Purchasing new high efficient equipment will not necessarily reduce the cost of heating and cooling a home. Energy efficiency is not simply purchasing a new high SEER system, is about proper installation to manufactures specifications. A quality installation will save energy and money. The Annualized Fuel Utilization Efficiency (AFUE) rating provides the consumer with a number that represents the percentage of fuel efficiency achievable by gas and oil fired furnaces and boilers. How can a HVACR service technician verify that they have properly installed or serviced a system the manufacturers specified AFUE rating? This can only be accomplished through combustion analysis, an essential aspect of furnace and boiler efficiency . This training manual addresses: carbon dioxide formation and release, carbon monoxide generation, thermal heat transfer, and flame temperature. The manual includes steps and procedures to increase efficiency and reduce emissions are also included. Readers should expect to increase their knowledge of the combustion process and combustion control. Topics such as the dynamics of carbon dioxide production, the release of heat, and the oxygen relationship are discussed.