How Insulating Concrete Form vs. Conventional Construction of Exterior Walls Affects Whole Building Energy Consumption: Results from a Field Study and Simulation of Side-by-Side Houses

Thomas W. Petrie, Jan Kosny, André O. Desjarlais, Jerald A. Atchley, Phillip W. Childs, Mark P. Ternes, and Jeffrey E. Christian, Oak Ridge National Laboratory

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Abstract

Results are given from a field investigation of side-by-side houses in Knoxville, Tennessee. The houses were identical except one had insulating concrete form (ICF) exterior walls and the other had conventional wood-framed exterior walls. Monitoring commenced in July 2000 and continued for eleven months. The houses were unoccupied and operated on the same simple schedules. The total energy consumption from July 2000 through June 2001 (estimated for June 2001) showed that the ICF house used 7.5% less energy than the conventional house.

The monitoring provided data sufficient to validate annual energy usage models of the two houses as they were tested. The validated models for the unoccupied houses on simple schedules were exercised for a range of climates that included heating dominated and cooling dominated. TMY2 weather data were used to simulate the different climates. The ICF house used 5.5% to 8.5% (6.8% in the Knoxville climate) less energy annually than the conventional house. In Knoxville, changing from unoccupied houses with simple operation to normal occupancy and operation increased the annual savings for the ICF house relative to the conventional house to 9.2%. This advantage of the ICF house over the conventional house decreased only slightly to 9.0% when minimal energy usage was postulated for both houses during the swing season in East Tennessee. During this approximately 15 week period of mild weather the test houses were operated without any heating or cooling. There were wider variations of air temperature in the conventional house than in the ICF house.