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Improving Attic Ventilation

Improving attic ventilation begins with balanced and distributed airflow in your attic space. This is crucial for combatting moisture and heat buildup.

Attics often have variations in temperature and humidity throughout the space. This may occur in high and low points, additions that created new compartments, or unique attic designs that created splits within the attic. Many people don’t realize that the variation in temperature and humidity can be the difference between no problem and major issues. In order to prevent moisture and heat buildup, it is critical to have proper ventilation evenly distributed and balanced throughout the attic. 

ATMOX Graphic - Distributed and blanked Airflow in an attic

Proper Airflow For Ventilation

There are two types of ventilation: passive and active. Passive ventilation is open intake and exhaust points without any mechanical assistance. However, this type of ventilation may not turn over the air efficiently enough to effectively decrease moisture in your attic. Additionally, passive ventilation requires a significant amount of soffits and an extensive ridge vent for adequate ventilation. Active ventilation is the use of mechanical assistance to ventilate air. Therefore, the active ventilation rate of air exchange turns over much quicker with mechanical assistance and improves attic ventilation. This movement is important to prevent moisture and heat buildup. However, air should be pulled through intake points and not the living space. 

Balanced Airflow

ATMOX Graphic of Attic Ventilation

Proper attic ventilation helps combat and reduce moisture and heat in the attic. Key steps include: seal, insulate and ventilate.

Ventilation in your attic must include sealing off your living space from your attic space. This barrier is necessary to protect the attic from the warm moist air seeping in from your living space. Furthermore, there must be enough intake points to pull air from the outside and prevent pulling air from the living space.

The intake air may come from soffits or gables. If soffits are present, check to ensure insulation is not blocking them. This is a common oversight when upgrading insulation or adding spray foam. Additionally, many attics have one large attic fan which can be overpowering and pull air from the living space into the attic. Ventilation should be using air from the outside not your living space. The goal is to reduce the heat but definitely not by using the air conditioning within the house. That defeats the whole purpose of reducing heat in the attic to reduce energy usage of the HVAC system. Airflow must be balanced. In other words, the exhaust pull cannot exceed the ability to draw air in from the outside.

Distributed Airflow

Photo of stained roof decking with mold

A mold problem may arise anywhere there is moisture buildup. In an attic without evenly distributed air, the mold or moisture issue may be localized. Have you ever seen condensation or frost on your roof decking? The condensation or frost is often present only in one area of your roof decking. The presence of this moisture and lack of airflow to this area must be addressed. Evenly distributed air throughout the attic reduces the stagnant air, balances the temperature, and decreases moisture buildup.

Ideally, the attic has the same temperature and humidity across the entire space. However, this is not always the case. If one side gets direct sunlight and the other is in the shade, the temperature differential can be staggering. If air is not evenly distributed throughout the space, there can be pockets or sometimes larger areas of moisture buildup. Distributing the air is critical. You cannot achieve proper ventilation without reaching all areas of the attic to prevent moisture and heat buildup.

The best option is to use multiple fans spread across the attic to keep from pulling from the living space and ensure distributed and balanced airflow. A single oversized attic fan pulls air from the closest location leaving other areas vulnerable to moisture buildup. Multiple fans will prevent from pulling air from one location. Furthermore, this setup will increase air circulation to evenly distribute air temperature and drying ability.

Attic Construction

Homes come is all shapes and sizes. Specifically, some attics have compartments or sections that are blocked from airflow. Other attics, have high and low points that are vulnerable to moisture issues. These variations of shapes and sizes in the attic can pose similar issues with temperatures and humidity varying. Specifically, these compartmentalized or blocked areas within the attic may be more prone to moisture and heat buildup where air is stagnant. Move air in and out of these sections to address the moisture buildup to improve your attic ventilation.

Ventilation of the attic must be distributed evenly to dry and reduce heat. A large attic fan pulls the air from the most immediate source leaving areas of the attic without air movement. Additionally, many attic fans are overpowered and can pull air from the living space. This is not energy efficient and leaves sections of the attic vulnerable to moisture and heat related issues

Photo of ATMOX Pipe fan in Attic with Ducting

Attic Moisture

Moisture issues in any part of your attic can lead to potential problems. When there is moisture present, a mold issue can quickly develop. Prevent moisture issues from becoming major headaches by inspecting your attic for signs of moisture. Fortunately, moisture problems are relatively easy to spot in an attic. However, moisture problems can arise in one section of an attic but not the other so you must check your entire attic space.

Photo of condensation in an attic
Photo of mold on attic sheathing

The cause of mold or wood rot in your attic is moisture. If you have visible mold growth, the CDC recommends that you remove it and take steps to prevent future mold growth. However, addressing only the mold is not enough. Improving attic ventilation will address your attic moisture to prevent further mold growth and other moisture related problems.

Attic Heat

Why should you care about attic heat? Attic heat is not energy efficient and can lead to issues within your home. Mechanical equipment housed in your attic is at risk for damage. Additionally, attic heat increases the heat of your home’s structure therefore increasing the temperatures within the living space. This heat increases the use of your air conditioning and thus energy consumption. This overuse of the air conditioning can overtax your AC system. The heat can create issues and damage to the roof as well. Asphalt shingles will deteriorate in extreme heat from the sun but also from excessive heat generated within the home.

Optimized Attic Ventilation

In order to improve your attic ventilation, you must ensure that you address all areas of your attic. Tackle your heat and moisture with evenly spread fans across the attic space for improving attic ventilation and energy efficiency. Be sure to get air movement to all corners and sections. Contact us for more information on your attic needs.

Post Author: ATMOX TOM