ista's smart cooling meters deliver precise and reliable measurement.
Our cooling meters capture energy consumption with exceptional accuracy and long-term stability, helping you to improve transparency, reduce operating costs and support smarter energy management across your buildings.
Know exactly what’s being used — and where.
Streamline billing with precise data collection
Cut costs with long-life battery operation
Benefit from wear-free ultrasonic technology
Detect errors and tampering attempts early
Cooling insights that drive efficiency.
In an era of rising energy costs and growing demands for sustainability, accurate metering is more important than ever. ista’s cooling meters are designed to measure the precise amount of energy transferred through chilled water systems. Whether in residential buildings or large commercial setups, our meters provide the basis for fair billing, energy transparency, and efficient facility management. Thanks to their robust, MID-compliant design and advanced communication options, they are a future-proof, scalable solution.
The technology behind precise cooling measurement.
A cooling meter, also known as a BTU (British Thermal Unit) meter, is used to measure the thermal energy consumed in chilled water systems. It combines three key components: a flow sensor, two temperature sensors, and a microprocessor-based energy calculator. The flow sensor is installed in the return line, while the temperature sensors are placed in the supply and return lines. The meter calculates the transferred energy by comparing the temperature difference with the volume of water that has flowed through the system.
Ultrasonic cooling meters measure flow using ultrasonic signals rather than mechanical parts. This method is free from wear and tear, silent, and highly precise — even at low flow rates or in systems with poor water quality. Since there are no moving components, ultrasonic meters offer long-term stability, minimal maintenance and excellent durability, making them the preferred choice for modern energy monitoring.
At ista, we offer cooling meters for every building type and installation scenario. Our devices are developed with German engineering expertise, combining technical precision with a robust, field-tested design. Whether you are equipping a residential high-rise or a large-scale commercial property, our meters provide reliable performance and clear data for accurate energy billing.
Reliable data in every environment
Long-term efficiency with zero wear
Built-in intelligence for smarter systems
Streamline your billing with our utility solutions.
Take advantage of our integrated utility billing system that consolidates water, energy, and other services into a single, easy-to-manage platform.
Facts & figures
6,300 employees
20 countries
3.7 mil. t CO₂ emissions avoided
43 mil. radio devices
14 mil. utilisation units
Precision and accuracy in one device: ista's ultego III
The ultego III smart plus and ultego III perfect are part of ista’s latest generation of cooling meters — developed for flexible use across a wide range of building types and system sizes. Designed for use in systems with water as the cooling medium, the compact ultego III smart plus integrates a flow sensor, two external temperature sensors, and a high-precision energy calculator. If needed, the calculator can be mounted separately, and sensor cable lengths can be specified to suit installation requirements.
With flow rates ranging from 0.6 to 60 m³/h, the meter is suitable for applications ranging from individual transfer stations to large multi-unit buildings. Its robust, all-metal DuraSurface™ housing and flexible installation options (horizontal, vertical or even upside down) ensure stable performance in tight spaces and areas with high humidity. Integrated communication modules — including M-Bus, wireless M-Bus, and pulse output — enable seamless integration into remote reading and building automation systems. Compliant with the European Measuring Instruments Directive (MID), the ultego III smart plus provides a durable, future-proof metering solution for scalable energy monitoring.
Features of the ultego III
- Accurate, reliable, wear-free measurement
- Battery lifetime up to 11 years
- Precise detection of even the smallest flow rates
- Resistant to dirt and mess
- Extremely low energy consumption
- Low pressure loss
- Fast, intelligent temperature measuring grid
- Can be installed horizontally or vertically ( III ultego smart plus even upside down with removable calculator )
- Flow measuring range of 1:100 to EN 1434, total 1:1000
- Tamper-proof by sealing
- Self-diagnosis
Frequently asked questions
A cooling meter, also known as a BTU meter, measures the energy consumed in chilled water systems. They are commonly used in apartment buildings, transfer stations and commercial cooling networks to ensure fair billing and enable energy monitoring.
As they have no moving parts, ultrasonic meters are wear-free and maintain their precision over many years, even at low flow rates or in dirty water.
Depending on the configuration, the battery in ista cooling meters has a lifespan of up to 11 years. This allows for uninterrupted, long-term operation without the need for costly servicing.
Yes, ista cooling meters support MBus and Wireless MBus, as well as pulse output, making them ideal for remote or automated readings and integration into BMS or energy monitoring platforms.
Yes. All meters are MID-certified and compliant with EN 1434 standards, ensuring they meet the legal requirements for energy billing in the UAE and across international markets.
No time right now? Download for later:
"Prodcut brochure: ultego III smart plus
PNG - 13 KB