Abstract
Implementations of the heat balance integral method are discussed in which exponential functions are used in place of the familiar polynomial approximants. The rationale is based upon that of least-squares in that the use of `appropriate' basis functions can enhance solution accuracy. Whilst this is true in principle it is shown that considerable skill must be exercised when deviating from polynomial approximants. The discussions are illustrated by application to a familiar single-phase Stefan problem that is typical of heat transfer problems exhibiting decay-like spatial solution profiles.