Use of Insulated Concrete Form (ICF) Construction for Energy Conservation in Residential Construction

Abstract

As a nation the United States must reduce its dependence on imported energy resources. Net imports of foreign oil as a percentage of total U.S. oil demand have increased from 37% in 1980 to 55% in 2001 and are predicted to increase to 65% by the year 2016. Since heating and air conditioning account for 44% of the energy usage in a typical U.S. home, residential energy conservation techniques hold great promise for significant savings. Insulated concrete form (ICF) construction is a promising construction technique for both residential and commercial construction. Some advantages of ICF construction include: reduced construction time, compatibility with any inside or outside surface finish, insect resistance, strength, noise reduction, reduced infiltration, significant and continuing energy savings, lower HVAC capital costs for the building, and 12” (30 cm) wide window sills. Disadvantages of ICF construction include: resistance from builders and sub-contractors unfamiliar with the construction technique, higher material costs, the necessary custom window and door openings, and the difficulty and expense of making changes once the walls are in place. Even though the material costs are higher than typical (stick-frame) construction, labor savings might result in overall savings. In this paper actual energy usage for an ICF house constructed in 1998 is compared to the energy usage for a 1988 conventional stick-frame building. Comparison of these two buildings indicates a 75% reduction in energy usage per square foot per degree-day for the ICF building when compared to the stick-frame building. During this same time period, energy (gas) usage for heating and hot water decreased 85%. Computer simulations were made for both an ICF wall and for a conventional frame wall. These computer simulations indicate significant saving potential for the ICF wall when compared to a conventional frame wall section. In addition these simulations illustrate dramatically the effect of separating the thermal resistance and thermal capacitance inherent in this “sandwich” construction.