The LBNL Residential Diagnostics Database (ResDB) contains blower
door measurements and other diagnostic test results for US homes. Most
of the data have been contributed by weatherization assistance programs
and residential energy efficiency programs. We analyzed the air leakage
measurements, using normalized leakage as the metric, of 134,000
single-family detached homes. Almost all 50 US states are represented.
We performed regression analyses to examine the relationship between
normalized leakage and various house characteristics. We identified
parameters that are useful as explanatory variables, including floor area,
height, vintage, and climate zone. Foundation type and whether ducts are
located outside or inside the conditioned space also were found to be
useful parameters for predicting normalized leakage. We developed a
regression model that explains approximately 68% of the observed
variability across US homes. A more spatially refined model for 4,500
California homes in ResDB explains 76% of the observed variability.
Comparison of the air leakage measurements before and after retrofit
shows a reduction in normalized leakage, i.e. an improvement in
airtightness, of 20% to 30%. Homes that are rated for energy efficiency
have normalized leakage values that are, on average, 30% lower than
non-rated homes. The resulted regression model can be used to predict
air leakage values for individual homes, and distributions for groups of
homes, based on their characteristics. For the US housing stock, the
regression model predicts normalized leakage to range between 0.22 and
1.95, with a median of 0.67.