Energy & Heat Flow Measurement

We provide clamp on non-invasive energy & heat flow measurement and flow meter hire/sales services.

The following Flexim flow meters are for hire or sale. Alternatively, we offer on-site testing by our engineers.

Contact us today on +353 1 484 7832 or to discuss your requirements.

Click here to view sample flow test reports.

FLUXUS® BTU Thermal Energy Meters

FLUXUS® BTU Thermal Energy Meter

FLUXUS BTU allows the easy determination of the energy flow in a system, and thus the information needed to make changes for energy efficiency.

With temperature measurements made at the inlet and at the outlet of a system and flow measurement at the outlet, FLUXUS calculates the energy flow within that system. 

All this is done with clamp-on transducers mounted on the outside of a pipe -
without process interruption and without production stop.

FLUXUS will display the actual energy flow through the system and, if needed, totalize the heat flow in order to obtain the energy quantity. The values can easily be transmitted to a PC for display and analysis.


  • Measurements in cooling water, boiler feed water, condensate and heat circuits,
  • Temporary replacement of defective wetted heat meters,
  • Optimization of heating & cooling systems in large buildings (facility management),
  • Optimization of refrigeration & air-conditioning systems of industrial processes,
  • Field measurement for energy consulting.
flexim thermal measurement

Flexim FLUXUS Flow meters - Ultrasonic

FLUXUS® F601 - Portable / for Energy & Heat flow hire service

Flexim FLUXUS Flow meters - Ultrasonic - for liquids

The FLUXUS® F601 is the successor of the well known ADM 6725, which was famed for its reliability.

An ideal tool for service work and quick control ultrasonic measurements. The clamp-on flow transducers are simply mounted onto the pipe from the outside and are thus quickly installed, without process interruption and without production stop.

The measurement is pressure independent and can take place on pipes of almost any materials and on almost any liquid. The flow meter is ideal for chemically aggressive media.

Only two transducer pairs are needed to cover the diameters most common in industrial applications (DN10 to DN2500), the full transducer range covers DN6 to DN6500.

To start the measurement, you only have to mount the transducers on the pipe, enter the pipe and medium parameters and adjust the distance between the transducers as indicated by the meter. No zeroing procedure is necessary.

The FLUXUS F601 portable clamp-on flow meter is also available in an "Energy" and "Multi-functional" version, allowing the measurement of  thermal energy / BTU flows and making the flow meter the ideal companion for the analysis or auditing of heating and chiller plants. The collected data can be used to perform a complete energy balance or to assist during process monitoring and optimisation.



The F721 is FLEXIM’s next generation of advanced non-invasive ultrasonic flow metering for liquids and gases. Besides its new look, it boasts a completely re-designed hardware platform with a 32 bit embedded ARM processor for powerful signal processing. This allows for accurate and reliable measurement at even the most difficult applications.

Offering a far better signal to noise quality, a greater measurement range, signal improvements giving better signal evaluation and processing, nearly 10-fold faster measurement cycles than its predecessor, the FLUXUS 70X, and virtually unlimited data storage, the 721 flow meter surpasses any other non-intrusive ultrasonic flowmeter in terms of accuracy, reliability and versatility. Even low flows down to only a few litres per hour can be recorded accurately.

The F721 offers non-intrusive flow measurement of virtually any kind of liquid or gas, from the smallest tubing to the largest penstock, independent of the pressure inside the pipe and over a very large temperature range. This makes it the flowmeter of choice for a very wide range of applications in virtually any industrial sector, and is especially useful for measurements related to energy efficiency.

The F721 is the ideal solution to tap energy efficiency potentials non-intrusively, in HVAC applications as well as in industrial processes. Whether it is used for thermal power measurement in district heating networks or for monitoring the efficiency of an industrial heat exchanger, non-intrusive measurement never affects the safe supply in any way. With its excellent sensitivity for low flows and with highly accurate and paired temperature sensors, the F721 is particularly suited to accurate measurement of energy consumption in climatisation systems.
With regard to gases, the G721 is the perfect tool to measure the consumption of costly compressed air - non-intrusively without any potential for possible leaks.