People often talk about air sealing and insulation when it comes to attic energy efficiency, but ventilation is equally as important.

This is because attic ventilation helps push hot or unwanted air out of your attic and keeps the internal temperature consistent by bringing outside air in.

In this article, we’ll discuss why you need attic ventilation and its most common types to help you find the right one for your home.

Key Takeaways

  • Attic ventilation systems help regulate the temperature and moisture levels in your attic, improving energy efficiency and preventing damage to your roof.
  • There are two main types of attic ventilation systems: passive and active. Passive systems use natural airflow to ventilate the attic, while active systems use fans or other mechanical means to circulate air.
  • Common passive ventilation systems include soffit vents, ridge vents, gable vents, and dormer vents. Each type has advantages and disadvantages, depending on factors such as the shape and size of your roof.
  • Active ventilation systems include powered attic fans, which can be mounted on the roof or in the gable of your home. These fans can be controlled manually or automatically and can help improve ventilation in areas where natural airflow is limited.
  • It’s important to ensure that your attic ventilation system is properly designed and installed for optimal performance. This may involve consulting with a professional roofing contractor or another ventilation expert.

Types of Attic Ventilation

Before we get into the most common types, it’s essential to understand the two different categories of attic ventilation.

Attic ventilation can be split into either active or passive categories.

Active Ventilation

Active ventilation is a system that provides indoor air circulation through mechanical fans. These types of ventilation are key for areas prone to moisture buildup or spaces that collect excess heat, like attics and garages.

It also keeps your home from gases and other harmful contaminants in areas where chemicals, equipment, or cars are stored.

Active ventilation provides more consistent air circulation since it doesn’t rely on natural winds. Solar-powered ventilation systems are particularly useful since it runs on the sun’s energy instead of electricity.

Passive Ventilation

Passive or natural ventilation is a system that uses natural methods like thermal buoyancy and air currents to provide air circulation. They typically use air vents to control the intake of air.

Passive ventilation helps regulate air temperature while bringing in the fresh air and pushing out the old air. They’re cheaper than other types of ventilation and require far less upkeep.

It’s particularly useful in homes with a big difference between indoor and outdoor temperatures since hot air rises and will be circulated out by the passive system.

Why You Need Proper Ventilation

Why You Need Proper Ventilation

But why do you need proper ventilation in the first place?

For starters, ventilation protects your roof from things like ice dams.

Ventilation reduces moisture in places like your attic. Too much moisture in your attic can cause ice to melt and then refreeze on your roofs in the winter. This causes permanent damage to your roof and compromises your overall building envelope.

Improper ventilation causes poor indoor air quality from dead air, leading to stuffier attics. It also forces your HVAC systems to work harder since hot air isn’t properly moving out of your home.

Generally speaking, if you want a more comfortable home, attic ventilation is crucial. Keeping hot or contaminated air requires proper passive or active ventilation.

Let’s now look at the most common types of ventilation across both categories.

Types of Passive Attic Ventilation

Ridge Vents

Ridge Vents

Ridge vents are one of the most common types of passive attic ventilation. They’re typically installed across the peak of the roof.

They usually run across the entire length of the roof. Because they’re installed on the highest point or the peak, they’re in the best position for letting hot air escape. Their length also allows them to expel large amounts of air.

Most, if not all, contractors are familiar with ridge vents because of how common they are in American homes. It’s one of the most effective passive attic ventilation since it leverages the natural flow of hot and cold air inside a home.

Off-Ridge Vents

Off Ridge Vents

Metal off-ridge vents are installed on roofs with three-tab asphalt shingles. They share a similar name with ridge vents mostly because they’re placed near the roof’s crest.

If anything, off-ridge vents are more akin to box vents than ridge vents. They’re not as big and can’t cover as wide of a range as ridge vents, but they might work better on smaller homes or ones trying to increase the amount of ventilation they already have.

They’re typically about 4 feet long and involve cutting a hole the size of the vent about a foot below the vent line. Off-ridge vents are perfect for homes with many peaks, valleys, and dormers.

Box Vents

Box Vents

Box vents are another popular form of passive ventilation similar to off-ridge vents. Box vents also require you to cut holes in your roof. Homeowners typically install two or three box vents on their roofs for maximum ventilation.

Their small size allows homeowners to install box vents in specific areas on their rooftops, unlike ridge or off-ridge vents. This means you can be more strategic about where you place your box roofs depending on which areas need ventilation.

Box vents are a perfect choice if you have a hipped roof or some other complicated roof design.

Soffit Vents

Soffit Vents

Soffit vents are installed directly under the eaves of your roof, located underneath your roofline, also known as the overhang. Almost all soffit vents have small holes that allow cool air to circulate into your attic while pushing hot air out.

There are continuous soffit vents, which cover a longer area, and individual soffit vents, placed in six feet intervals. Soffit vents are excellent additions to your ridge or box vents because they provide additional vertical ventilation to your attic.

Gable Vents

Gable Vents

Gable vents are usually installed on the exterior wall of your attic to create proper air circulation during extreme climate conditions. They come in various shapes and sizes depending on the builder and the design of your home.

Often, they are made out of wood and have screen wire for the backing. The sole function of a gable vent is to all hot air to escape the attic. This prevents moisture build-up in the winter and some cooling relief in the summer.

Types of Active Attic Ventilation

Powered Attic Vents

Powered Attic Vents

Powered attic vents – also known as attic power vents or powered attic fans, are electric-propelled fans that help pull stale air out of the attic. They work similarly to a box fan on a hot summer day by pulling hot air out of your attic.

In terms of how powered attic vents fit into your overall ventilation strategy, it helps keep your attic at a constant temperature relative to the rest of your home. You want to avoid extreme temperature fluctuations, which powered attic vents are particularly good at.

Some detractors claim powered attic vents use up too much electricity. This concern has led to more adoption and implementation of solar-powered attic ventilation systems to provide the same cooling benefit without electrical dependence.

Solar-Powered Attic Fans

Solar Attic Fan

Solar-powered attic fans do away with the previously mentioned energy concerns that come with an electric-powered attic fan.

They work in the same fashion as a powered attic vent, except they have built-in solar panels to harness energy to power the fan. This provides cooling benefits without the added power costs. They also qualify for federal tax credits and many other rebates.

There are a wide variety of solar-powered attic fans on the market. Pricing ultimately depends on installation costs, size, airflow, manufacturer, warranty period, and other variables.

If you want to add a solar-powered attic fan, we recommend scheduling an attic inspection first. An attic expert will be able to assess how many fans you need and where the fan should be installed. They can also make other recommendations to ensure that your solar fan provides the most benefit.

Check out our post the best solar powered attic fans.

Roof Turbines

Roof Turbines

Roof turbines, or whirlybird turbines, use aluminum blades inside of a “cowl” to rotate and ultimately pull hot air out of your attic and out into the air. There are active roof turbines that can jumpstart the blades to start spinning.

Turbine blades need to spin at about 5 to 6 miles per hour to be effective, and most homes will need multiple roof turbines to have a noticeable effect. However, roof turbines are great at harnessing wind energy from electricity and the outside air since the blades can be naturally propelled using wind.


What are the three kinds of attic ventilation?

The three types of attic ventilation are:

  1. Static Ventilation: Ridge and gable vents are examples of static ventilation. These ventilation systems rely on natural convection to circulate air in the attic.
  2. Powered Ventilation: Powered ventilation involves using electrically powered fans or turbines to draw air into and out of the attic. This type of ventilation includes roof-mounted exhaust fans, gable-mounted exhaust fans, and solar-powered attic fans.
  3. Mechanical Ventilation: Mechanical ventilation involves using mechanical devices, such as heat recovery ventilators or air-to-air exchangers, to circulate air in the attic. These systems are often more complex and require professional installation.

What are the most common attic ventilation methods?

The most common methods of attic ventilation are:

  1. Ridge Ventilation: This method involves installing a continuous ridge vent along the roof’s peak to allow warm air to escape from the attic while drawing in cool air from the eaves.
  2. Soffit Ventilation: This method involves installing vents in the soffit or underside of the eaves to allow cool air to enter the attic while warm air is expelled through higher vents.
  3. Gable Ventilation: This method involves installing vents on the gable ends of the attic to allow air to circulate from one end of the attic to the other, promoting ventilation.
  4. Roof-Mounted Exhaust Fans: This method involves installing exhaust fans on the roof of the house to draw warm air out of the attic and expel it outside.
  5. Solar-Powered Attic Fans: This method involves installing solar-powered fans on the roof of the house to draw warm air out of the attic and expel it outside using solar power.
  6. Turbine Vents: This method involves installing turbine vents on the house’s roof, powered by the wind, to draw warm air out of the attic and expel it outside.

Proper attic ventilation is important to prevent problems such as mold growth, roof damage, and energy loss. The specific method of ventilation that works best for a particular home will depend on factors such as the home’s size, location, and climate. It’s recommended to consult with a professional to determine the best method of attic ventilation for a specific home.

Leverage Attic Ventilation Today

Installing attic ventilation isn’t just about keeping your attic cool – it can positively affect your roof’s lifespan and improve your overall home energy efficiency. Use this article to find the right type of attic ventilation and take advantage of their benefits today.

Every summer, homeowners face the same dilemma of keeping their homes cool without breaking the bank on their energy bills, with the average energy bill totaling about $137 a month.

Many homeowners don’t know that their attics can be a big culprit in wasting energy.

Key Takeaways

  • Cooling an attic properly can help reduce energy bills by reducing the heat that radiates into the lower living spaces.
  • One way to cool an attic is through air sealing, which involves finding and closing air leakage points to prevent cool air from escaping and hot air from entering.
  • Insulating the attic can also help cool it by creating barriers between the roof, the attic, and between the attic floor, and the rest of the home. Insulation reduces heat transfer and prevents cool air from escaping.
  • Another way to cool an attic is through ventilation, which allows hot air to escape and cool air to enter. A solar attic fan can be a good solution as it runs on energy from the sun and provides efficient and cost-effective ventilation.
  • Before taking any action to cool an attic, it’s recommended to inspect the attic for any potential issues, such as cracks in the foundation, and to follow local building codes and safety precautions.
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Heat often collects in the attic from the roof and radiates into the lower living spaces. This forces homeowners to crank up the AC, raising energy bills. So, what can you do?

Luckily, there are several ways homeowners can cool their attics and make their homes more energy-efficient. You can finally cool your attic the right way through air sealing, insulation, or ventilation.

Air Seal

One of the easiest and best ways to help cool down a hot attic is with proper air sealing. This is particularly effective when used in tandem with insulation and other strategies.

What is Air Sealing?

Air sealing is finding and closing air leakage points in and around your home. This is usually your attic walls, floors, entrances, and spots in between ventilation units. These pockets of air leakage can be big or small, accounting for over 40% of all energy lost in your home.

For more information on attic air sealing, including cost savings, check out our guide: Is Air Sealing the Attic Worth It?

How Air Sealing Cools Your Attic

How Air Sealing Cools Your Attic

By properly air sealing your attic, you’ll prevent cool air generated by your AC units from escaping to your attic. It’ll also prevent heat and warm air in the attic from radiating down into the lower levels.

It also prevents the formation of ice dams on your roofs in the winter. This is relevant in the summer because ice dams can cause moisture buildup, damaging your attic insulation. If your insulation is weak or insufficient, your attic will allow more heat to transfer into your home in the hot summer months.

How to Air Seal Your Attic

Before You Start

If you can, obtain or create a sketch of your attic. This will help you pinpoint areas of air leakage. Pay close attention to areas like dropped soffits over kitchen cabinets, slanted ceilings over stairways, areas where the walls and ceilings meet, and other dropped-ceiling areas.

See where your attic is leaking air. Schedule a free attic inspection.

Wiring holes, gaps near plumbing and pipes, and recessed lights are also common areas for attic air leakage. Write down these spots and ensure you have the right equipment to seal them.

Alternatively, we recommend getting a professional attic inspection completed by a licensed contractor. This will provide you with detailed insights, including thermal images of your attic. Use an attic inspector’s experience and professional equipment to pinpoint the exact spots where unwanted heat transfer is taking place.

Air Sealing the Attic

Start by filling in the big holes. You can do this by wrapping insulation in plastic bags and plugging areas like open stud cavities, ensuring it fits tightly.

For dropped soffits, remove the insulation and add a piece of reflective foil or rigid foam board a few inches longer than the opening. Seal it in place using caulk or other adhesives.

For pipes that have small air pockets, use caulk or foam to fill the space around them. Make sure you seal the attic hatch with new wood stops and adhesive foam weather strips.

Add Insulation

Attic Insulation

Insulation is usually the most common method of cooling your attic and preventing the heat from transferring downstairs. It prevents heat from radiating downwards while keeping cool air from escaping to the attic.

What is Attic Insulation?

Attic insulation creates barriers between the roof and your attic and the attic floor to the rest of the home. It comes in various materials, including fiberglass, cellulose, and even reflective surfaces similar to foil.

How Insulation Cools Your Attic

Insulation keeps the sun’s heat from radiating into the lower floors, meaning your home will be noticeably cooler. This means your AC won’t have to work quite as hard to maintain a cool internal temperature.

Insulation also prevents cool air from downstairs from escaping into the stuffy attic since it reduces the movement of air. The EPA estimates that you can save over 15% on your annual energy bills by adding insulation to your attics and other areas.

How to Apply Attic Insulation

Before You Start

Always check your local building code’s recommended R-values or your insulation’s ability to reduce conductive heat flow. It’s also recommended that you seal any air holes prior to installing insulation.

Take note of areas in your attic with plumbing, ductwork, and wiring. For your own safety, make sure there aren’t any cracks in your attic’s foundation.

If you’re applying rolled-up batts or reflective insulation, make all the necessary measurements, so your insulation fits properly. Purchase safety goggles and masks since materials like fiberglass can be dangerous to your lungs and eyes.

Insulating an Attic

If you’re using batt or roll insulation, target areas like your skylights and cut out the necessary amount of insulation. You can secure it between the framings with staples and house wrap.

Get an attic insulation estimate. Schedule a free attic inspection.

Make sure not to compress the insulation, or it’ll become less effective. Whether it’s the stud walls or the joists, make sure you gently fit the insulation without leaving any gaps.

If you’re using blown-in insulation, plug in the machine and feed half a bag of insulation into it. Turn the machine on and fill any areas that need insulation. Be careful not to spray the loose fill in the rafter vents.

Reflective insulation requires you to measure the surface area of the places you’re covering and staple the material to the wood.

Add Ventilation

Ventilation allows your home to breathe. In the attic, it pulls fresh air through it and lets the heat escape regularly. Let’s explore how attic ventilation works to cool down your home.

What is Attic Ventilation?

A balanced ventilation system occurs when the amount of air entering the attic equals the amount leaving it. The cooler air from the intake vents pushes the warm air up and out through the exhaust vents near the ridge.

Without proper intake ventilation, the exhaust vents don’t work, and the heat doesn’t have a way to escape. This can cause permanent damage to your roof, which, as we discussed, can damage your attic insulation and affect your home temperature.

How Attic Ventilation Cools Your Home

How Attic Ventilation Cools Your Home

In the summer, an improperly vented attic can cause many problems. Without proper ventilation, the heat in your attic has nowhere to go. This means your upstairs rooms will be uncomfortably hot until the sun goes down.

As such, poor ventilation causes hotter attics. This means hotter upstairs rooms and more stress on your AC units. By installing proper ventilation and letting the air circulate in and out of your attic, less heat will be trapped.

How to Ventilate Your Attic

Before You Start

First, look for signs of poor ventilation by either looking at your home yourself or calling a contractor. These signs include:

  • Curling shingles
  • Roof damage
  • Excessive attic heat
  • High summer energy bills
  • Rust on metal components in the attic

Keep in mind that every attic has different ventilation needs. Calculate the right amount of ventilation for your attic beforehand. There are a few different equations you can use to determine this number.

Ventilating an Attic

Generally speaking, installing attic ventilation isn’t a DIY project. You should call a trusted professional to install the different types of attic ventilation common in most homes.

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There are several different types of attic vents that you can use to improve the air circulation in your attic. These include turbine vents that can remove over 300 cubic feet of air a minute.

Active, power vents are smaller vents that can pull hot air out of the attic using electricity or solar power. Passive vents, such as box vents or ridge vents, can use natural winds and convection to move air through your attic.

Lower Your Energy Bills With Cooler Attics

Your attic is a literal hotspot for summer heat, but that doesn’t mean you have to break the bank trying to pay your energy bills. Leverage the three different strategies in this article to create a much more energy-efficient attic today.

Attics are arguably the most susceptible to mold because of roof leaks, poor air sealing, and ventilation issues.

However, getting rid of attic mold, especially when it grows on plywood, is a tricky endeavor that most homeowners aren’t equipped to handle. Attic mold can impact indoor air quality and your family’s health, making its removal a top priority.

This article will outline everything you need to know about removing mold from your attic plywood and how to go about it safely and efficiently. Let’s dive in.

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Signs of Attic Mold

Signs of Attic Mold

Routinely checking your attic for signs of mold will allow you to identify any problems and avoid panic scenarios. With that said, you’ll still need to know exactly what signs to look for.

Dark Staining

If your attic plywood has dark stains or black discolorations where it’s clear that the problem has moved beyond just moisture, it’s probably mold.

Hot and Stuffy Attic

Ideally, your attic should be cool and well-ventilated. If it’s starting to feel stuffy and hot, that’s a sign of poor ventilation, which frequently causes mold.

Frost Buildup on Roof Sheathing

During the winter, improper ventilation can cause water vapor underneath your roof to freeze. In time, this frost buildup will cause mold.

The Smell of Mildew

If you’ve got a sharp nose, you’ll likely be able to smell musty or moldy surfaces in your attic. Trust your instincts and spot these. Read our detailed post for more information on what mold smells like.

Wet Insulation

If your attic insulation is getting damp, it’s a surefire sign that your attic is far too moist and mold might already exist. It also damages the insulation, increasing the chance of mold in the future.

What Causes Attic Mold?

What Causes Attic Mold

Generally speaking, if you have a mold problem, you most likely have a moisture problem. If your attic plywood is accruing mold, you first need to address the moisture in your attic.

Poor ventilation, air leakages, and roof leaks often cause this issue.

Blocked Ventilation

Attics usually have a passive ventilation system that lets outside air come through soffit vents and then leaves through the can or ridge vents on the top of the roof.

However, if one of these mechanisms becomes blocked, it disrupts the entire system. Warm air stagnates in the attic, then condenses with the cold wood sheathings in the attic. This creates moisture, leading to mold.

Air Leaks

In leaky homes, the air that’s driven by exhaust fans or the wind can blow through ceilings and attic floors. Because this air often contains water vapor, large-scale air leaks can cause condensation, which leads to mold on your attic plywood.

Roof Leaks

Roof leaks will cause mold to form in specific areas of your attic. Check for any wood discoloration and roof valleys. Roof leaks typically occur in chimneys, vents, or elsewhere where dissimilar materials join together.

How to Remove Mold from Attic Plywood

How to Remove Mold from Attic Plywood

Mold growth on attic plywood is a common problem that homeowners need help with.

Mold not only looks unsightly, but it can also pose a health risk to you and your family. If you have mold growing on your attic plywood, removing it as soon as possible is important. Here is a step-by-step guide on how to remove mold from attic plywood.

Materials needed:

  • Protective gear (gloves, mask, goggles, and long-sleeved clothing)
  • Plastic sheeting
  • Bleach or mold remover solution
  • Spray bottle
  • Scrub brush
  • Bucket
  • Water
  • Fan or dehumidifier

Step 1: Prepare the Area

Before removing the mold, it is vital to take some precautions to prevent the spread of mold spores to other areas of your home. Wear protective gear such as gloves, a mask, and goggles. Cover the floor and nearby items with plastic sheeting to protect them from the mold removal solution. You should also ensure that the attic is well-ventilated by opening windows or using a fan.

Step 2: Mix the Mold Removal Solution

Mix a mold removal solution in a spray bottle. You can use a bleach solution (1 part bleach to 10 parts water) or a commercial mold remover solution. Make sure to follow the manufacturer’s instructions on the label for the proper dilution rate.

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Step 3: Spray the Moldy Plywood

Spray the moldy areas of the plywood with the mold removal solution. Make sure to saturate the moldy areas thoroughly. Allow the solution to sit on the mold for at least 15 minutes to kill the mold spores.

Step 4: Scrub the Plywood

Using a scrub brush, scrub the moldy plywood to remove the mold. Scrub in a circular motion, applying firm pressure to remove the mold. Rinse the brush frequently with the mold removal solution to prevent the spreading of the mold to other areas.

Step 5: Rinse the Plywood

After you have removed the mold and rinse the plywood with clean water, use a bucket of water and a clean cloth or sponge to rinse the plywood thoroughly. Make sure to remove all the mold removal solution and any remaining mold spores.

Step 6: Dry the Plywood

Allow the plywood to dry completely. You can use a fan or dehumidifier to speed up the drying process. Make sure the attic is well-ventilated during the drying process.

Step 7: Inspect the Area

After the plywood has dried, inspect the area for any remaining mold. If you see any remaining mold, repeat the process of spraying the area with the mold removal solution and scrubbing the plywood.

Removing mold from attic plywood is relatively simple if you follow the steps above. It is important to take precautions and wear protective gear when removing mold to prevent health risks. Make sure to take steps to prevent mold growth in your attic by fixing any leaks or moisture problems.

How to Prevent Attic Mold

How to Prevent Attic Mold

Preventing attic mold involves controlling moisture levels in your attic. Here are some tips that can help you prevent attic mold:

  1. Improve ventilation: Make sure your attic is well-ventilated to allow moisture to escape. This can be done by installing vents in the roof and soffit and ensuring they are not blocked by insulation or other materials.
  2. Insulate properly: Proper insulation can prevent warm, moist air from reaching cold surfaces, such as the roof deck, where it can condense and lead to mold growth. Ensure your attic is properly insulated and there are no gaps or voids in the insulation.
  3. Use a dehumidifier: If your attic has high humidity levels, consider using a dehumidifier to remove excess moisture from the air.
  4. Seal air leaks: Check for leaks around the attic’s chimneys, vents, and other penetrations. Use caulking or foam sealant to seal these leaks to prevent warm, moist air from entering the attic.
  5. Monitor humidity levels: Keep an eye on the humidity levels in your attic using a hygrometer. The ideal humidity level for an attic is between 30-50%.
  6. Regularly inspect your roof: Inspect your roof for any leaks or damage. Any water infiltration can increase humidity and promote mold growth.

Following these tips can reduce the risk of mold growth in your attic and maintain a healthy home environment.


Removing mold from your attic plywood is a step towards a cleaner, safer, and more energy-efficient home. When dealing with serious mold problems, hire a professional indoor air quality (IAQ) consultant or mold remediation contractors. Please don’t leave it to chance.

And remember, after removal, be sure to get to the source of the problem. Schedule an attic inspection and learn how to make your attic healthier and energy efficient.