a roof begins heating up, snow starts to melt, and the running water freezes up again at the edge of the roof.
This is a serious problem that might lead to more damage if not looked into.
Your Air Conditioning Constantly Breaks Down
When you have a good-quality air conditioning system that’s properly installed, there is no cause for it to keep breaking down.
Often, people cannot make the connection between a constantly malfunctioning air conditioning system and a poorly working ventilation system. However, the correlation is simple. An inadequate ventilation system forces the air conditioning system to work harder.
For example, on extremely hot days, your A/C works in overdrive to cool the house. This puts a lot of stress on your HVAC system over time, which might cause it to keep breaking down.
Roof Leaks, Mold And Mildew
Poor roof ventilation can cause water damage. Aside from water seeping into the roof, water and moisture can cause mold and mildew on the roof or attic. If not dealt with immediately, these can further damage your home and lead to unnecessary roof repairs, which will lower the value of your home.
Mold and mildew are also known to affect air quality and cause a myriad of health issues, more notably, respiratory problems.
Speak With One Of Our Roof Ventilation Experts
If you are trying to figure out which roof ventilation options are best suited for your home or commercial property, give us a call. Overhead Roofing Of Colorado Springs would be happy to come out and do a thorough inspection of your roof and attic to determine the optimal ventilation system and number of vents needed. Our experts will go over options with you so we can find the perfect solution to maximize the lifespan of your roof and prevent mold and mildew from forming in your attic. Our inspections and estimates are always free, so don’t hesitate to give us a call!
Interested in learning more about roofing? Check out our in depth blog packed with helpful roofing resources and information.
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