标准221规定了一种现场评估和测试方法，以测量和评分已安装的整体式HVAC系统在提供冷却或加热能力或冷却效率方面的性能。本标准*定义了冷却和加热系统输送能力和冷却系统效率的性能评分方法*建立了气流、温度、焓和功率的统一测量方法和测试程序*规定了测试仪器、规范，执行此类测量和试验的校准要求*规定了所需的数据和要使用的计算*适用于单区整体分离和封装直接膨胀（DX）冷却、空气- 任何容量的源热泵和燃烧炉HVAC系统，以及强制空气分配系统

Standard 221 prescribes a field evaluation and test method to measure andscore the performance, in terms of delivered cooling or heating capacity or cooling efficiency, of an installed unitary HVAC system.This standard* Defines performance scoring methods for cooling and heating system delivered capacity and cooling system efficiency* Establishes uniform methods of measurements and testing procedures for airflow, temperature, enthalpy, and power* Specifies test instruments, specifications, and calibration requirements for performing such measurements and tests* Specifies data required and calculations to be used* Applies to single-zone unitary split and packaged direct expansion (DX) cooling, air-source heat pump, and combustion furnace HVAC systems of any capacity and with forced-air distribution systems