ATMOX Attic Fans

There are two main reasons to add attic fans to your home:

MOISTURE CONTROL & HEAT REDUCTION

ATMOX icon for crawlspace and attic moisture control
ATMOX ico for attic heat reduction

ATMOX fans are the tool to exchange and circulate the air in the attic. The concept behind any fan is really very simple. Remove the hot and/or wet air and replace it with drier fresh air.

Key considerations for using fans in a attic:

  • Outside air needs to be drier than inside air in order to reduce moisture.
  • The excessively hot air in the attic needs to exchanged fairly quickly to reduce the temperatures in the attic.
  • The airflow should be balanced and spread out across the attic. This is especially important in tackling moisture.
  • The attic needs intake air from soffits or other openings. Air will not properly pull from the outside if the attic has insufficient or blocked intake points.

For optimal performance in heat and moisture reduction, you need the ATMOX APEX Controller to determine exactly when the fans should be in operation. Contact ATMOX or work with your installer to determine the best options for your home.

Fan Models for Attics

Different parts of the country have different construction styles for roofs and attics. For this reason, ATMOX fans have various mounting options to adapt to various openings: Gable, Ridge Vent or Roof. Learn more about what is typical for your geographic area in the ATMOXsphere sections.

Your installer will determine the exact needs for your attic.

Frequently Asked Questions About Fans in the Attic

What is an attic fan?

An attic fan draws air from inside the attic and expels it to the outside. These fans come in a variety of styles, and different models will be mounted in different ways. In warmer climates, the goal is generally to reduce heat. In colder climates, heat may be less of an issue, and the fan will be installed to reduce moisture levels in the attic.
Attic fans are sometimes confused with whole-house fans. These fans have a different purpose. This style of fan cools the house by pulling air from open windows through the house and into the attic. In select climates, these fans can reduce the temperature in the house on a cool summer night as an alternative to air conditioning. This is different than an attic fan, since the air is blowing into the attic. Whole-house fans serve a completely different purpose.

How do attic fans work?

Attic fans work to reduce heat or moisture within the attic. The fans create active ventilation for the attic. Many attics suffer from insufficient ventilation particularly from passive movement from gable to gable or from soffit to ridge vent. If the air isn’t moving quickly enough, then the heat or moisture builds up. The air has to move quickly in order to be effective. When using attic fans, the first step is to properly seal any gaps or openings on the attic floor. Then, the next step is to insulate properly to limit temperature transfer between spaces. Finally, ventilate the attic. The attic fans pull the outside cooler and drier air into the attic and push the hotter and more humid air out.

Do attic fans really help to reduce heat?

Yes! Attic fans will reduce heat in the attic. Attics can easily reach over 150 degrees in peak summer time without enough ventilation. Obviously, that’s hot! The fans will exchange the air with the cooler air from the outside. Even if it’s 90 degrees outside, that is still significantly lower than the extreme temperature within an attic. The goal is to keep the air moving so that it has less time to be heated by the solar energy coming through the roof deck.

Do attic fans really work to reduce moisture?

Yes! Attic fans exchange the air in the attic. In most homes, heat and moisture from within the house travel upwards and end up in the attic. Consequently, the moisture sometimes gets trapped. This can become a major problem if the humid air starts hitting cold surfaces creating condensation. That water leads to the potential for mold and wood rot.
The fans keep the air moving in the attic. As you exchange the air, the fans push out the moisture in that air as well as replace the air with fresh air from the outside. Winter air tends to be very cold and dry. An ATMOX attic controller ensures that the air outside is beneficial to the attic before activating fans.

How many attic fans do I need?

Fans needed is determined by the size of the attic and the power of the fan. ATMOX generally recommends that the attic air cycles approximately six times per hour when the fans are operating. Calculate the cubic feet within your attic to find the size. Fans are rated by CFM which stands for Cubic Feet per Minute. A typical attic may use four ATMOX Attic Exhaust Fans at 225 CFM each to balance and distribute the airflow.
Other fans on the market may have a much higher CFM, so you may need fewer of those. However, it is is important not to overpower the attic ventilation. One, it can be energy inefficient and use a lot of electricity. Two, if you don’t have enough intake points for air to come in, then the fans may start pulling air from within the living space. More is not always better.

Attic Fan Power and Electricity Usage

The ATMOX fans use low voltage electricity which means the fans can receive power with a low voltage wire (often used in landscape lighting). In general, the ATMOX Controller provides the power source for all of the fans from one electrical outlet. In most cases, the fans connect to wire without the need for individual electrical outlets and without an electrician. Each fan attaches onto the low voltage wire to receive power and generally the command for operation.

Separately, an AC adapter can power a fan directly from an electrical outlet without a controller or low voltage power supply.

All ATMOX fans are extremely energy efficient, so they can run frequently without concern of energy usage. Each fan only uses 15 watts of power when running. Comparatively, other models on the market use significantly more power. It can be a huge difference.