High moisture levels can result in physical discomfort, increased air conditioning costs, and possibly serious health issues. In addition, damage to your home and your home's furnishings can result. Maintaining relative humidity below 50% prevents dust mite infestations, mold and mildew growth, and inhibits the growth of bacteria. Lower relative humidity also reduces the out-gassing of volatile organic compounds – creating a healthier environment in which to live and breathe for you and your family.
Dust mites and mold are the two most common allergens present in higher humidity environments. These allergens do not require water to grow – they only require humidity levels at or above 65% to 99% at the surface on which they grow.
Dust mites live in upholstered furniture, carpets, and mattresses. They absorb their moisture needs from the air. If the relative humidity is below 50%, according to Dr. Larry Arlien at Wright State University, dust mite infestations will be eliminated.
Molds are fungi. They only require high humidity and an organic-based material on which to feed. It is no surprise that they are plentiful in humid environments. Cooler surfaces create a perfect breeding area for mold because the relative humidity at the surface will be near 100%. The surface may even be wet with condensation.
Mold growth can be eliminated in the home through humidity control that maintains reduced relative humidity levels and prevents cooler surfaces from becoming damp. To avoid the problems caused by moisture, and to create a comfortable environment, a dehumidifier is necessary to maintain relative humidity between 45-50% throughout the home. Keeping your relative humidity at 50% or less eliminates mold, mildew and dust mites.
Basements are naturally cooler than the rest of the house, which makes them subject to high humidity. Because the basement floors and walls are in contact with the soil, and soil temperatures several feet below the surface remain at a constant temperature of 50°-60°F or less, basement floors and walls tend to remain cool. Also, basements generally do not have windows and so there is no solar heat gain. Therefore, since basements tend to be cool and cool air holds less moisture than warm air, basements will have higher relative humidity.
Moisture is the most common problem in basements—either entering from outside sources or being produced inside by the occupants' activities. The soil around the walls can contain a large amount of moisture from surface water that is seeping down or from a high water table. Water can find its way inside by gravity or through a crack or flaw in the water protection layer of the foundation. Water can also be pulled up by a "wicking action" or "pushed up" by hydrostatic pressure from the soil under the walls or floor.
Excess moisture, introduced by way of unsealed, vented crawlspaces, contributes to wood rot, mold growth and increased pest activity. Moisture in crawlspaces often migrates to the upper levels of the home through a "stack effect." In essence, whatever air is below the house is also in the house. As warm air rises and escapes through the upper levels of the home, new air finds its way into the home to replace what's been lost. Intake air comes in at the lower levels – through unsealed crawlspaces. This may lead to costly problems such as cupping of hardwood floors, mold growth, increased air conditioner loads, and swelling of millwork/cabinetry. Air infiltration from the crawlspace often carries odors and may contribute to poor indoor air quality and uncomfortable humidity levels.
Excess moisture in crawlspaces has also been associated with contributing to increased energy consumption. Wintertime ventilation cools the crawlspace contributing to heat loss from the home. In the summer, introducing warm outside air under the home contributes to heat gains, increasing cooling loads. Ventilation of a crawlspace to control relative humidity only works consistently in an arid climate. In most climates, ventilation can actually add significant quantities of moisture during humid times.
Venting a crawlspace will either add moisture to, or remove moisture from, a crawlspace depending on the moisture content of the ventilation air compared to the desired conditions of the crawlspace. Venting with dry air reduces moisture levels in the space, while venting with moist air contributes moisture. It is false to assume that venting will automatically bring in "good" air and push out the "bad" air. If the outside air is humid and the crawlspace air is humid, you're not making any improvements by venting. Since venting either wets or dries the space depending on outside conditions, there is no way to guarantee a specific moisture level in a vented crawlspace.
The solution to this dilemma is to close the crawlspace. One of the objectives of closing crawlspaces is to reduce sources of moisture entering the space. Even when done meticulously, closing a crawlspace will significantly reduce the moisture but not eliminate it. Active conditioning of the space may be necessary to maintain proper humidity levels. A dehumidifier can provide long-term, active moisture control and ensure humidity levels are maintained at a specific level which is adjustable by the home's occupant.
It is important to note the areas of concern when taking steps to responsibly convert your vented crawlspace to a sealed and conditioned space. Those include, but are not limited to: assuring proper water drainage, installing vapor barriers, consideration for combustion and carbon monoxide and sealing outside vents and controlling moisture.
The best way to combat the problem of humidity migrating through the roof, walls, and floor is to pressurize the building with dehumidified air. This strategy involves bringing a measured amount of outdoor air into the structure and dehumidifying it before it enters the living areas. An equal amount of drier indoor air will escape from the structure to equalize the pressure. This ventilation strategy, provided by the Ultra-Aire system, prevents humid outdoor air from infiltrating the structure and offers the ventilation recommended by health experts. The Ultra-Aire has been incorporated into numerous American Lung Association Health Houses and is your best solution to solving indoor air quality issues which includes filtration and dehumidification for increased indoor air quality.
Santa Fe dehumidifiers will help maintain the structural integrity of your home, inhibit mold growth, and improve the indoor air quality of your home by removing odor-causing moisture. This dehumidifier line will also maintain 50% or less relative humidity as recommended by the EPA, American Lung Association, and American Medical Association. Santa Fe dehumidifiers are designed to control humidity even in the cooler environments of basements and crawlspaces.