LAKEVILLE, MN — A study founded by the Minnesota Dept. of Commerce concluded that Minnesota’s progressive energy code, one of the first in the nation to mandate mechanical ventilation and depressurization standards in new homes, was working. The latest version of the Minnesota residential energy code was implemented in April 2000, despite complaints by builders that the code was too complicated.

The study, conducted by Shelter Source, a training and energy consulting company, found that for the most part, recently built Minnesota homes are performing well. Investigators evaluated 43 Minnesota homes, which were built in 1994, 1998, and 2000. The results showed that the 2000 homes were 40% tighter than those built in 1994 and 28% tighter than those built in 1998.

The worrisome part of the report was that it documents a gradual trend away from atmospherically vented appliances. While all of the water heaters in the 1994 houses were atmospherically vented, only 14% of those in the 2000 houses were atmospherically vented.