Dehumidifiers

Benefits

A whole-house dehumidifier improves IAQ by maintaining a relative humidity level between 30% and 50%, which is the ideal range for health and comfort. 💧 High humidity is a breeding ground for allergens and contaminants such as mold, mildew, and dust mites. By removing excess moisture, a dehumidifier helps to inhibit the growth and spread of these pollutants, which can be particularly beneficial for people with allergies, asthma, or other respiratory conditions. Furthermore, it helps eliminate the musty odors often associated with dampness.

In terms of energy efficiency, a whole-house dehumidifier allows your air conditioner to operate more effectively. Air with a high moisture content feels warmer and stickier. By removing moisture from the air, a dehumidifier makes the home feel cooler at a higher temperature, which means you can set your thermostat a few degrees higher without sacrificing comfort. Since a dehumidifier generally uses less energy than a central air conditioner, this reduced AC usage can lead to noticeable savings on your utility bills.

Sizing for a Property

Sizing a whole-house dehumidifier isn't as simple as just matching it to a home's square footage. While this is a starting point, it's crucial to consider other factors that contribute to the home's moisture load.

1. Square Footage: Dehumidifiers are rated by the number of pints of moisture they can remove per day. A typical whole-house unit for an average-sized home (up to 5,000 square feet) can remove between 80 to 155 pints per day.

2. Climate and Existing Conditions: A home in a hot, humid climate will require a higher-capacity dehumidifier than one in a dry climate. Factors like a damp basement, a crawl space, or a history of water issues also increase the required size.

3. Building Tightness: A new, well-sealed home will have a lower moisture load than an older, leakier home. Professionals often classify a home's air leakage as "loosely sealed," "moderately sealed," or "very tightly sealed" to help with sizing.

Factors for Sizing

1. Home's Square Footage and Volume: The total volume of air in a home is the most basic starting point. A larger home requires a higher-capacity dehumidifier.

2. Climate and Location: A home in a hot, humid climate will have a much higher moisture load from the outside than a home in a dry climate. This is often the largest source of moisture.

3. Building Tightness: The air leakage of a home is a major factor. A "leaky" home that is not well-sealed will pull in more humid outdoor air, requiring a higher-capacity dehumidifier to maintain a comfortable humidity level.

4. Internal Moisture Sources: Activities within the home, such as cooking, showering, and the number of occupants, all add to the moisture load. Basements and crawl spaces, in particular, are significant sources of moisture.

Recommended Sizing

While a precise calculation requires a professional assessment of your home's unique moisture load, common recommendations are often presented in a chart format that considers both the square footage and the home's condition (e.g., loosely sealed, moderately sealed, tightly sealed). For a home up to 2,500 square feet, a dehumidifier with a capacity of 70 to 100 PPD at AHAM conditions is a common starting point, but this can increase significantly for larger or damper homes. For instance, a tightly sealed home of 5,000 square feet may require a unit with a capacity of 155 to 225 PPD.