ATMOX Crawl Space Fans

ATMOX fans reduce moisture in the crawlspace and improve air quality. The concept behind any fan is really very simple. Remove the damp or stale air and replace it with drier fresh air. Fan usage is common throughout our homes to move moisture. Just think about the range hood in your kitchen or the exhaust fan in your bathroom. The fans are exchanging the air in your house. Crawl space fans are doing exactly the same thing inside the crawl space.

Key considerations for using fans in a crawl space:

  • Outside air needs to be drier than inside air in order to reduce moisture.
  • Outside air should be in an acceptable temperature range to avoid extreme temperatures, especially freezing cold air that could cause pipes to freeze.
  • Fresh healthy air can only be achieved by exchanging the air within the crawl space.

For optimal performance in moisture reduction with crawl space fans, you need the ATMOX ACE Controller to put it all together. Contact ATMOX or work with your installer to determine the best options for your home.

Exhaust and Intake Fan Models

Different parts of the country have different construction styles and geographic climates. For this reason, ATMOX crawl space fans come in different models to adapt to various vent size openings. Learn more about what is typical in your geographic area in the ATMOXsphere sections.

Each model is also designed as either an exhaust fan to push air out of the crawlspace or an intake fan to draw air in from the outside. Intake fans are somewhat unique to ATMOX. The fans serve an important role to keep the airflow balanced within the space. If you only use exhaust fans, there is a possibility of creating too much pressure and actually using make-up air from inside the living space instead of from outside. Your installer will determine the exact fan needs for your crawl space.

Frequently Asked Questions about Crawl Space Fans

Why should I have fans for my the crawl space?

Fans in the crawl space have two primary goals – reduce moisture and improve air quality.

There is a huge misconception that outside air is “bad”. Sure, there are times of year or times of day when outside air can be too cold or too hot or too humid. However, there are many more times throughout the year when outside air is the perfect drying tool. Just look at how mother nature dries itself out with changing atmospheres and weather patterns. The key is knowing when that outside air will be beneficial to drying out the crawl space to reduce moisture – that’s where the ATMOX controller comes in.

Crawl space fans move air! Many crawl spaces are tight and not getting enough ventilation through passive open vents alone. You can’t improve air quality without exchanging the air! There are ways to make air drier or more humid with dehumidifiers or humidifiers, but if there are toxins in the air that won’t change until you exchange the air. For example, this why radon mitigation systems use fans or why you immediately open windows with carbon monoxide detection – you have to exchange the air to improve the air quality.

When should the crawl space fans be running?

Fans should be running when they are beneficial to the crawl space. So, you may be asking yourself, how do I know if the air is beneficial? Outside fresh air will almost always help with air quality concerns, since it is exchanging stale air. However, the other main goal is to reduce moisture. In this case, the fans will have optimal operation when controlled by the ATMOX ACE Controller. The basic operation for using exhaust and intake fans occurs when the outside air is drier than inside. This is determined using a dew point comparison of conditions. The controller is also looking for energy efficient operation of the whole house and will check temperature levels of outside air to make sure that they are in an acceptable range.

How many crawl space fans do I need?

The number of fans needed will depend on the size and layout of the space. A larger or more compartmentalized space may need additional fans to better distribute the airflow. Your installer will determine how many fans to install. You can get an idea of typical setups including number of fans for a 2000 square foot crawl space – just view your region.

Fan power is typically measured by CFM or cubic feet per minute. This tells you how much air a fan can move within a minute of time. Without getting too technical, the goal is generally to exchange the air in the crawl space four to six times per hour when running.

What size crawl space fan do I need?

Most crawl space vent openings are 16 inches wide and 8 inches high. The following models will fit these openings by mounting internally from behind the vent opening: Multi-Mount Fan with Louver (225 CFM) and Internal Mount Fan (220 CFM). The following model will fit an exact opening of this size by mounting externally from outside the crawl space into the opening: External Exhaust Mount Fan.

In certain parts of the country (typically on the West Coast), crawl space vent openings are smaller. The following model is specifically designed to fit in these openings by mounting internally from behind the vent opening: Internal Mount Fan with removable grill (220 CFM).

How are the crawl space fans installed?

Exhaust and intake fans mount in or behind a vent opening to the outside. Most fan models have plates screwed directly to the wall from inside the crawl space. The fans with an attached vent cover install from the outside and tighten with tension screws inside the opening.

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.

The crawl space fans are extremely energy efficient, so they can run frequently without concern of energy usage. The fans only use between 10 to 15 watts of power when running depending on model.

Learn more about related ATMOX Crawl Space Products