This paper documents and compares the air infiltration levels experienced in five Twin Rivers townhouses before and after retrofit. The technique used to measure air infiltration rates was the tracer gas method, which relied upon automated equipment. Weather data as well as 5-min interval air infiltration measurements were used in the comparisons.

Analysis techniques included multiple regression, polar plotting, stemleaf plotting, and detailed comparisons of infiltration rates as influenced by temperature differences inside-to-outside the dwelling.

The results indicate that: the retrofitted townhouses are noticably less sensitive to wind direction, showing little or no increase in infiltration when the wind directly impinges on building surfaces; the post-retrofit infiltration rates average 36 percent less than the preretrofit data, with individual houses experiencing as much as a 48 percent decrease; and basement and attic retrofitting appear to be very influential in achieving the greatest reductions in air infiltration rates.