A Quick Guide to Roof Ventilation

Mar 16, 2023


Viking Contractors




March 16, 2023


May 10, 2024

Got Questions?

If you’re like most homeowners, your roof ventilation system needs to be added to the top of your daily list. However, it plays an integral role in keeping your home a safe living environment and contributing to the longevity of your roof, so maintaining its condition should be your priority. 

This article will explain roof ventilation systems and the science behind them. We’ll also discuss their benefits and help you make informed decisions when installing one for your home.

How Does Roof Ventilation Work?

Roof ventilation can either be a system of vents or openings functioning passively or a mechanical system operating actively to allow air to flow freely through the attic or roof space. 

Hot air is less dense and floats upward. In warmer weather, heat that is accumulating under your roof can radiate downwards and heat your interior, making for uncomfortable and uneven temperatures. It can also transfer to your wood framing and the back of your roof, potentially damaging the material and underlying structure.

Alternatively, in cooler weather, it can contribute to a build-up of mold and rot through the accumulation of moisture, all of which pose a risk to your family’s health and home structure.

Roof ventilation ensures that warmer air can escape and cooler air can come in from the outside.

What Are The Types of Roof Ventilation?

There are two roof ventilation systems, passive (natural) and active (mechanical). Let’s explore them in more detail.

  • Passive Ventilation: It involves the use of several openings or vents throughout your roof. Installing it in a way that allows hot air to get out and for cooler air to enter. It doesn’t require any machinery. As such, it’s a cost-effective option that has several advantages.
  • Active Ventilation: It involves using a special system of fans and exhausts designed to pump hot air out of your home and bring in cooler air. This requires a constant source of power to function.

Which Type of Roof Ventilation Is For Me?

A suitable roof ventilation type depends on the design of your home and where it’s situated.

Homes built with natural air circulation don’t require a mechanical roof ventilation system. Typically, houses with minimal obstructions to allow air to flow freely, well-insulated, and use materials with high thermal mass are a good match for passive ventilation systems.

Houses in regions with stable temperatures and humidity can also benefit from a passive ventilation system. 

Passive ventilation may not be ideal for homes where natural airflow is obstructed due to its size or design. If you notice a difference in temperature across the rooms in your house or if you find the mold and rot indoors, mechanical ventilation is better suited for you. This type of system is also suitable in regions with heavy air pollution.

Pros and Cons of Roof Ventilation

Each type has its advantages and disadvantages. Let’s have a closer look.

Passive Roof Ventilation

Roof Ventilation - Static vent installed on a shingle roof for passive attic ventilation


  • Energy-efficient
  • Easy to install and maintain
  • Less noisy
  • Can work with other ventilation systems, such as ridge vents, for improved ventilation


  • Relies heavily on weather conditions and home design to function optimally
  • Less effective at removing hot, moist air than mechanical systems
  • Requires proper installation to function properly

Active Roof Ventilation


  • Quick and excellent at removing hot air from your attic space, protecting your roof, and making your home interior comfortable
  • Adjustable ventilation levels
  • Can work with other ventilation systems
  • Suitable for homes of any design and location


  • Costly monthly electric bills.
  • Expensive to install and maintain.
  • It can be quite noisy.

What Are The Benefits of Roof Ventilation?

A good roof ventilation system that’s properly functioning can help improve the comfort of your home’s interior and extend the life of your roof. How?

  • Roof ventilation allows hot, moist air to escape from your attic space, helping stop mold growth.
  • It prevents the build-up of dangerous fungi and rot, ensuring the longevity of your roof and underlying structure.
  • Helps regulate your home’s temperature, saving you from resulting to heaters and ACs and, consequently, saving you energy costs.

Thermometer inside house cross-section

How Can I Tell My Roof Ventilation is Malfunctioning?

There are several ways to tell whether your roof ventilation system works optimally.

Differences in temperatures across rooms or malfunctioning ACs could be a sign. When HVACs overwork to compensate for the poor temperature regulation, they can rack up energy bills and shut down often.

You should also check your attic. Mold, mildew, leaks, or rot are signs of trouble. Ice dams are also a result of poor ventilation. This refrozen water can cause leaks and damage your roof.

If your roof has damage, you should immediately consider repairing your system. If it isn’t, but you notice any of these signs, have it undergo system maintenance to avoid future issues.

How To Calculate Roof Ventilation?

Calculating your roof ventilation needs may be difficult, so we recommend leaving it to a professional. They’ll inspect your home and find an appropriate ventilation solution according to a few factors, including:

  • The type and size of your roof space and general home design
  • The recommended ventilation rate, based on your area’s climate and local building codes
  • The type of ventilation system you need and the required number of vents

Hiring a professional will help ensure precise calculations, proper installation, and optimal function of your roof ventilation system.


Your roof ventilation system is integral to ensuring your comfort and protection. It regulates your interior’s temperature and prevents the build-up of dangerous fungi that can damage your home’s underlying structure. So, it’s best to keep it well-maintained and functioning well.

Contacting a professional should be your first step to guaranteeing that. They can also help you determine what’s suitable for your needs, make any necessary repairs, and advise you on how to maintain your ventilation system.

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