Roof vents provide essential functions for virtually every type of roof. Without them, your home could suffer significant problems, resulting in thousands of dollars in repairs. But how many roof vents do you really need? Read on to learn the importance of roof vents, along with recommendations for choosing the right type and amount for your home.

Why Are They Necessary?

Roof vents serve several important purposes. For one, they keep your attic a lot cooler during spring and summer. If you’ve ever entered your attic on a warm day, you know this one benefit is a good enough reason to install multiple vents wherever you can. Roof vents also lower the temperature within your attic and promote greater airflow to help prevent rot, mold and many other issues homeowners face if they have unventilated roofs.

But adding roof vents isn’t just about regulating attic temperature. There are many more reasons your home’s roof needs adequate ventilation, including: 

  • Roof vents promote lower energy bills, since good air circulation means your cooling and heating systems won’t have to work as hard or as long. 
  • Roof vents help prevent damage to shingles, since hot attics can crack and damage your shingles, dramatically shortening their lifespans. 
  • Roof vents ensure better airflow, reducing moisture that can build up within an attic. Excessive moisture can cause damage to almost every part of your roof, and poorly ventilated attics tend to develop serious mold growth. 

How Many Do You Really Need?

Now that you recognize the importance of roof vents, you may be wondering how many you actually need. If your roof has a vapor barrier, a general guideline is 1:300, or one square foot of roof vents for approximately every 300 square feet of ceiling space. If your roof does not have a vapor barrier, a better ratio is 1:150, or one square foot of vents for about every 150 square feet.

Ideally, your roof vents should be divided evenly, with half intended for air exhaust and the other half intended for air intake. That means that a 4,200-square-foot home with a moisture barrier should have 16 square feet of roof vents.

With all that said, every house is different, and climate can have an impact. In some cases, your roofing contractor may recommend more vents for your home. 

What Kind of Vents Do You Need?

Since all homes are different, every roof type requires a slightly different strategy for roof vents. Depending on your situation, you may need the following: 

Wind Turbines

This is the traditional roof vent you’ve probably noticed atop countless homes in your neighborhood. Driven by wind power, their spiral design draws the moisture and hot air up and out of a home’s attic.

wind turbine roof vent

Power Vents

These vents have motors that drive small fans to drive out moisture and heat. Some even have humidistats and thermostats to monitor the humidity and temperature levels in your attic. When the readings hit a certain setting, they are programmed to activate. 

Box Vents

These vents use natural convection by providing a simple hole where the rising moisture and hot air can escape. Since box vents don’t use any type of wind or motor, roofers often need to add more than the traditional amount.

Ridge Vents

As the name suggests, ridge vents are located on the horizontal ridge of a home’s roof. Many roofers regard ridge vents as the most efficient roofing system for many types of homes.

Cupola Vents

Cupola vents are so attractive, many homeowners use them as purely decorative additions to their roofs. They can, however, also be functional and are often paired with other styles of vents to provide adequate ventilation. 

Soffit Vents

While not located on the roof, soffit vents are essential for promoting ventilation to your attic. Installed along the soffits around a home, these vents funnel a significant amount of air into the attic. Since they are at the lowest point of the roof, however, they must be paired with other kinds of roof vent to give the hot air a place to escape.

Need a new roof or help repairing weather-related damage? A to Z is ready to help. We’ve developed a widespread reputation as one of Colorado’s premier roofing contractors by providing reliable workmanship and attentive, honest customer service. Contact our team to learn more.