Engineering audits at state-owned buildings in Minnesota

Abstract

This paper describes the contents and analyzes the results of detailed engineering audits performed at 41 institutions owned by the State of Minnesota. These institutions include community colleges, state universities, office buildings, hospitals, and Department of Transportation regional facilities. The audits covered 270 buildings and include 2010 individual energy conservation recommendations. Implementing all these suggestions would cut energy use by 71 MBtu/ft 2-audited, equivalent to at least 32% of baseline energy use at these institutions. The cost to implement all these measures is $1.90/ft 2 with an average payback period of less than 8 yr (using 1978 fuel prices). Implementing only those items that pay back in less than 5 yr would save 47 MBtu/ft 2-audited at a cost of 29c/ft 2. The cost-effectiveness of different measures is a strong function of the type of measure. HVAC, power plant, and lighting measures tend to have short payback periods of about 3 yr. Envelope measures, on the other hand, have long payback periods, with an average of 23 yr.