High humidity creates many problems in the home. For these residents of the house, it can lead to allergies and other respiratory problems, as well as compromised perceived indoor air quality (IAQ). Additionally, it often increases the amount of energy needed in the home, promotes the growth of dust, mold and bacteria, and in some cases leads to damaged building components.
Despite many home-related humidity concerns, there is little no measured data available on actual indoor humidity levels in American homes. That's why the U.S. Department of Housing and Urban Development (HUD) funded Steven Winter Associates, Inc. (SWA) to collect humidity data in home rooms.
"The purpose of this study is to aid the efforts already started by the ASHRAE Standards Committee 160P Design Guidelines for Preventing Water Damage to Buildings and others to develop moisture modeling tools and related technical standards," explained Lois Stage , a senior engineer with SWA, he recently authored a report on Indoor Air Quality Monitoring Data (IAQ): Part II. "In order to support these standard initiatives, it cannot be overemphasized that there is a clearer understanding of the occurrence of high levels of indoor humidity, and the contributing factors.
Under a project funded by the Department of Housing and Urban Development, U12-011/ UX100-011 collected year-round indoor temperature and humidity data from 60 homes in three different regions of the United States: the warm, humid Southeast Asia, the cold Northeast, and the Pacific Northwest . In addition, SWA collects house characteristics data including occupancy levels, insulation levels, appliance efficiencies, envelope leaks, and plumbing leaks.
To monitor temperature and humidity, U12-011/ UX100-011 engineers choose Onset, the wandering U12 data logger. A battery-operated device is used to keep a clock of humidity levels, even during power outages. Then use the included HOBO Ware®Pro software to convert the data into a time-stamped graph that can be displayed on the company's personal computer. -
When we looked at the monitoring options, we were impressed with the small, battery-operated HOBO data loggers, "Stage Memories." The ease of installation, accuracy, and cost-effectiveness of these devices clearly outpaced travel and man-hours There are costs associated with making additional site visits. "
A year-long analysis revealed some insights into SWA. While some confirmed some common industry assumptions, there were also some surprises. For example, analysis of the data showed that SWA's home in oceanic climates consistently saw indoor relative humidity above 50 percent, higher than the average detected in other regions. However, cold regions have moisture issues
Furthermore, the analysis revealed some commonalities among all three regions. For example, windows and bathrooms are common areas where mold or moisture damage is visible. However, there are clear regional differences as well as U12-011/ UX100-011 .
Ÿ In the hot, humid southeast, humidity issues seem to occur with newer, more efficient homes in the area. One idea is that because these homes are more comfortable, fewer space conditions are required during these months, which can lead to higher indoor relative humidity levels
Ÿ Many homes in the cold Northeast have water leaks in the basement, and all homes have partially unfinished basements. Moisture problems in homes in this group also had a higher average air change rate compared to those that did not.
Ÿ In the Pacific Northwest marine environment, all moisture-problematic homes have a full or partial crawl space that does not have a well-sealed moisture barrier for dirt
An important insight from our monitoring and analysis is that, in general, there are no statistically significant correlations across climate zones. Instead, each region has specific problems that need to be addressed, "Ladies Arena Watch." Rather than setting blanket recommendations for humidity control, it will be important to establish standards and guidelines applicable to the specific challenges of each region
