Controlling Indoor Humidity in Residential Environments

Humidity is often overlooked when it comes to providing a comfortable and healthy indoor environment. Although ASHRAE recommends maintaining relative humidity between 30% and 60%, humidity is rarely monitored in residential settings.

Excess humidity can cause a host of issues for both the building structure and the building inhabitants. High humidity can cause occupants to feel cooler during the winter or hotter during the summer, while low humidity can cause dryness and itching. High humidity can also lead to health problems by promoting the growth of mold, dust mites, and bacteria which can trigger allergic responses or asthma in building occupants. Uncontrolled humidity can also lead to condensation forming on cold surfaces which can damage building materials.

There are a number of strategies which can be utilized to properly control indoor humidity which should be considered during construction or may be installed in buildings which have humidity problems.

  • Remove indoor moisture generated by cooking, bathing, or drying clothes directly at the source and vent it directly to the exterior.
  • Ensure the building has sufficient ventilation to remove humidity generated by occupants, if the building is too tight mechanical ventilation may be required to bring fresh air indoors. Outdoor air may need to be dehumidified before being brought inside for buildings in humid climates.
  • Grade site and crawlspace to provide proper drainage. Install a vapor barrier in the crawl space to prevent moisture from entering the building from below and ensure the crawl space is properly ventilated.
  • Fix any water leaks from the building envelope or plumbing fixtures and prevent any standing water issues.
  • Install a central HVAC system which can also monitor relative humidity and provide dehumidification or provide a standalone dehumidifier.

By incorporating a combination of these strategies proper humidity control can be achieved to provide an optimum living environment to building tenants.