This chapter describes several ways to cut heat exchanger cost. To obtain these benefits, user and manufacturer must work together. After-the-fact conclusions are drawn following the examples in the chapter. Section 15.1 will illustrate how less refrigerant is needed to operate an A/C system if the evaporator and condenser use smaller-diameter tubes. Users should define the minimum acceptable tube diameter. In the case described in Section 15.2, a workable quench oil cooler could have been furnished had a flaking problem been recognized beforehand, while the success of the furfural cooler described in Section 15.3 could have been ensured by selecting equipment adaptable to frequent cleaning. These are the kinds of requirements that should be in the specifications, as is noting whether noncode units are acceptable. Defining or anticipating site conditions is the responsibility of the specification writer. Otherwise, the rating engineer has no way of knowing of these needs.