What to Consider while Selecting the right Dehumidifier?

When it comes to determining the right size of the crawl space dehumidifier, square footage is just a number. Several site-specific factors affect how much moisture your crawl space dehumidifier needs to remove daily. Therefore, there are several aspects that you must consider while choosing the size. Let’s dive deep into it.

• The Size of Your Crawl Space

Square footage is where you begin. Take the length and width of your crawl space to measure the square footage and use it as a baseline. A large area means more room for the moisture to build up, which automatically requires more dehumidification capacity. Additionally, you cannot ignore the odd-shaped crawl spaces or the ones with multiple sections, as these areas can prove to be dead zones, making you lose all your dehumidification investments.

• Moisture severity level of the crawl space

The moisture severity level of your crawl space helps you pick the right dehumidification approach. A crawl space with 80% relative humidity level requires a different dehumidification capacity in the same square footage. The dehumidification requirement for a crawl space with 60% relative humidity level is different. However, you can assess if the moisture level in your crawl space is mild, moderate, or severe using a general rule of thumb.

Mild (55–65% RH): A crawl space with a mild moisture severity level has no visible structural damage, but a foul smell. The relative humidity here usually ranges between 55-65% RH, and this is where the standard sizing works fine.

Moderate (65–75% RH): A crawl space with a moderate moisture severity level feels damp with slightly visible mold spots and condensation on the pipes. The relative humidity here usually ranges between 65-75% RH. It is recommended to add a 10–20% cushion of capacity to the actual dehumidification capacity that your square footage requires.

Severe Level (75%+ RH): A crawl space with a severe moisture severity level has heavy mold, standing water, seepage, or wet soil. Here, the relative humidity is usually greater than 75% RH. In this case, it is recommended to size up significantly and tackle the source of moisture as soon as possible.

• Special conditions of your crawl space

You must look beyond square footage merely if your industrial or commercial crawl space has moisture-amplifying conditions. The conditions that boost the moisture load significantly include water intrusion or past flooding, high groundwater level, exposed plumbing, and soil or dirt on the floor. Or the presence of any heat-producing HVAC equipment that adds more humidity to an already humid atmosphere. If any of these factors are at play, you must size up rather than relying on the baseline dehumidification capacity.

• Ceiling Height and Total air volume

Some industrial crawl spaces have low ceiling heights, and others have taller ones, causing more air volume for dehumidification. A crawl space with 4 feet ceiling height has twice the air volume of one with a 2-foot ceiling height. Higher air volume means more moisture-laden air to dehumidify. You must look for cubic footage while selecting a dehumidifier if your crawl space is taller than usual. Multiply the ceiling height by the square footage to get the cubic feet. 

• Climate Zone and Seasonal humidity level

The industrial and commercial crawl spaces in the southern regions or humid coastal areas usually face higher levels of moisture. Northern climates may see moisture spikes in summer. Cold winters also leave an impact on the regular performance of a crawl space dehumidifier. It is recommended to go for an aggressive baseline sizing if your business is located in a high humidity climate zone.

• Design of The crawl space

The physical layout of your commercial crawl space directly affects the airflow and moisture concentration. If your crawl space is open-vented, it invites more outside air, which results in more air to process and more workload for your dehumidifier. Similarly, if your crawl space has several access points, it brings in the air from the outside. If the crawl space is segmented or L-shaped, you will need more than one dehumidifier unit to maintain the right humidity levels. However, if your crawl space is encapsulated, the moisture is trapped in. The excessive moisture in the indoor environment is manageable, and the dehumidifier size becomes more predictable. 

• Presence and Condition of a vapor barrier

A rightly installed vapor barrier helps reduce the moisture load significantly. It’s the one that comes with a 12 to 20 mil polyethylene covering the entire floor and sealed at the walls. If the vapor barriers are well placed and in good shape, you can go for dehumidifiers with less dehumidification capacity. However, if it is missing or not intact, you will need to size up.

What Size Dehumidifier Do You Need for a Crawl Space?

Industrial and commercial crawl spaces’ dehumidifiers are required to be more robust than usual. These units come with features including condensate pumps, low-temperature performance, and durable construction. Here are some guidelines based on common dehumidifier sizing recommendations for commercial and industrial crawl spaces. The recommended dehumidification capacity for various square footage of commercial and industrial crawl spaces is as follows: