the series 230 uhm is a highly accurate and stable btu meter. it utilizes ultrasonic technology to measure household heating and cooling energy consumption. the series uhm is a compact meter that has been designed to incorporate the flowmeter and calculator all in one unit for simplification of the unit’s installation. the 8digit led display makes reading the measured value simple and easy. the compact size and lack of moving parts makes the series uhm a low maintenance unit. these features make it great for installation on chillers, and boilers.