Crawl Space Dehumidifiers, Crawl Space Fans by Pioneer Home Services NW in Portland OR

Moisture in a crawl space should never be taken lightly. Damages from moisture can wreak havoc on the stability of the structure. Mold, mildew and other fungi thrive in these dark, damp areas resulting in unsightly, smelly and unhealthy conditions. So, to keep these problems under control, it is crucial to keep the moisture under control.

Evolution of Crawl Spaces

Homes have not always been built with crawl spaces. As the “modern” home evolved in the pre- and post-World War II era and indoor plumbing became a common inclusion in home construction, the crawl space became a means by which plumbing, ventilation, ductwork, etc. could be accessed for repairs and maintenance. The crawl space also served as a means for increased air circulation for the home.

In the early 1940’s many homes did not have an enclosed crawl space. As time and building codes progressed, crawl spaces became enclosed areas. To keep the fresh air moving, these enclosed spaces were constructed with vents. Typically, residents would open the vents in the spring and keep them open until the end of the summer, when the vents would be closed.

As time progressed to the 1970’s, homes began adding central air conditioning which began the matter of crawl space moisture problems. These artificial cooling systems pulled hot air from the outside to cool. Because hot air contains more moisture than cool air, the humid air brought moisture into these crawl spaces, along with condensation from the cooling of the air by the air conditioning units.

Solution to Moisture Control

As contractors and homeowners became aware that their crawl spaces were becoming damp, they began to try to resolve the problem initially with the installation of crawl space fans. And, as is a common rule of thought, they figured that if one or two fans were good, then five crawl space fans would serve even better. The results were not always good. Some homes saw improvement while the moisture in others actually worsened.

Another solution is that of the use of crawl space dehumidifiers. Crawl space dehumidifiers require a sealed crawl space, but they are very efficient and bring several advantages over the use of crawl space fans for moisture control.

Advantages and Disadvantages of Dehumidifiers


  • Energy efficiency: dehumidifiers typically use a very small amount of electricity.
  • Greater overall energy savings due to the fact that dry air can be easier tolerated at warmer temperatures than humid warm air.
  • Easy and low-cost maintenance: a dehumidifier only requires an annual maintenance inspection.
  • Improved appearance of crawl space due to encapsulation required for the dehumidifier.
  • May add market value to the home.


  • Preparation and sealing the crawl space may be expensive.
  • The preparation of the crawl space and the installation of the dehumidifier must be carried out properly in order to maintain termite warranties and allow for inspection.

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Advantages and Disadvantages of Fans


  • Less costly to purchase and install
  • Fairly inexpensive to operate on a daily basis


  • Can draw too much humid, warm air into the crawl space, worsening the problem
  • Can be an electrical fire hazard
  • Noisy operation
  • Usually do not last long, needing frequent replacement
  • Multiple fans are often needed to achieve velocity

Moisture in a Crawl Space

Crawl space moisture is a problem that cannot go unchecked indefinitely. Whether a system of fans or a dehumidifier is used to rectify the problem, it is important to assess all of the pros and cons to make the best decision for the matter at hand.

If unsure as to which option is the best, it is always a good idea to call in a professional home service with representatives who are trained in dealing with this type of problem for advice.

Crawl Space Dehumidifiers in Portland OR and Vancouver WA

Serving Clients in the Greater Portland OR Area:
Portland OR | Gresham Oregon | Troutdale | Sandy | Boring | Clackamas | Happy Valley | Milwaukie | Gladstone

Oregon City | West Linn | Lake Oswego | Tualatin | Tigard | Beaverton | Aloha | Hillsboro | SE Portland | NE Portland | SW Portland

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