Image
  1. Home
  2. testo 400

testo 400 - Universal IAQ instrument

0560 0400 01
testo 400 Universal IAQ instrument
testo 400
testo 400 Universal IAQ instrument
testo 400 Universal IAQ instrument
testo 400 Universal IAQ instrument
testo 400 Universal IAQ instrument
testo 400 Universal IAQ instrument
Application testo 400
Application testo 400
Application testo 400
Application testo 400
Application testo 400
  • Comprehensive IAQ Measurement – Measures all IAQ parameters, including flow velocity, temperature, humidity, pressure, CO2, CO, and more.
  • Smart Measurement Programs – Intuitive programs for HVAC grid measurements (EN ISO 12599, ASHRAE 111), PMV/PPD, turbulence, and more.
  • Built-in Differential Pressure Sensor – High-precision, location-independent sensor for accurate measurements.
  • Extensible with Probes – Compatible with Bluetooth® and cable probes for flexible measurement options.
  • Data Management & Reporting – Includes analytical software for easy data analysis, reporting, and customer management.
  • The testo 400 is the ultimate tool for professionals in indoor air quality (IAQ) measurement. It offers a wide range of features including intuitive measurement programs, high-precision sensors, and the ability to connect a variety of probes. It’s the ideal instrument for measuring, analysing, and documenting all IAQ and comfort parameters, providing full compliance with standards.
    • not available
    • not available
    The testo 400 is a highly advanced, universal IAQ instrument designed to support professionals in the fields of air conditioning, ventilation, and environmental monitoring. It allows users to measure, analyse, and document all IAQ and comfort parameters using a single, intuitive device. Whether you're working on air flow measurements, temperature and humidity levels, or assessing air quality, the testo 400 offers the versatility and accuracy required to get the job done.

    With high-quality measuring technology and smart measurement assistants, the testo 400 supports a wide range of applications, from standard-compliant HVAC grid measurements to long-term monitoring of indoor air quality. Its built-in sensors for differential pressure and absolute pressure enable location-independent, highly precise measurements.

    You can also connect the testo 400 with a broad range of compatible Bluetooth® and cable probes, making it flexible for any measurement task. This includes flow velocity, CO2 and CO, radiant heat, illuminance, and turbulence. It even integrates with the testo 420 volume flow hood to manage volume flow measurement at large air inlets and outlets.
    The instrument also supports long-term monitoring via an IAQ data logger for continuous air quality measurements. Furthermore, the testo 400 offers smart features such as measurement programs tailored to specific standards (like EN ISO 7730 and ASHRAE 55), and customer management tools to help you work efficiently on-site.

    For ease of use, it comes with a smart-touch display for quick, intuitive operation. Measurement results and reports can be sent directly via WLAN or Bluetooth®, and further analysis and documentation can be done using the testo DataControl PC software.

    Ideal For
    • HVAC Professionals: Perfect for air flow, temperature, humidity, and ventilation system inspections.
    • Environmental Monitors: Helps ensure compliant indoor air quality in commercial or residential spaces.
    • Long-Term IAQ Monitoring: Offers the tools to measure and monitor IAQ over extended periods.

    1 x testo 400 universal IAQ instrument, including transport case for air flow measurements, testo DataControl software, connection hose, mains unit with USB cable, calibration protocol and instruction manual.

    Temperature - NTC

    Measuring range
    -40 to +150 °C
    Accuracy
    ±0.5 % of mv ±1 Digit (Remaining Range)
    ±0.4 °C ±1 Digit (+75 to +99.9 °C)
    ±0.2 °C ±1 Digit (-25 to +74.9 °C)
    ±0.4 °C ±1 Digit (-40 to -25.1 °C)
    Resolution
    0.1 °C

    Temperature - TC Type K (NiCr-Ni)

    Measuring range
    -200 to +1370 °C
    Accuracy
    ±(0.3 °C + 0.1 % of mv) ±1 Digit
    Resolution
    0.1 °C

    Differential pressure (internal sensor) - Piezoresistive

    Measuring range
    0 to +200 hPa
    Accuracy
    ±(0.1 hPa + 1.5 % of mv) ±1 Digit (25.001 to 200 hPa)
    ±(0.3 Pa + 1 % of mv) ±1 Digit (0 to 25 hPa)
    Resolution
    0.001 hPa

    Comfort probes

  • Comfort probes
    Turbulence probe (digital), wired
    Turbulence probe (digital), wired: for determining the degree of turbulence and draught risk according to EN ISO 7730 / ASHRAE 55 – measuring range 0 to +5 m/s, 0 to +50 °C
      :
      0628 0152
    • Comfort probes
      CO2 probe (digital) with Bluetooth® including temperature and humidity sensor
      CO₂ probe (digital) with Bluetooth® including temperature and humidity sensor: for measuring the indoor air quality in offices, production areas or storage facilities – measuring range 0 to 10,000 ppm, -10 to +50 °C, 5 to 95% RH
        :
        0632 1551
      • Comfort probes
        Lux probe (digital) for measuring illuminance, wired
        Lux probe (digital), wired: for measuring illuminance in workplaces (e.g. offices, production areas) – measuring range 0 to 100,000 lux
          :
          0635 0551
        • Comfort probes
          CO2 probe (digital) including temperature and humidity sensor, wired
          CO₂ probe (digital) including temperature and humidity sensor, wired: for measuring the indoor air quality in offices, production areas or storage facilities – measuring range 0 to 10,000 ppm, -10 to +50 °C, 5 to 95% RH
            :
            0632 1552
          • Comfort probes
            CO2 probe head including temperature and humidity sensor
            CO₂ probe head including temperature and humidity sensor: for attachment to universal Bluetooth® or cable handle – measuring range 0 to 10,000 ppm, -10 to +50 °C, 5 to 95% RH
              :
              0632 1550
            • Comfort probes
              CO probe (digital) with Bluetooth®
              CO probe (digital) with Bluetooth®: for measuring carbon monoxide in indoor areas (e.g. boiler rooms) – measuring range 0 to 500 ppm
                :
                0632 1271
              • Comfort probes
                CO probe head
                CO probe head: for attachment to universal Bluetooth® or cable handle – measuring range 0 to 500 ppm
                  :
                  0632 1270
                • Comfort probes
                  CO probe (digital), wired
                  CO probe (digital), wired: for measuring carbon monoxide in indoor areas (e.g. boiler rooms) – measuring range 0 to 500 ppm
                    :
                    0632 1272
                  • Comfort probes
                    Globe probe Ø 150mm
                    For the measurement of radiant heat according to ISO 7243, ISO 7726, DIN EN 27726 and DIN 33403
                      :
                      0602 0743
                    • Comfort probes
                      WBGT kit testo 400
                      WBGT kit for universal IAQ measuring instrument testo 400
                        :
                        0618 7220
                      • Food probes

                        Humidity probes

                      • Humidity probes
                        Humidity/temperature probe (digital) with Bluetooth®
                        Humidity/temperature probe (digital) with Bluetooth®: for measurements in rooms, ventilation ducts, refrigeration systems and heat pumps – accuracy ±2% RH / ±0.5 °C, measuring range 0 to 100% RH / -20 to +70 °C
                         
                          :
                          0636 9731
                        • Humidity probes
                          Humidity/temperature probe (digital), wired
                          Humidity/temperature probe (digital), wired: for measurements in rooms, ventilation ducts, refrigeration systems and heat pumps – accuracy ±2% RH / ±0.5 °C, measuring range 0 to 100% RH / -20 to +70 °C
                           
                            :
                            0636 9732
                          • Humidity probes
                            Humidity/temperature probe head
                            Humidity/temperature probe head: for attachment to universal Bluetooth® or cable handle – accuracy ±2% RH / ±0.5 °C, measuring range 0 to 100% RH / -20 to +70 °C
                              :
                              0636 9730
                            • Humidity probes
                              High-precision humidity/temperature probe (digital) with Bluetooth®
                              High-precision humidity/temperature probe (digital) with Bluetooth®: for measurements in cleanrooms and laboratories, and critical processes in the pharmaceutical, industrial and food sectors, as well as in storage, refrigerated and work rooms or in air conditioning/ventilation ducts - accuracy: ±(0.6% RH + 0.7 % of m.v.) (0 to 90% RH) / ±0.3 °C (+15 to +30 °C)
                                :
                                0636 9771
                              • Humidity probes
                                High-precision humidity/temperature probe (digital), wired
                                High-precision humidity/temperature probe (digital), wired: for measurements in cleanrooms and laboratories, and critical processes in the pharmaceutical, industrial and food sectors, as well as in storage, refrigerated and work rooms or in air conditioning/ventilation ducts - accuracy: ±(0.6% RH + 0.7 % of m.v.) (0 to 90% RH) / ±0.3 °C (+15 to +30 °C)
                                 
                                  :
                                  0636 9772
                                • Humidity probes
                                  High-precision humidity/temperature probe head: for attachment to a universal Bluetooth® or cable handle – accuracy: ±(0.6% RH + 0.7 % of m.v.) (0 to 90% RH) / ±0.3 °C (+15 to +30 °C)
                                    :
                                    0636 9770
                                  • Humidity probes
                                    Robust humidity/temperature probe (digital) - for temperatures up to +180 °C, wired
                                    Robust humidity/temperature probe (digital) for temperatures up to +180 °C, wired: for measurements in industrial exhaust air, in bulk materials and in climatic test cabinets – accuracy ±2% RH (2.1 to 98% RH) / ±0.4 °C (0.1 to +50 °C), measuring range 0 to 100% RH / -20 to +180 °C
                                     
                                      :
                                      0636 9775
                                    • Humidity probes
                                      testo 605i
                                      Automatic calculation of the dew point and wet-bulb temperature
                                        :
                                        0560 1605
                                      • Humidity probes
                                        testo 605i
                                        testo 605i - thermohygrometer operated via smartphone
                                          :
                                          0560 2605 02
                                        • Pitot tubes

                                          Pressure probes

                                          Surface probes

                                          Temperature probes

                                        • Temperature probes
                                          testo 805i
                                          Non-contact infrared measurement of surface temperature
                                            :
                                            0560 1805
                                          • Temperature probes
                                            High-precision immersion/penetration probe (digital)
                                            High-precision immersion/penetration probe (Pt100 temperature sensor, digital) for temperature measurements in liquids and pastes – measuring range -80 to +300 °C, accuracy up to ±0.05 °C
                                              :
                                              0618 0275
                                            • Temperature probes
                                              Immersion/penetration probe (digital)
                                              Immersion/penetration probe (digital) with Pt100 temperature sensor: for temperature measurements in liquids and pastes – measuring range -100 to +400 °C, accuracy up to ±0.15 °C
                                                :
                                                0618 0073
                                              • Temperature probes
                                                Glass-coated laboratory probe (digital)
                                                Glass-coated laboratory probe (Pt100 temperature sensor, digital) for temperature measurements in aggressive media – measuring range -50 to +400 °C
                                                  :
                                                  0618 7072
                                                • Temperature probes
                                                  Robust, fast-action air probe (digital)
                                                  Robust, fast-action air probe (digital)
                                                    :
                                                    0618 0072
                                                  • Temperature probes
                                                    Flexible temperature probe (digital)
                                                    Flexible temperature probe (digital) with Pt100 temperature sensor: for temperature measurements in locations that are difficult to access and in liquids – measuring range -100 to +260 °C
                                                      :
                                                      0618 0071
                                                    • Temperature probes
                                                      Pipe wrap probe with NTC temperature sensor for measurements on pipes (Ø 5-65 mm)
                                                      Pipe wrap probe (NTC temperature sensor) for measuring the surface temperature of pipes (Ø 5-65 mm) – measuring range -60 to +130 °C
                                                        :
                                                        0615 5605
                                                      • Temperature probes
                                                        Temperature probe with Velcro and NTC temperature sensor
                                                        Temperature probe with Velcro (NTC temperature sensor) for measuring the surface temperature of pipes – measuring range -50 to +70 °C
                                                          :
                                                          0615 4611
                                                        • Temperature probes
                                                          Waterproof immersion/penetration probe with NTC temperature sensor
                                                          Waterproof immersion/penetration probe (NTC temperature sensor) for temperature measurements in liquids and semi-solid media – measuring range -50 to +150 °C, accuracy ±0.2 °C (-25 to +74.9 °C)
                                                            :
                                                            0615 1212
                                                          • Temperature probes
                                                            Robust air probe with NTC temperature sensor
                                                            Robust air probe (NTC temperature sensor) with a short response time, for measuring air temperature – measuring range -50 to +125 °C, accuracy ±0.2 °C (-25 to +80 °C)
                                                              :
                                                              0615 1712
                                                            • Temperature probes
                                                              Clamp probe with NTC temperature sensor for measurements on pipes (Ø 6-35 mm)
                                                              Clamp probe (NTC temperature sensor) for measuring the surface temperature of pipes (Ø 6-35 mm) – measuring range -40 to +125 °C
                                                                :
                                                                0615 5505
                                                              • Temperature probes
                                                                Robuster Luftfühler, TE Typ K
                                                                Short response time – due to exposed sensor design.
                                                                  :
                                                                  0602 1793
                                                                • Temperature probes
                                                                  Fast-action surface probe with sprung thermocouple strip
                                                                  Fast response time (3 seconds) thanks to the thermocouple strip
                                                                    :
                                                                    0602 0393
                                                                  • Temperature probes
                                                                    Fast-reaction paddle surface probe
                                                                    Fast-reaction paddle surface probe (TC type K) - Measuring range: - 0 to +300°C
                                                                      :
                                                                      0602 0193
                                                                    • Temperature probes
                                                                      Efficient, waterproof surface probe with small measurement head
                                                                      Fast Response Time  – Ensures quick and accurate measurements.
                                                                        :
                                                                        0602 0693
                                                                      • Temperature probes
                                                                        Fast-action surface probe with sprung thermocouple strip
                                                                        Fast response time (3 seconds) thanks to the thermocouple strip
                                                                          :
                                                                          0602 0993
                                                                        • Temperature probes
                                                                          Magnetic probe (TC type K) - for surface temperatures
                                                                          Thermocouple type K 
                                                                            :
                                                                            0602 4792
                                                                          • Temperature probes
                                                                            Magnetfühler, Haftkraft ca. 10 N, mit Haft-Magneten
                                                                            Self-adhesive thanks to a magnet: probe for measuring surface temperature on metal surfaces
                                                                              :
                                                                              0602 4892
                                                                            • Temperature probes
                                                                              Waterproof surface probe with widened measurement tip
                                                                              Extra-wide measuring tip – ideal for accurate readings on flat surfaces.
                                                                                :
                                                                                0602 1993
                                                                              • Temperature probes
                                                                                Pipe wrap probe with velcro strip
                                                                                With Velcro: makes it easy to attach the surface probe to pipes with a diameter of up to 120 mm
                                                                                  :
                                                                                  0628 0020
                                                                                • Temperature probes
                                                                                  Pipe wrap probe for pipe diameter 5 to 65 mm
                                                                                  With clamping bracket: enables quick, easy attachment of the probe to pipes with a diameter of 5 to 65 mm
                                                                                    :
                                                                                    0602 4592
                                                                                  • Temperature probes
                                                                                    Clamp probe for measurements on pipes
                                                                                    Clamp probe (TC type K) for temperature measurements on pipes with Ø 15-25 mm – Measuring range -50 to +100°C, briefly up to +130°C
                                                                                      :
                                                                                      0602 4692
                                                                                    • Temperature probes
                                                                                      Efficient and fast-action immersion probe, waterproof
                                                                                      Short response time of 2 seconds
                                                                                        :
                                                                                        0602 0593
                                                                                      • Temperature probes
                                                                                        Fast-action, waterproof immersion/penetration probe
                                                                                        Fast 3-Second Response Time – Thermocouple strip enables quick and precise measurement.
                                                                                          :
                                                                                          0602 2693
                                                                                        • Temperature probes
                                                                                          Tauch-Messspitze, biegsam, TE Typ K
                                                                                          Immersion measuring tip with TC plug type K - for fast temperature measurements
                                                                                            :
                                                                                            0602 5792
                                                                                          • Temperature probes
                                                                                            Immersion measurement tip, flexible, for measurements in air
                                                                                            Flexible immersion measuring tip (TC type K) - Measuring range: -40 to +1000°C
                                                                                              :
                                                                                              0602 5693
                                                                                            • Temperature probes
                                                                                              Waterproof immersion/penetration probe, TC Type K
                                                                                              Fast response time – approx. 7 seconds.
                                                                                                :
                                                                                                0602 1293
                                                                                              • Temperature probes
                                                                                                Flexible, low-mass immersion measurement tip
                                                                                                TC Type K temperature probe with flexible measuring tip, short response time and 2 m cable
                                                                                                  :
                                                                                                  0602 0493
                                                                                                • Temperature probes
                                                                                                  Wasserdichter Lebensmittelfühler aus Edelstahl (IP65)
                                                                                                  Waterproof stainless steel food probe (TC type K) - measuring range: -60 to +400°C
                                                                                                    :
                                                                                                    0602 2292
                                                                                                  • Temperature probes
                                                                                                    Thermocouple with TC adapter, flexible, 800 mm long
                                                                                                    Flexible thermoelectric couple (TC type K, glass fibre) – Measuring range: -50 to +400°C
                                                                                                      :
                                                                                                      0602 0644
                                                                                                    • Temperature probes
                                                                                                      Thermocouple with TC adapter, flexible, length 1500 mm
                                                                                                      Flexible thermoelectric couple (TC type K, glass fibre) – measuring range -50 to +400°C
                                                                                                        :
                                                                                                        0602 0645
                                                                                                      • Temperature probes
                                                                                                        Thermocouple with TC adapter, flexible, 1500 mm long, PTFE
                                                                                                        Flexible thermoelectric couple (TC type K, PTFE) – measuring range -50 to +250°C
                                                                                                          :
                                                                                                          0602 0646
                                                                                                        • Temperature probes
                                                                                                          testo 115i
                                                                                                          testo 115i - Clamp thermometer operated via smartphone
                                                                                                            :
                                                                                                            0560 2115 02
                                                                                                          • Temperature probes
                                                                                                            testo 915i
                                                                                                            testo 915i - Thermometer with air probe (TC type K) and smartphone operation
                                                                                                              :
                                                                                                              0563 3915
                                                                                                            • Velocity

                                                                                                            • Velocity
                                                                                                              Hot wire probe (digital) with Bluetooth® including temperature and humidity sensor
                                                                                                              Hot wire probe (digital) with Bluetooth® including temperature and humidity sensor: for measurements in ventilation ducts – measuring range 0 to +30 m/s, -20 to +70 °C, 5 to 95% RH
                                                                                                                :
                                                                                                                0635 1571
                                                                                                              • Velocity
                                                                                                                Hot wire probe (digital) including temperature and humidity sensor, wired
                                                                                                                Hot wire probe (digital) including temperature and humidity sensor, wired: for measurements in ventilation ducts – measuring range 0 to +30 m/s, -20 to +70 °C, 5 to 95% RH
                                                                                                                  :
                                                                                                                  0635 1572
                                                                                                                • Velocity
                                                                                                                  Hot wire probe head including temperature and humidity sensor
                                                                                                                  Hot wire probe head including temperature and humidity sensor: for attachment to extendable telescope for air velocity probes with universal handle – measuring range 0 to +30 m/s, -20 to +70 °C, 5 to 95% RH
                                                                                                                    :
                                                                                                                    0635 1570
                                                                                                                  • Velocity
                                                                                                                    Vane probe (Ø 16 mm, digital) with Bluetooth®, including temperature sensor
                                                                                                                    Vane probe (Ø 16 mm, digital) with Bluetooth® including temperature sensor: for measurements in ventilation ducts – measuring range +0.6 to +50 m/s, -10 to +70 °C
                                                                                                                      :
                                                                                                                      0635 9571
                                                                                                                    • Velocity
                                                                                                                      Vane probe (Ø 16 mm, digital) including temperature sensor, wired
                                                                                                                      Vane probe (Ø 16 mm, digital) including temperature sensor, wired: for measurements in ventilation ducts – measuring range +0.6 to +50 m/s, -10 to +70 °C
                                                                                                                        :
                                                                                                                        0635 9572
                                                                                                                      • Velocity
                                                                                                                        16 mm vane probe head including temperature sensor
                                                                                                                        16 mm vane probe head including temperature sensor; for attachment to extendable telescope for air velocity probes with universal handle – measuring range +0.6 to +50 m/s, -10 to +70 °C
                                                                                                                          :
                                                                                                                          0635 9570
                                                                                                                        • Velocity
                                                                                                                          Hot wire probe (digital) including temperature sensor, wired
                                                                                                                          Hot wire probe (digital) including temperature sensor, wired: for measurements in ventilation ducts – measuring range 0 to 30 m/s, -20 to +70 °C
                                                                                                                            :
                                                                                                                            0635 1032
                                                                                                                          • Velocity
                                                                                                                            Vane probe (Ø 16 mm, digital) wired
                                                                                                                            Vane probe (Ø 16 mm, digital), wired: for measurements in ventilation ducts – measuring range +0.6 to +50 m/s
                                                                                                                              :
                                                                                                                              0635 9532
                                                                                                                            • Velocity
                                                                                                                              Fume cupboard probe (digital), wired
                                                                                                                              Fume cupboard probe (digital), wired: for measuring inflow speed and exhaust air volume flow in fume cupboards according to DIN EN 14175-3/-4 – measuring range 0 to 5 m/s, 0 to +50 °C
                                                                                                                                :
                                                                                                                                0635 1052
                                                                                                                              • Velocity
                                                                                                                                High-precision vane probe (Ø 100 mm, digital) with Bluetooth® including temperature sensor
                                                                                                                                High-precision vane probe (Ø 100 mm, digital) with Bluetooth® including temperature sensor: for measurements at air outlets in cleanrooms and at plate outlets, ventilation grilles or swirl outlets – measuring range +0.1 to +15 m/s, -20 to +70 °C
                                                                                                                                  :
                                                                                                                                  0635 9371
                                                                                                                                • Velocity
                                                                                                                                  High-precision vane probe (Ø 100 mm, digital) including temperature sensor, wired
                                                                                                                                  High-precision vane probe (Ø 100 mm, digital) including temperature sensor, wired: for measurements at air outlets in cleanrooms, as well as at plate outlets, ventilation grilles or swirl outlets – measuring range +0.1 to +15 m/s, -20 to +70 °C
                                                                                                                                    :
                                                                                                                                    0635 9372
                                                                                                                                  • Velocity
                                                                                                                                    High-precision 100 mm vane probe head including temperature sensor
                                                                                                                                    High-precision 100 mm vane probe head including temperature sensor: for attachment to extendable telescope for air velocity probes with universal handle or to a universal Bluetooth® or cable handle – measuring range +0.1 to +15 m/s, -20 to +70 °C
                                                                                                                                      :
                                                                                                                                      0635 9370
                                                                                                                                    • Velocity
                                                                                                                                      Vane probe (Ø 100 mm, digital) with Bluetooth® including temperature sensor
                                                                                                                                      Vane probe (Ø 100 mm, digital) with Bluetooth® including temperature sensor: for measurements at ceiling/air outlets and at plate outlets, ventilation grilles or swirl outlets – measuring range +0.3 to +35 m/s, -20 to +70 °C
                                                                                                                                        :
                                                                                                                                        0635 9431
                                                                                                                                      • Velocity
                                                                                                                                        Vane probe (Ø 100 mm, digital) including temperature sensor, wired
                                                                                                                                        Vane probe (Ø 100 mm, digital) including temperature sensor, wired: for measurements at ceiling/air outlets and at plate outlets, ventilation grilles or swirl outlets – measuring range +0.3 to +35 m/s, -20 to +70 °C
                                                                                                                                          :
                                                                                                                                          0635 9432
                                                                                                                                        • Velocity
                                                                                                                                          100 mm vane probe head
                                                                                                                                          100 mm vane probe head: for attachment to extendable telescope for air velocity probes with universal handle or to universal Bluetooth® or cable handle – measuring range +0.3 to +35 m/s, -20 to +70 °C
                                                                                                                                            :
                                                                                                                                            0635 9430
                                                                                                                                          • Velocity
                                                                                                                                            testo 405i German Design Award
                                                                                                                                            For measuring volume flow, air velocity and temperature
                                                                                                                                              :
                                                                                                                                              0560 1405
                                                                                                                                            • Velocity
                                                                                                                                              Smart Probes VAC Set
                                                                                                                                              Measurement of air velocity, volume flow and temperature
                                                                                                                                                :
                                                                                                                                                0560 1410
                                                                                                                                              • Velocity
                                                                                                                                                Hot ball probe (Ø 3 mm) - for flow and temperature
                                                                                                                                                Hot ball probe (Ø 3 mm, digital), incl. temperature sensor, fixed cable: for measurement in non-directional air flows – measuring range 0 to 10 m/s, -20 to +70 °C
                                                                                                                                                  :
                                                                                                                                                  0635 1051
                                                                                                                                                • Velocity
                                                                                                                                                  Hot wire probe
                                                                                                                                                  Hot wire probe (Ø 7.5 mm, digital), incl. temperature sensor, fixed cable: for measurement in ventilation ducts, at plate outlets, ventilation grilles – measuring range 0 to 20 m/s, -20 to +70 °C
                                                                                                                                                    :
                                                                                                                                                    0635 1026
                                                                                                                                                  • Velocity
                                                                                                                                                    testo 420
                                                                                                                                                    Make sure you get the testo 420 volume flow hood for larger ceiling outlets and at the same time enjoy multiple maintenance benefits on HVAC systems. Because the flow hood with the removable measuring instrument is not only exceptionally light, it also guarantees accurate volume flow calculations at swirl outlets
                                                                                                                                                      :
                                                                                                                                                      0563 4200
                                                                                                                                                    • IAQ measurements in the field of air conditioning and ventilation

                                                                                                                                                      • High-precision, location-independent and built-in differential pressure sensor, smart and intuitive measurement programs for IAQ measurements in accordance with the standards, creation of documentation on site, reports, versatile combination options with IAQ probes

                                                                                                                                                      IAQ measurements in the field of air conditioning and ventilation

                                                                                                                                                      Custom-combine your Testo IAQ measuring instrument with IAQ probes and accessories for your application.
                                                                                                                                                       
                                                                                                                                                      With the right products, you can handle all kinds of IAQ applications:
                                                                                                                                                       
                                                                                                                                                      • Air flow measurements: Flow measurements in ducts, at outlets and on filters as per EN ISO 12599 and ASHRAE 111
                                                                                                                                                      • Comfort level measurements: Measurement of indoor air quality or turbulence as per EN ISO 7730 and ASHRAE 55, NET measurement as per DIN 33403, PMV/PPD as per EN ISO 7730 and ASHRAE 55, WBGT measurement as per DIN 33403 and EN ISO 7243
                                                                                                                                                      • Measurements in laboratories and cleanrooms: Flow measurements in fume cupboards as per DIN EN 14175-3/-4, differential pressure measurements and laminar flow measurements in cleanrooms, humidity measurements in cleanrooms

                                                                                                                                                      Contact Us
                                                                                                                                                      Testo Ltd
                                                                                                                                                      Newman Lane
                                                                                                                                                      GU34 2URAlton
                                                                                                                                                      HampshireUnited Kingdom
                                                                                                                                                      01420 544433

                                                                                                                                                      Opening hours

                                                                                                                                                      Monday-Thursday: 8:30am - 17:00pmFriday: 8:30am - 16:00pm

                                                                                                                                                      © 2026

                                                                                                                                                      Image