Btu（热量）表被广泛用作公用工程计量装置和评估太阳能系统性能的低成本仪器。在安装在正在评估的主动太阳能DWH系统中之前，大约35 Btu仪表进行了系统测试。试验表明，流量计精度的变化范围很广，总体Btu的精度在1%到30%之间，总体流量的精度在1%到20%之间，流量和温差在0.03 l/s（0.5 g/m）到0.19 l/s（3.0 g/m）和5.6°C（10°F）到55.6°C（100°F）之间。测量误差被发现是由于温度传感器无响应、流量传感器对低流速不敏感、质量控制和各种电子问题造成的。 得出的结论是，在安装之前，设备的验收测试至关重要。在高优先级项目中，需要定期进行功能检查和/或校准，以确保数据质量。引用:ASHRAE交易，第88卷，第2部分，加拿大多伦多

Btu (heat) meters are widely utilized as a utility metering device and as a low cost instrument for evaluating performance of solar energy systems. Approximately 35 Btu meters were systematically tested prior to installation in active solar DWH systems under evaluation. The tests indicated wide variations in meter accuracy generally ranging from one to thirty percent for totalized Btu's and one to twenty percent for totalized flow at flow rates and differential temperatures ranging from 0.03 l/s (0.5 g/m) to 0.19 l/s (3.0 g/m) and 5.6°C (10°F) to 55.6°C (100°F). Measurement errors were found to be due to non-responsive temperature sensors, flow sensors not sensitive to low flow rates, quality control and various electronic problems. It was concluded that an acceptance test of a device was essential prior to installation. On high priority projects, periodic functional checks and/or calibrations are desirable to assure quality data.