FINDING the FLAWS in SUPERINSULATION Figure 1. A chaseway for furnace and water-heater flues. The fiberglass batt used to block opening is streaked with dirt from leaking air. Figure 2. The top of a partition viewed from the attic of a split-level house. Note that there's no blocking atop the wall-a problem in every split-level in the study. The thermal bugs in these 144 superinsulated houses were much the same as in any housing stock. So what have we learned? In 1980, 144 low-energy houses were built in Minnesota as part of a demonstration project called the Energy Efficient Housing Design (EEHD) program. Twenty-three builders participated in the program, and built from two to twelve houses each. The