Crawl Space Dehumidifier Installation and Noise Mitigation

By: Evan Scoboria, Last updated: June 27, 2023

Dehumidifiers are essential for maintaining a healthy and moisture-free crawl space, preventing mold growth, and improving indoor air quality. Proper installation is crucial for ensuring your dehumidifier operates effectively and efficiently. In this step-by-step guide, we'll cover the process of installing a crawl space dehumidifier, including a noise and vibration mitigation section, by suspending the unit from floor joists using rubber straps.

Santa-Fe Dehumidifier Installed In Crawlspace

Assessing Your Crawl Space

Before installing a dehumidifier, inspect your crawl space for moisture issues and ventilation needs. Check for signs of water leaks, mold growth, and inadequate vapor barriers, and address these issues before installation.

If possible, cover all bare soil with a plastic membrane entirely. This membrane can be as simple as the inexpensive black plastic you'll find at any construction supply store, or you can spend a little more to purchase a clean white plastic membrane infused with fibers to make it stronger and more durable. You'll want to apply a double-wide layer of duck tape at every joint, ensuring moisture can not work through the barrier. Then use butyl tape to adhere the membrane as high up your foundation surface. 

Inspect your crawl space for a location to route the wastewater produced by the dehumidifier. In some installations, water can be drained through a hose into a floor or French drain that leads out of the home. These installations can be successful, but I prefer to route wastewater directly into the sewer system when allowed by municipal code. You'll want to select a location in your crawlspace with easy access to a cleanout or sewer pipe termination. 

Finally, consider what rooms are located above your crawlspace. It's usually best to put a dehumidifier under a daytime-use room like a kitchen or bathroom rather than a bedroom where even small vibration levels can cause disruption. 

Choosing the Right Dehumidifier

Select a dehumidifier suitable for your crawl space's size and humidity levels. Consider pint capacity, energy efficiency, and drainage options when choosing your unit.

In most crawl space installations, I choose a durable commercial unit like the Santa Fe Compact70 or Santa Fe Compact 2. These units are worth every penny and can run for years with only minor maintenance while removing as much at 60-70 pints of moisture per 24-hour period.  

Alternatively, you can look for a lower-cost unit at Home Depot or Lowes. Select one with enough PPD capacity to meet your needs and, ideally, installable in a suspended position. 

Preparing for Installation

Preparing for the installation of your dehumidifier is a crucial step. Here are some factors to consider and steps to take:

Gather Necessary Tools and Materials: Before you begin the installation, please ensure you have all the tools and materials ready. These may include:

Access to Power Source: You'll need a power source nearby to plug in the dehumidifier. Please ensure that the power source is reliable and can handle the electrical load of the dehumidifier. You will need a suitable extension cord if the nearest outlet is far away. Remember, ensuring all electrical connections are safe and dry is crucial.

Drainage Solution: The dehumidifier will collect water from the air, so you'll need a way to drain this water. Some units come with a collection bucket you'll need to empty regularly. However, a continuous drainage solution is more convenient in a crawl space. This could be a floor drain or a condensate pump that can pump the water to a suitable drainage location.

Plan for Noise and Vibration Mitigation: If you're planning to suspend the dehumidifier from the floor joists for noise and vibration mitigation, you'll need rubber straps and mounting hardware. Consider the unit's weight and get straps and hardware that are strong enough to hold it securely.

Assess the Installation Area: Examine where you plan to install the dehumidifier. Ensure the surface is level and sturdy enough to hold the unit if you're not suspending it. Check that there's enough space around the unit for proper airflow, which is essential for the dehumidifier to work effectively.

Preparing correctly for installation will help ensure the process goes smoothly and that your dehumidifier operates efficiently and effectively.

Installing the Dehumidifier In Standing Position

If you're planning to install your dehumidifier in a standing position in your crawl space, here are the steps you'll need to follow:

1. Choose the Location: First, select a suitable location within the crawl space. The dehumidifier should be placed centrally to reduce moisture levels throughout the space. Also, ensure the selected area has a flat and level surface to keep the dehumidifier stable.

2. Position the Dehumidifier: Place the dehumidifier on the chosen spot. Ensure adequate space around the unit for proper airflow, which is essential for the dehumidifier to function effectively. Any debris or insulation should not obstruct the unit.

3. Power Connection: Connect the dehumidifier to a power source. Check the manufacturer's instructions for any specific guidelines regarding power connections. Always ensure that power connections are dry and safe to prevent electrical accidents.

4. Set Up Drainage: Your dehumidifier will collect water from the air, which needs to be drained. Attach a drain hose to the unit and ensure it leads to a suitable drainage point. If your dehumidifier comes with a condensate pump, connect it per the manufacturer's instructions. This will allow the water to be pumped out to a suitable drainage location, even if it's some distance away or uphill from the dehumidifier.

5. Adjust Settings: Finally, adjust the settings on the dehumidifier according to the manufacturer's recommendations and your specific needs. This will typically involve setting the desired humidity level, and most manufacturers recommend a relative humidity level of less than 50% to prevent mold growth and other moisture-related problems.

Noise and Vibration Mitigation with Suspended Installation

Suspending the dehumidifier from the floor joists in your crawl space can significantly reduce noise and vibration and also helps protect the unit from potential flooding. Here is how you can achieve this:

1. Measure the Distance: Start by measuring the distance between the floor joists where you plan to hang the dehumidifier. This will show you how long your straps need to be.

2. Prepare the Rubber Straps: Cut rubber straps to the appropriate length, and attach the mounting hardware to the ends of each strap. These straps will be used to suspend the dehumidifier from the joists.

3. Attach Straps to Joists: Securely attach the rubber straps to the floor joists using the mounting hardware, ensuring they are level and evenly spaced. Ensure the straps are securely fastened and can bear the weight of the dehumidifier.

4. Suspend the Dehumidifier: Carefully lift it and attach it to the rubber straps. The dehumidifier should hang securely from the straps. Make sure the unit remains level and secure. An unlevel unit may not operate properly and could also lead to unnecessary stress on the straps or the dehumidifier's casing.

5. Check the Installation: Double-check everything once the dehumidifier is suspended. Ensure the straps are secure, the unit is level, and there is proper clearance for airflow around the dehumidifier.

This suspended installation method helps with noise and vibration mitigation, protecting the unit from ground moisture or potential water intrusion in the crawl space. Regular maintenance, such as cleaning or replacing filters and checking the unit for wear or damage, is still essential, even with a suspended installation.


Installing a crawl space dehumidifier is critical in maintaining a healthy and moisture-free environment in your home. Following this step-by-step guide, you can ensure your dehumidifier is installed correctly, mitigating noise and vibrations by suspending the unit from floor joists with rubber straps. With the proper installation and regular maintenance, your dehumidifier will effectively manage moisture levels in your crawl space and improve indoor air quality.