Optimum insulation thickness in wood-framed homes.

Abstract

New design methods must be developed to reduce energy waste in buildings. This study examines an economic approach to the design of thermal insulation in the home and demonstrates graphically that an optimum point of insulation thickness occurs where total costs of insulation and energy over the useful life of a building are a minimum. The optimum thickness thus determined exceeds that recommended by older design criteria and significantly reduces energy requirements for heating and cooling. An engineering heat loss analysis is applied to typical wood-framed wall and roof constructions, and total costs of insulation and energy are graphically shown for various thicknesses of insulation in several climates of the United States. Simple expressions are derived that may be used by designers and contractors to estimate optimum insulation thicknesses for any climate by using a series of curves. This method of design is new and results in greater total cost economy and better energy conservation than previous methods. Other ways of reducing heat loss in the home are also discussed.

Citation

Oviatt, A.E. 1975. Optimum insulation thickness in wood-framed homes. Gen. Tech. Rep. PNW-GTR-032. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 37 p.