Differential pressure measurement: High-precision thanks to state-of-the-art technology

Differential pressure measuring instruments can measure both positive and negative pressure as well as differential pressure. To achieve this, the devices must work extremely precisely, rely on smart technologies and thus be suitable for a wide range of applications. Intuitive operation is also an important feature of modern measuring instruments that can be operated via tablet or smartphone.

With its differential pressure gauges, Testo offers you numerous options for having the right measuring instrument for every situation. Differential pressure transducers, as well as various probes and sensors, are included in the range.

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Instruments for differential pressure measurement offer the following advantages:

  • Handy and easy to use
  • Robust and suitable for different working environments
  • Equipped with a large display for best overview of the readings
  • Versatile since optional accessories are available
  • Intuitive operation with no instruction needed

Testo's differential pressure gauges – large selection from classic to smart

Device with fixed probes

Differential pressure measuring device
Ideal for simple, daily routine measurements.

Device with connectable probes

Differential pressure measurement
Depending on the probe, measure not only differential pressure, but also further measurement parameters.

With smartphone operation

Measure differential pressure
Handy and smart: the measurement is handled and read out via smartphone or tablet.


Differential pressure
Optional probes with differential pressure sensor – ideal for pressure and flow.

Device with fixed probes

Device with connectable probes

With smartphone operation


Measuring differential pressure: Pay attention to the reference values

When measuring differential pressure, it is important to observe the so-called reference pressure. Because every measurement parameter relates to this one! The vacuum is the reference pressure when measuring absolute pressure, while the ambient pressure is relevant when measuring the relative pressure. As the user, you record two values, and the differential pressure measurement reveals the difference between the two values. A differential pressure measuring instrument is therefore used, which has two connections and is therefore able to record and display two values. Absolute pressure gauges measure the barometric pressure, whereby two types of barometric absolute pressure are available: 

  • Firstly, the pressure relating to the particular altitude
  • Secondly, the absolute pressure converted to sea level.

The converted absolute pressure is mainly used in meteorology and ensures the comparability of the values there. ‎‎The most commonly used value is the average value related to sea level: 1013.25 hPa.

Differential pressure measuring instrument
Differential pressure measuring instrument

An absolute pressure measuring instrument always has only one hose connection and cannot be zeroed. Accordingly, the differential pressure measuring instrument can be used to determine the relative pressure. The result of all measurements is a positive or negative value, which stands for a positive or negative pressure. Important: Differential pressure measurement can only be carried out with precision if the differential pressure sensors are functioning properly, which means that the instruments used must be highly sensitive. They must compensate for or tolerate different temperatures during differential pressure measurement and at the same time be as handy and robust as possible. Quite a big ask for a small measuring instrument! Testo's differential pressure gauges (and differential pressure sensors) are the right choice because these instruments are precise, sufficiently sensitive and cover a wide range of applications:

  • Can be used in heating engineering
  • Can be used in ventilation technology
  • For use in cleanrooms
  • Suitable for flow measurements

In order to be able to carry out differential pressure measurement accurately, highly developed instruments are required which measure the pressure accurately but are nonetheless easy to use. In order to be well prepared for every situation, instruments with connectable probes are used, for example, which can also record other measurement parameters.

Differential pressure gauge in use: the most common areas of application

Carrying out pressure measurement correctly: Preventing errors

Differential pressure gauge

Even though the differential pressure measuring instruments are ultra-modern devices that communicate with the smartphone and thus rely on the use of state-of-the-art technologies, human error can still cause the measured values to be incorrect, even with a highly sensitive differential pressure sensor. Firstly, it is important that the right pressure is applied to the right connection. The positive connection belongs to the positive pressure, the negative connection to the negative pressure. Other common errors include:

  • Measurements without a pitot tube in a dirty environment
  • Air filters not changed in good time
  • No precise regulation of the pressure difference in the clean room
  • Mixing up of + and - connections

Testing via differential pressure measurement

In differential pressure measurement, various pressures are measured. It is important that the right differential pressure measuring instrument is available for everyone. Whether you work in building technology or in industry, in research or in science: the pressure can only be measured with the appropriate instrument. A leak detector is also important, because it is not uncommon for an inspection to show that there is a leak. The instrument detects exactly where that is, and also detects all the common refrigerants.

More pressure measuring instruments from Testo

For extra safety: Differential pressure measurement in a vacuum

The vacuum gauge is just as high-precision as the other Testo measuring instruments. It is equipped for evacuating heat pumps or air conditioning systems and provides a manifold for every user. Various functions are combined in one instrument and the required readings are collected accurately and displayed clearly. Thus, all requirements can be fulfilled with a differential pressure sensor taking care of the most important part and ensuring increased safety in the company and in the tested systems.

Measuring pressure: Determine different pressures using the Testo manometer

Besides numerous other measurement parameters, pressure is one of the most important parameters of all. Different pressure types need to be measured, and Testo has the right instrument for you in each case. For example, for differential pressure measurement or for measuring the absolute pressure. It is often more practical to use one multifunction instrument than to use individual instruments. Digital manometers can also be found here. By the way: In air-conditioning and heating technology, differential pressure measurement is the most common measurement of all, which explains why Testo also focuses on the relevant instruments and why high-precision measuring instruments for this type of pressure measurement have been developed and are still being further developed.

Other pressure manometers include: