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Does My Crawl Space Need a Dehumidifier?

In Richmond, summer humidity can be brutal. But while you may be comfortable in the AC, that out-of-sight, out-of-mind crawl space below is definitely feeling the heat.

That’s why most people are surprised to discover a problem in their crawl space, because it’s often a forgotten part of their home, but it shouldn’t be. For most homes, up to 60% of the air in it comes from the crawl space, and when it becomes humid and damp, it quickly becomes a problem.

At Kefficient, one of the most common questions we’re asked about crawl spaces has to do with dehumidifiers and whether every crawl space needs one. The short answer is yes because, without one, the risk of your crawl space developing issues like wood rot and mold increases dramatically – even if the crawl space is encapsulated!

What Do Crawl Space Dehumidifiers Actually Do?

A crawl space dehumidifier is a device that reduces the humidity levels in the crawl space. It works by drawing in moist air and removing the excess moisture, typically through condensation. By controlling the humidity levels, crawl space dehumidifiers improve indoor air quality, reduce the risk of mold growth, and prevent structural damage.

Installing a crawl space dehumidifier also provides additional benefits:

  • Lower Electric Bill: High humidity levels make your air conditioning system work harder to cool your home, leading to higher utility bills.
  • Extended HVAC Lifespan: A crawl space dehumidifier can also improve the lifespan of your HVAC system by reducing the workload and leading to fewer breakdowns.
  • Improved Indoor Air Quality: Controlling the humidity levels in your crawl space can also prevent musty odors, making your home more comfortable and pleasant.

What Are The Signs That My Crawl Space Needs a Dehumidifier?

The signs your crawl space needs a dehumidifier can be subtle but become unmistakable. These include musty odors, condensation on pipes and fixtures, and mold growth. Exposure to mold spores can cause respiratory issues, such as allergies, asthma, and other health problems. High humidity levels, combined with Richmond’s summer heat, can also cause wood rot and cause the floor above your crawl space to sag, commonly described as cupping floors.

If you notice any of these signs, it’s important to act sooner rather than later. If caught in time, installing a crawl space dehumidifier can remove excess moisture, improve indoor air quality, and prevent mold growth and health issues caused by mold exposure.

How Do I Select The Right Dehumidifier For My Home?


When selecting a crawl space dehumidifier, there’s a lot to consider. For starters, knowing the size of your crawl space is crucial in determining the right size of the unit. If your crawl space is large, you will need a dehumidifier with a higher capacity. The energy efficiency of the dehumidifier is also essential in reducing energy consumption and saving on utility bills.

In addition to understanding size, you must understand what RH level to set your dehumidifier. An RH level is a term for relative humidity, and it measures the moisture in the air of your crawl space. For most homes in Richmond, keeping your crawl space between 40-60% will create a dry environment for your crawl space. RH levels above 60% increase the humidity, causing wood rot and mold. However, if the RH level is too low, it can dry out the crawl space completely, leading to your wooden floor joists and beams cracking and causing structural damage.

The best way to think about it is like Goldilocks and the three bears – too hot, too cold, just right.

How Do I Install A Dehumidifier In My Crawl Space?

Installing a crawl space dehumidifier yourself without the right tools or level of expertise can be difficult for any homeowner. Most units need a dedicated power supply and adequate drainage to work at their peak efficiency. Determining what dehumidifier would work best in your crawl space can also be hard – but that is where we can help.

At Kefficient, our experts in Richmond can provide a free crawl space inspection offering helpful advice on what it needs to be safe from high humidity, wood rot, and mold. In addition, we can also provide hassle-free installation of an energy-efficient dehumidifier with an industry-leading warranty so that you can breathe easily.