Monitoring of Internal Moisture Loads in Residential Buildings

Reducing Thermal Losses and Gains With Buried and Encapsulated Ducts in Hot-Humid Climates

“…The relative humidity sensors used in this study are accurate in the hot attic conditions, and the dew point calculations used in data postprocessing have been rigorously verified. Furthermore, a long-term monitoring study that included 20 houses in Florida (Arena et al 2010) and a study of an early 1990s vintage home in Florida (Chasar and Wither 2012) found similar trends in attic dew point temperatures. Appendix A contains a more comprehensive discussion of this issue.…”

“…Although dew point is more sensitive to errors in relative humidity measurement at higher dry bulb temperatures, the rated inaccuracy does not account for the dew point trends. A long-term monitoring study conducted for the U.S. Department of Housing and Urban Development that included 20 houses in Florida found similar trends in attic dew point temperatures (Arena et al 2010). Explaining the cause of the changing dew point temperatures in the attics of these houses is outside the scope of this study, but possible explanations include solar moisture drive, along with moisture storage and evaporation in the building components, especially wood.…”

Moisture Research - Optimizing Wall Assemblies

“…Interior relative humidity levels generated with this method are higher than recorded in actual studies (Arena et al 2010) and result in overly pessimistic predictions for mold growth on the interior of the assembly.…”

“…Where this can be the case in older, leakier homes, homes built to today's code requirements or better could be seeing higher RH levels because of the tightness of the building shell, even when constructed with mechanical ventilation levels as prescribed in ASHRAE Standard 62.2 (2010). Data collected in an effort to validate the assumptions for the interior conditions in ASHRAE Standard 160-2009 (Arena et al 2010) show a range of wintertime indoor RH levels in 20 different homes in climate zone 5 (mid-30% to mid-50% RH levels). Also, several professionals consulted recently who are actively monitoring homes built with lower than average natural air change rates have noted RH levels above 40%.…”

Variability in Measured Space Temperatures in 60 Homes

“…Temperature data were collected at 15-minute intervals for an entire year, including living room, master bedroom, and outdoor air temperature (Arena et al 2010). The data were examined to establish the average living room temperatures for the heating and cooling seasons, the variability of living room temperatures depending on climate, and the variability of indoor space temperatures.…”