This guide contains information on the knowledge and skills identified by industry as essential to the job performance of heating, air-conditioning, and refrigeration technicians. It is intended to assist training providers in public and private institutions, as well as in industry, to develop and implement training that will provide workers with the competencies needed to gain employment as technicians and to advance within the field. The publication contains six sections. The first section defines skill standards, provides suggestions for using them, and explains how they were developed. The second section lists the core knowledge standards in communication, mathematics, and science. The third section lists the core occupational skills standards in these areas: safety and environment, electrical principles, electric motors, controls, refrigeration, heating, air conditioning, and piping. Occupation-specific skill standards for residential and light commercial heating, air conditioning, and heat pumps, and commercial conditioned-air systems and refrigeration are listed in the fourth section. In the fifth section, standards for workplace behaviors, including ethics, environment, communication, professionalism, and problem solving, are provided. The final section contains skill standards matrixes for core skills and occupational skills. An appendix contains a skills matrix that relates all the skill standards to various residential and commercial applications. (KC)