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 be discussing why you need attic ventilation as well as its most common types to help you find the right one for your home.

Types of Attic Ventilation

Before we get into the most common types, it’s important 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 that are prone to moisture buildup or spaces that collect excess heat like attics and garages.

It also keeps your home free of 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 to operate. 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 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 where there’s 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. If there’s too much moisture in your attic, it can cause ice to melt 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 take a 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 crest of the roof.

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 might work better on smaller homes or ones that are 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 lots of 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 to 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.

If you have a hipped roof or some other complicated roof design, box vents are a perfect choice.

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, which are placed in six feet intervals. Soffit vents are excellent additions to your ridge or box vents in that they provide additional vertical ventilation to your attic.

Gable Vents

Gable Vents

Gable vents are usually installed on the exterior wall of your attic in order to create proper air circulation during extreme climate conditions. They come in various different 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 how 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 up there, 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 are interested in adding 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 will also be able to 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 really have a noticeable effect. However, roof turbines are great at harnessing wind energy from both electricity and the outside air since the blades can be naturally propelled using wind.

Leverage Attic Ventilation Today

Installing attic ventilation isn’t just about keeping your attic cool – it can have positive effects on your roof’s lifespan as well as improving 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 trying to keep their homes cool without breaking the bank on their energy bills, with the average energy bill totaling about $137 a month.

What many homeowners don’t know is that their attics can be a big culprit to wasting energy.

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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. Through air sealing, insulation, or ventilation, you can finally cool your attic the right way.

Air Sealing

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 the process of finding and closing air leakage points in and around your home. In your attic, this is usually your 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 which damages 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 these spots down and make sure you have the right equipment to seal them.

Alternatively, we recommend getting a professional attic inspection complete 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, making sure it fits tightly.

For dropped soffits, remove the insulation and add a piece of reflective foil or rigid foam board that’s 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 as well with new wood stops and adhesive foam weather strips.

Attic Insulation

Attic Insulation

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

What is Attic Insulation?

Attic insulation creates barriers between the roof and your attic, as well as the attic floor to the rest of the home. It comes in a variety of 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. Overall, the EPA estimates that you can save over 15% on your annual energy bills just by adding insulation to your attics and other areas.

How to Apply Attic Insulation

Before You Start

Always check your local building code 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 else 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 out the surface area of the places you’re covering and stapling the material to the wood.

Attic Ventilation

Ventilation allows your home to breathe. In the attic, it pulls fresh air through it and lets the heat escape on a regular basis. 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 coming into 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 generate a lot of heat through hot outside air having 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 in the attic.

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 ventilation 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.

Best Solar Attic Fans

Best Solar Attic Fans

Check out our list of the best solar powered attic fans.

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 areas 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 themselves. Attic mold can impact indoor air quality and your family’s health, making its removal a top priority.

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In this article, we’ll be outlining 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.

Attics and More is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

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 out. Read our detailed post 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 first.

This issue is often caused by poor ventilation, air leakages, and roof leaks.

Blocked Ventilation

Attics usually have a passive ventilation system that lets outside air come through soffit vents 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. Chimneys, vents, or anywhere else in which dissimilar materials join together are where roof leaks typically occur.

How to Remove Mold from Attic Plywood

How to Remove Mold from Attic Plywood

Removing mold from your attic plywood is not a simple weekend DIY job. Although you can certainly do it yourself if you’re willing to put in the manhours and purchase the equipment, we recommend contacting professionals to do it unless it’s only a few pieces of plywood that have mold.

For Small Removal Projects – Use a Wet Vacuum or Spray

If you have mold on your attic plywood in small areas, you can remove it yourself so long as it’s collecting in a small area (up to 10 square feet).

Mold Removal Safety Precautions

If you have to remove mold concentrations or perform any black mold removal covering more than a few square feet, we recommend you take these precautions:

  • Wear old clothes and shoes that you can launder or throw away after the cleanup work.
  • Wear special N-95 or P-100 respirators, in addition to goggles and gloves.
  • Set an old box fan or a cheap new one in a window to ventilate the room while working.
  • Wrap and tape moldy contaminants in 6-mm plastic, and double-bag mold-infested debris in garbage bags for disposal.
  • To control airborne spores, moisten moldy areas with a garden sprayer while you work.

You can get rid of mold-contaminated wooden surfaces using a wet vacuum that can fill its tank partially with water to control mold residue. Wipe the surface with a damp sponge or cloth that’s been treated with clean water or wood cleaner.

Once the surfaces have been thoroughly dried, use a HEPA vacuum cleaner on the plywood and safely dispose of all the contents by putting them in well-sealed plastic bags. Any contaminated material, including mold-infested insulation, should be sealed in plastic and disposed of as regular waste.

Hepa Vac for Attic Mold Removal

Vacmaster Pro Hepa Filtration Wet/Dry Vac

The Vacmaster Pro is a certified HEPA system & has an ultra quiet 2-stage industrial motor. It features 4 levels of filtration including a HEPA Cartridge filter, microfiber pre-filter, high-efficiency fine dust filter bag with closure flap, & an exhaust filter-all for HEPA compliance.

Beyond using this vacuum to remove mold from your attic, you’ll find it convenient for cleaning floors, curtains and other areas that collect a lot dust and debris on a day to day basis.

If you have attic mold in multiple areas and it exceeds 10 square feet, we recommend that you contact a mold remediation company to take a look at your attic and decide the best course of action.

For Larger Removal Projects – Hire a Professional Mold Remediation Company

It goes without saying that attic mold removal is no walk in the park for any homeowner. Not only does the possibility of falling through the attic floor make it an extremely dangerous undertaking, but you’ll also need to purchase plenty of expensive equipment to pull it off.

Attic mold removal is therefore borderline impractical for homeowners, even those with plenty of DIY experience because of the dangers it presents. Even if you manage to do it safely, there’s no guarantee that you covered all the bases given all the variables.

Because mold presents serious health concerns while also damaging your home’s overall energy efficiency, we believe this is a job you shouldn’t have to gamble on. If you hire a professional, you can give you and your family peace of mind knowing that the mold was assessed correctly and removed from your attic plywood using the right methods.

How to Remove Mold Stains in Attic

Once you’ve effectively removed the mold from your attic plywood, you may want to remove the unsightly stains left behind.

There are a number of different mold removal products out on the market that you can use and apply to remove even the most stubborn stains in just seconds.

RMR-86 Attic Mold Stain Remover

RMR-86

If you’re looking for an extra strong mold stain removal solution, we recommend using RMR-86 Pro Instant Mold Stain & Mildew Stain Remover. This is a staple for contractors and is safe to use on a number of surfaces including attics, crawl spaces, wood, drywall, and more.

RMR-86 uses an ultra strong formula that instantly dissolves difficult mold and mildew stains without scrubbing or sanding to get the job done quickly and efficiently, saving you both time and money.

Read our full RMR-86 Mold Remover Review.

How to Prevent Attic Mold

How to Prevent Attic Mold

Once you’ve removed mold from your attic, you’ll still need to take care of the root cause if you want to keep it out of your home. In this section, we’ll be exploring how to properly air seal and ventilate your attic to keep it cool and dry.

Air Seal

When air sealing your attic, it’s best to cover up the big holes before caulking smaller spots. For information on the best caulk products for air sealing, check out this post.

You can fill large gaps by placing a 16-inch piece of fiberglass insulation and place it in a 13-gallon plastic bag. Fold the bag once and place it in an open stud cavity. To find the cavity, you’ll need to dig through some insulation in your attic floor.

Need help indentifying air leaks in your attic? Schedule a free attic inspection.

Once you’ve filled the cavities with the insulation bag, place foil insulation over top. Cover it back with the insulation you removed earlier.

Plumbing pipes and small openings for wires are tiny areas that still leak plenty of air in your attic. Seal these holes stuffing small pieces of fiberglass insulation and cover them with expanding foam insulation. Electrical junction boxes can leak air as well, which you can easily plug with caulk.

Add Ventilation

Another major step to prevent mold growth in your attic is to make sure you have enough ventilation. Passive ventilation methods helps prevent humid air from getting trapped in your attic and wreaking havoc with mold growth.

With that being said, passive ventilation systems may not be enough. Homeowners should consider adding active ventilation, such as an attic fan, to provide continuous airflow. This will help remove hot humid air that enters your attic throughout the year.

Summary

Removing mold from your attic plywood is a step towards a cleaner, safer, and more energy-efficient home. When dealing with serious mold problems, bring in a professional indoor air quality (IAQ) consultant or mold remediation contractors. 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 more healthy and energy-efficient.