738 reviews
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About this app

- All in one: The testo Smart App guides you easily and quickly through measurements on refrigeration, air conditioning and heating systems, air flow, and many more applications.
- Fast: Graphically descriptive display of measured values, e.g. as a table, for quick interpretation of results.
- Efficient: Create digital measurement reports including. photos as PDF/ CSV files on site and send them via e-mail.

The testo Smart App is compatible with the following Bluetooth®-enabled measuring instruments from Testo:
- All Testo Smart Probes
- Digital manifolds testo 550s/557s/550i and testo 550/557
- Digital refrigerant scale testo 560i
- Flue gas analyzer testo 300
- Vacuum gauge testo 552
- Clamp meter testo 770-3
- Volume flow hood testo 420
- Compact HVAC measuring instruments

Applications with the testo Smart App
Refrigeration systems, air conditioning systems and heat pumps, heating systems, indoor air quality:
- Leak test: Recording and analysis of the pressure drop curve.
- Superheat and subcooling: Automatic determination of condensation and evaporation temperature and calculation of superheat / subcooling.
- Target superheat: Automatic calculation of target superheat
- Automatic refrigerant charging by weight, by superheat, by subcooling, and by target superheat
- Vacuum measurement: Graphical progress display of the measurement with indication of start and differential value

Indoor air quality and comfort level:
- Temperature and humidity: Automatic calculation of dew point and wet bulb temperature

Ventilation systems:
- Volume flow: After the intuitive input of the duct cross-section, the app calculates the volume flow fully automatically.
- Diffuser measurements: simple parameterisation of the diffuser (dimensions and geometry), comparison of the volume flows of several diffusers when setting up a ventilation system, continuous and multi-point average calculation.

Heating systems:
- Flue gas measurement: Second screen function in combination with testo 300
- Measurement of gas flow and static gas pressure: Also possible parallel to the flue gas measurement (delta P)
- Measurement of flow and return temperatures (delta T)
Updated on
Apr 26, 2023

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
This app may share these data types with third parties
App info and performance and Device or other IDs
No data collected
Learn more about how developers declare collection
Data is encrypted in transit
Data can’t be deleted

Ratings and reviews

700 reviews
Tyler Heffernan
June 28, 2021
It is hard to rate, because the functions and amount of things you can do are amazing, and for that i give 10 stars.. however the user interface is not very user friendly, and very difficult to maneuver. If Testo makes the app easier to navigate, and find the different settings and options, this would be the best app for any bluetooth tool ever made.
13 people found this review helpful
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Michael Wolins
August 15, 2022
Bought new 550s because the 2 year old 550 would constantly freeze without notice. Now the new update crashes on S22 Ultra. Failure notice says: "testo Smart crashed because this app has a bug". They are great when they work, and the data is useful for troubleshooting. But for this much money this low level of reliability is hard to justify.
16 people found this review helpful
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Testo SE & Co. KGaA
August 19, 2022
Please try to deactivate VPN if you use it on your smartphone, then the app can be started successfully. If you don´t use VPN, please contact us directly at info@testo.de . We are currently working at full speed to find a suitable solution. Your testo team!
Mike Whocares
May 30, 2023
Tools work. Testo isn't the most rugged device. In the latest version the graphing function is completely broken in second screen mode. I hate second screen mode, I wish it would just import the data like every other sensor. I demand that you allow us to make our own "measurement modes" in the app. Often I'll be using a combination that won't show all sensors while using a specific mode. And why would you disable the older app completely with an update. You just couldn't leave it alone.
1 person found this review helpful
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What's new

Printing of measurement results on the testo BT printer (order no. 0554 0621)
Alarming: Storage of limit values for each measurement parameter.
New database: Transfer of stored measured values to the new & more powerful database.
Export & import of measured values: In the case of a smartphone or tablet change, simply export the measured values and import them again.