Do Crawlspace Fans Actually Work?

crawlspace fan

Many homeowners turn to crawlspace fans in an attempt to address humidity problems. Are they effective, though? Today, we’re going to cover this topic in detail. 

The Problem with Crawlspace Fans

Crawlspace fans require crawlspace vents to function. The fan is pointed into the crawlspace to circulate outside air. In theory, cycling the air can prevent moisture and reduce humidity. 

However, crawlspace fans are mostly pumping in warm air from outside. Crawlspaces require crisp, cool, and dry air to maintain an optimal environment. While you may reduce moisture levels with a fan, you are not eliminating it. Instead, this creates an environment where mold and mildew can still build up. 

Mold, mildew, and fungi that accumulate in your crawlspace can cause structural damage. This impacts the safety of your home and creates more expensive remediation challenges in the future. 

Lastly, crawlspace fans require an opening. This can invite insects, rodents, and other pests into your crawlspace and create additional problems. 

How Does Moisture Enter My Crawlspace in the First Place? 

Water can enter your crawlspace in a variety of ways. These can include, but aren’t limited to: 

  • Water entering penetrations in the foundation wall 
  • Hydrostatic pressure affecting the foundation wall
  • Open foundation vents or windows that condense on cool surfaces 
  • Moisture evaporation from the soil floor in the presence of warmer air 
  • Defective plumbing and/or HVAC systems 

The cause of the moisture will help determine the best solution for your crawlspace. The goal would be to correct the existing issue and prevent similar ones from reoccurring in the future. 

Alternatives to Crawlspace Fans

We believe that each home deserves a customized solution. Sometimes, this involves multiple pieces of equipment working in tandem. 

Some alternatives to crawlspace fans that we recommend include: 


Waterproofing combines multiple solutions to prevent moisture from entering your crawlspace. This approach will often involve more than one piece of equipment. This can include drainage systems, dehumidifiers, and other similar features. 

Crawlspace Encapsulation 

Only dirt floor crawlspaces require encapsulation. Because there is no barrier between the ground and the crawlspace itself, the moisture intrusion can increase humidity levels. During this process, the floor and foundation walls are covered with a strong vapor barrier. 

Most basic vapor barriers are made from polyethylene and are about 4 millimeters thick. While these are designed to be waterproof, they may not prove sufficient for your needs. We recommend a multi-layer vapor barrier that is extrusion laminated and scrim-reinforced. 

There are also more advanced vapor barriers on the market that offer additional features. These can include fire-retardant materials, increased thickness, and other protective attributes. 

Most encapsulation materials are sturdy and durable. If you notice tears in the vapor barrier, you should contact a professional as soon as possible to correct the issue. Leaving the vapor barrier compromised will create an opening for new moisture damage. 

The encapsulation process typically takes one day for most properties.

Crawlspace Drainage Systems 

A custom crawlspace drainage system will help stop moisture accumulation permanently. It helps remove water and dirt to defend against mold and rot damage. 

Some crawlspace drainage systems a professional might recommend include: 

Sump Pump

Sump pumps are usually suggested when a large amount of standing water is present in your crawlspace. They offer an effective, low-cost solution and allow you to remove large amounts of water quickly. They are often recommended for homes with HVAC systems and other vulnerable appliances in the crawlspace. 

French Drains

French drains direct water away from your crawlspace or basement. They provide a convenient and passive solution for homeowners and are a common solution for customers with groundwater penetration issues. 

Costs for Crawlspace Moisture Protection 

If you are considering a crawlspace moisture protection system, you are probably concerned about cost. We completely understand. You’re investing in the long-term health of your home. 

The best way to obtain an estimated cost would be to contact a local professional. They will pay a visit to your property, examine your crawlspace, and provide an estimate. Each crawlspace is different, so a completely customized solution proves the best option. 

If you cannot pay the full cost upfront, be sure to ask your service provider about financing options. For example, we partner with GreenSky to offer to finance to our own customers. 

Looking for an Alternative to Crawlspace Fans in Maryland? Let Us Help 

Protecting your crawlspace is an investment in the long-term health of your home. Preventing future mold and rot damage will also help you avoid more costly repairs in the future. 

Since 2006, we have helped our neighbors in Salisbury, MD, and the surrounding areas better protect their crawlspaces from the risk of moisture damage. If you are interested in a free estimation, please contact us anytime and our team will be schedule an appointment to visit your property.